Sotos Syndrome

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Summary

Clinical characteristics.

Sotos syndrome is characterized by a distinctive facial appearance (broad and prominent forehead with a dolichocephalic head shape, sparse frontotemporal hair, downslanting palpebral fissures, malar flushing, long and narrow face, long chin); learning disability (early developmental delay, mild-to-severe intellectual impairment); and overgrowth (height and/or head circumference ≥2 SD above the mean). These three clinical features are considered the cardinal features of Sotos syndrome. Major features of Sotos syndrome include behavioral problems (most notably autistic spectrum disorder), advanced bone age, cardiac anomalies, cranial MRI/CT abnormalities, joint hyperlaxity with or without pes planus, maternal preeclampsia, neonatal complications, renal anomalies, scoliosis, and seizures.

Diagnosis/testing.

The diagnosis of Sotos syndrome is established in a proband by identification of a heterozygous NSD1 pathogenic variant or a deletion encompassing NSD1 on molecular genetic testing.

Management.

Treatment of manifestations: Referral to appropriate specialists for management of learning disability / speech delays, behavior problems, cardiac abnormalities, renal anomalies, scoliosis, seizures; intervention is not recommended if the brain MRI shows ventricular dilatation without raised intracranial pressure.

Surveillance: Regular review by a general pediatrician for younger children, individuals with many medical complications, and families requiring more support than average; less frequent review of older children / teenagers and those individuals without many medical complications.

Genetic counseling.

Sotos syndrome is inherited in an autosomal dominant manner. More than 95% of individuals have a de novo pathogenic variant. If neither parent of a proband has Sotos syndrome, the risk to sibs of the proband is low (<1%). The risk to offspring of affected individuals is 50%. Prenatal testing for pregnancies at risk and preimplantation genetic diagnosis are possible if the NSD1 pathogenic variant has been identified in an affected family member.

Diagnosis

Suggestive Findings

No formal clinical diagnostic criteria are published for Sotos syndrome; the clinical diagnosis should be suspected in individuals with the following features.

Characteristic facial appearance (most easily recognizable between ages 1 and 6 years):

  • Broad, prominent forehead with a dolichocephalic head shape
  • Sparse frontotemporal hair
  • Downslanting palpebral fissures
  • Malar flushing
  • Long narrow face (particularly bitemporal narrowing)
  • Long chin
    Note: Facial shape is retained into adulthood; with time the chin becomes broader (squarer in shape).

Learning disability

  • Early developmental delay
  • Mild-to-severe intellectual impairment

Overgrowth

  • Height and/or head circumference ≥2 SD above the mean (i.e., ~98th centile)
    Note: Height may normalize in adulthood.
  • Macrocephaly usually present at all ages

Note: Based on the analysis of more than 266 individuals with an NSD1 pathogenic variant, the three cardinal features (facial appearance, learning disability, and overgrowth) were shown to occur in at least 90% of affected individuals [Tatton-Brown et al 2005b].

Establishing the Diagnosis

The diagnosis of Sotos syndrome is established in a proband by identification of a heterozygous pathogenic variant in NSD1 or a deletion encompassing NSD1 on molecular genetic testing (see Table 1).

Molecular genetic testing approaches can include a combination of gene-targeted testing (single-gene testing and multigene panel) and comprehensive genomic testing (chromosomal microarray analysis, exome sequencing, exome array, genome sequencing) depending on the phenotype.

Gene-targeted testing requires that the clinician determine which gene(s) are likely involved, whereas genomic testing does not. Because the phenotype of Sotos syndrome is broad, individuals with the distinctive findings described in Suggestive Findings are likely to be diagnosed using gene-targeted testing (see Option 1), whereas those with atypical features in whom the diagnosis of Sotos syndrome has not been considered are more likely to be diagnosed using genomic testing (see Option 2).

Option 1

When the phenotypic and laboratory findings suggest the diagnosis of Sotos syndrome, molecular genetic testing approaches can include single-gene testing or use of a multigene panel:

  • Single-gene testing. Sequence analysis of NSD1 detects small intragenic deletions/insertions and missense, nonsense, and splice site variants; typically, exon or whole-gene deletions/duplications are not detected. Perform sequence analysis first. If no pathogenic variant is found, perform gene-targeted deletion/duplication analysis to detect intragenic deletions or duplications.
    Note: Chromosomal microarray analysis (CMA) uses oligonucleotide or SNP arrays to detect genome-wide large deletions/duplications (including NSD1) that cannot be detected by sequence analysis. Many individuals with developmental delay will have had CMA as part of their evaluation, sometimes prior to the consideration of Sotos syndrome as a possibility. CMA designs in current clinical use target the NSD1 region. Gene-targeted deletion/duplication assays may have higher resolution than CMA; however, testing is unlikely to detect a deletion or duplication in cases where sequence analysis and CMA of NSD1 was not diagnostic.
  • A multigene panel that includes NSD1 and other genes of interest (see Differential Diagnosis) is most likely to identify the genetic cause of the condition at the most reasonable cost while limiting identification of variants of uncertain significance and pathogenic variants in genes that do not explain the underlying phenotype. Note: (1) The genes included in the panel and the diagnostic sensitivity of the testing used for each gene vary by laboratory and are likely to change over time. (2) Some multigene panels may include genes not associated with the condition discussed in this GeneReview. (3) In some laboratories, panel options may include a custom laboratory-designed panel and/or custom phenotype-focused exome analysis that includes genes specified by the clinician. (4) Methods used in a panel may include sequence analysis, deletion/duplication analysis, and/or other non-sequencing-based tests.
    For this disorder a multigene panel that also includes deletion/duplication analysis is recommended (see Table 1).
    For an introduction to comprehensive genomic testing click here. More detailed information for clinicians ordering genomic testing can be found here.

Option 2

When the diagnosis of Sotos syndrome is not considered because an individual has atypical phenotypic features, comprehensive genomic testing (which does not require the clinician to determine which gene[s] are likely involved) is the best option. Exome sequencing is the most commonly used genomic testing method; genome sequencing is also possible.

Exome array (when clinically available) may be considered if exome sequencing is not diagnostic.

For an introduction to comprehensive genomic testing click here. More detailed information for clinicians ordering genomic testing can be found here.

Table 1.

Molecular Genetic Testing Used in Sotos Syndrome

Gene 1MethodProportion of Probands with a Pathogenic Variant 2 Detectable by Method
NSD1Sequence analysis 345%-80%
CMA 415%-50% 5, 6
Gene-targeted deletion/duplication analysis 720%-55% 7, 8
1.

See Table A. Genes and Databases for chromosome locus and protein.

2.

See Molecular Genetics for information on allelic variants detected in this gene.

3.

Sequence analysis detects variants that are benign, likely benign, of uncertain significance, likely pathogenic, or pathogenic. Pathogenic variants may include small intragenic deletions/insertions and missense, nonsense, and splice site variants; typically, exon or whole-gene deletions/duplications are not detected. For issues to consider in interpretation of sequence analysis results, click here.

4.

Chromosomal microarray analysis (CMA) uses oligonucleotide or SNP arrays to detect genome-wide large deletions/duplications (including NSD1) that cannot be detected by sequence analysis. The ability to determine the size of the deletion/duplication depends on the type of microarray used and the density of probes in the 5q35 region. Typically, single-exon deletions or duplications are below the resolution of CMA detection. CMA designs in current clinical use target the 5q35 region and NSD1.

5.

ClinGen-ISCA-37425. Standardized clinical annotation and interpretation for genomic variants from the Clinical Genome Resource (ClinGen) project (formerly the International Standards for Cytogenomic Arrays [ISCA] Consortium).

6.

The incidence of the common 1.9-Mb deletion varies by population [Kurotaki et al 2003, Tatton-Brown et al 2005a, Tatton-Brown et al 2005b, Visser et al 2005].

7.

Gene-targeted deletion/duplication analysis detects intragenic deletions or duplications. Methods used may include quantitative PCR, long-range PCR, multiplex ligation-dependent probe amplification (MLPA), and a gene-targeted microarray designed to detect single-exon deletions or duplications. Gene-targeted deletion/duplication testing will detect deletions ranging from a single exon to the whole gene; however, breakpoints of large deletions and/or deletion of adjacent genes (e.g., the 1.9-Mb deletion) may not be detected by these methods.

8.

Gene-targeted deletion/duplication analysis may detect an additional 1%-5% of partial-gene deletions.

Clinical Characteristics

Clinical Description

Based on a review of 266 persons with NSD1 abnormalities, the clinical features of Sotos syndrome were classified as cardinal features (occurring in ≥90% of affected individuals), major features (occurring in 15%-89%), and associated features (occurring in ≥2% and <15% of persons) [Tatton-Brown et al 2005b].

Cardinal features (present in ≥90% of persons with Sotos syndrome)

  • Characteristic facial appearance
  • Learning disability
  • Overgrowth (height and/or head circumference ≥2 SD above mean)

Major features (present in 15%-89% of persons with Sotos syndrome)

  • Behavioral problems – most notably autistic spectrum disorder
  • Advanced bone age
  • Cardiac anomalies
  • Cranial MRI/CT abnormalities
  • Joint hyperlaxity with or without pes planus
  • Maternal preeclampsia
  • Neonatal complications
  • Renal anomalies
  • Scoliosis
  • Seizures

Cardinal Features

Characteristic facial appearance. The facial gestalt is the most specific diagnostic criterion for Sotos syndrome, and also the one most open to observer error due to inexperience. The facial gestalt of Sotos syndrome is evident at birth, but becomes most recognizable between ages one and six years. The head is dolichocephalic and the forehead broad and prominent. Often the hair in the frontotemporal region is sparse. The palpebral fissures are usually downslanting. Malar flushing may be present. In childhood the jaw is narrow with a long chin; in adulthood the chin broadens [Allanson & Cole 1996, Tatton-Brown & Rahman 2004]. In older children and adults, the facial features, although still typical, can be more subtle [Allanson & Cole 1996, Tatton-Brown et al 2005b].

Learning disability. Delay of early developmental milestones is very common and motor skills may appear particularly delayed because of a child's large size, hypotonia, and poor coordination. The majority of individuals with Sotos syndrome have some degree of intellectual impairment. The spectrum is broad and ranges from a mild learning disability (affected individuals would be expected to live independently and have their own families) to a severe learning disability (affected individuals would be unlikely to live independently as adults). The level of intellectual impairment generally remains stable throughout life [Tatton-Brown et al 2005b, Foster et al 2019]. The learning disability in children with Sotos syndrome is characterized by relative strength in verbal ability and visuospatial memory but relative weakness in nonverbal reasoning ability and quantitative reasoning [Lane et al 2019].

Overgrowth. Sotos syndrome is associated with overgrowth of prenatal onset. Delivery is typically at term. The average birth length approximates to the 98th centile and the average birth head circumference is between the 91st and 98th centiles. Average birth weight is within the normal range (50th-91st centile).

Before age ten years, affected children often demonstrate rapid linear growth. They are often described as being considerably taller than their peers. Approximately 90% of children have a height and/or head circumference at least 2 SD above the mean [Tatton-Brown et al 2005b]. However, growth is also influenced by parental heights and some individuals do not have growth parameters above the 98th centile [Cole & Hughes 1994, Tatton-Brown et al 2005b].

Height may normalize in adulthood, but macrocephaly is usually present at all ages [Agwu et al 1999, Foster et al 2019]. Data on final adult height are scarce; however, in both men and women, the range of final adult height is broad [Agwu et al 1999, Foster et al 2019].

The de Boer et al [2005] study of auxologic data supports that of Agwu et al [1999] and shows that individuals with an NSD1 pathogenic variant have an increased arm span / height ratio, decreased sitting/standing height ratio, and increased hand length. These data suggest that the increased height in Sotos syndrome is predominantly the result of an increase in limb length [Agwu et al 1999, de Boer et al 2005].

Major Features

Behavioral problems. A wide range of behavioral problems are common at all ages: autistic spectrum disorder, phobias, and aggression have been described [Sheth et al 2015; Lane et al 2017; Lane et al 2019; Foster et al 2019; Tatton-Brown, personal communication]. Often difficulty with peer group relationships is precipitated by large size, naiveté, and lack of awareness of social cues [Finegan et al 1994]. These observations were confirmed in a study of individuals with a clinical diagnosis of Sotos syndrome (some with and some without an NSD1 pathogenic variant); it was additionally noted that attention-deficit/hyperactivity disorder is not common among individuals with Sotos syndrome [de Boer et al 2006].

Advanced bone age. Bone age often reflects the accelerated growth velocity and is advanced in 75%-80% of prepubertal children. However, bone age interpretation is influenced by the "threshold" taken as significant, the method of assessment, subjective interpretative error, and the age at which the assessment is made.

Cardiac anomalies. About 20% of individuals have cardiac anomalies that range in severity from single, often self-limiting anomalies (including patent ductus arteriosus, atrial septal defect, and ventricular septal defect) to more severe, complex cardiac abnormalities. Two unrelated individuals with Sotos syndrome have been shown to have left ventricular non-compaction [Martinez et al 2011]. Three adult patients with Sotos syndrome and aortic dilatation have been reported [Hood et al 2016].

Cranial MRI/CT abnormalities are identified in the majority of individuals with Sotos syndrome and an NSD1 pathogenic variant. Ventricular dilatation (particularly in the trigone region) is most frequently identified; other abnormalities include midline changes (hypoplasia or agenesis of the corpus callosum, mega cisterna magna, cavum septum pellucidum), cerebral atrophy, and small cerebellar vermis [Waggoner et al 2005].

Joint hyperlaxity / pes planus. Joint laxity is reported in at least 20% of individuals with Sotos syndrome.

Maternal preeclampsia occurs in about 15% of pregnancies of children with Sotos syndrome.

Neonatal complications. Neonates may have jaundice (~65%), hypotonia (~75%), and poor feeding (~70%). These complications tend to resolve spontaneously, but in a small minority intervention is required.

Renal anomalies. About 15% of individuals with an NSD1 pathogenic variant have a renal anomaly; vesicoureteral reflux is the most common. Some individuals may have quiescent vesicoureteral reflux and may present in adulthood with renal impairment.

Scoliosis. Present in about 30% of affected individuals, scoliosis is rarely severe enough to require bracing or surgery.

Seizures. Approximately 25% of individuals with Sotos syndrome develop non-febrile seizures at some point in their lives and some require ongoing therapy. Absence, tonic-clonic, myoclonic, and partial complex seizures have all been reported.

Associated Features

Tumors occur in approximately 3% of persons with Sotos syndrome. The broad range includes sacrococcygeal teratoma, neuroblastoma, presacral ganglioma, acute lymphoblastic leukemia, small-cell lung cancer, and astrocytoma [Hersh et al 1992, Tatton-Brown & Rahman 2004, Theodoulou et al 2015]. De Boer and colleagues have characterized and reviewed these problems and compared persons with Sotos syndrome who have NSD1 pathogenic variants to those who do not [de Boer et al 2006].

Various other clinical features have been associated with Sotos syndrome. Some associated features, such as constipation and hearing problems caused by chronic otitis media, are common. The following features are seen in ≥2% and <15% of individuals with Sotos syndrome [Tatton-Brown et al 2005b]:

  • Astigmatism
  • Cataract
  • Cholesteatoma
  • Conductive hearing loss
  • Constipation
  • Contractures
  • Craniosynostosis
  • Cryptorchidism
  • Gastroesophageal reflux
  • Hemangioma
  • Hemihypertrophy
  • Hirschsprung's disease
  • Hydrocele
  • Hypercalcemia
  • Hypermetropia
  • Hypodontia
  • Hypoplastic nails
  • Hypospadias
  • Hypothyroidism
  • Inguinal hernia
  • Myopi
  • Neonatal hypoglycemia
  • Nystagmus
  • Pectus excavatu
  • Phimosis
  • Skin hyperpigmentation
  • Skin hypopigmentation
  • Strabismus
  • Subpleural blebs
  • Talipes equinovarus
  • Umbilical hernia
  • Vertebral anomalies
  • 2/3 toe syndactyly

Genotype-Phenotype Correlations

Through the evaluation of 234 individuals with Sotos syndrome with an NSD1 abnormality, it has been shown that, in general, individuals with a 5q35 microdeletion have less overgrowth and more severe learning disability than individuals with an intragenic pathogenic variant [Tatton-Brown et al 2005b].

Genotype-phenotype correlations between intragenic pathogenic variants and 5q35 microdeletions are not evident for other clinical features associated with Sotos syndrome (i.e., cardiac abnormalities, renal anomalies, seizures, scoliosis) – nor were correlations observed between type of intragenic pathogenic variant (missense vs truncating) and phenotype or between position of pathogenic variant (5' vs 3') and phenotype [Tatton-Brown et al 2005b].

Penetrance

NSD1 molecular testing is now routinely undertaken in diagnostic genetic laboratories. To date, no unaffected parent or sib with an NSD1 pathogenic variant has been reported [Douglas et al 2003, Rio et al 2003, Türkmen et al 2003, Tatton-Brown et al 2005b]. Thus, Sotos syndrome appears to be a fully penetrant condition.

Of note, expressivity is highly variable. Individuals with the same pathogenic variant, even within the same family, can be affected differently [Tatton-Brown et al 2005b, Donnelly et al 2011].

Nomenclature

Sotos syndrome has previously been referred to as cerebral gigantism. This term is now outdated and should no longer be used.

Prevalence

Sotos syndrome is estimated to occur in 1:14,000 live births [Authors, unpublished data].

Differential Diagnosis

Overgrowth conditions that may be confused with Sotos syndrome are summarized in Table 2.

Table 2.

Overgrowth Conditions to Consider in the Differential Diagnosis of Sotos Syndrome

Differential
Diagnosis
Disorder
Gene(s)MOIClinical Features of Differential Diagnosis Disorder
Overlapping w/Sotos SyndromeDistinguishing from Sotos Syndrome
EZH2-related Weaver syndrome (Weaver-Smith syndrome) 1EZH2 2AD
  • Typical but subtle facial appearance, esp in early childhood 3
  • ↑ height; macrocephaly; scoliosis; ligamentous laxity
  • Frequently hypotonic at birth (may present w/mixed central hypotonia / peripheral hypertonia)
  • Round face shape w/ocular hypertelorism
  • Prognathism is not a feature of Weaver syndrome, but chin appears "stuck on," frequently w/a horizontal crease between chin & lower lip.
  • Associated joint problems (e.g., camptodactyly & contractures)
  • Infants often have hoarse, low-pitched cry.
Cohen-Gibson syndrome 1, 4
(OMIM 617561)
EEDAD
  • Typical but subtle facial appearance, esp in early childhood
  • ↑ height; macrocephaly; scoliosis; ligamentous laxity
  • Frequently hypotonic at birth (may present w/mixed central hypotonia / peripheral hypertonia)
  • The face is subtly different, w/hypertelorism, round face, & "stuck-on" chin.
  • Other features that do not overlap w/Sotos syndrome are most similar to Weaver syndrome.
SUZ12-overgrowth syndrome 1, 5SUZ12AD
  • Typical but subtle facial appearance, esp in early childhood
  • ↑ height; macrocephaly; scoliosis; ligamentous laxity
  • Frequently hypotonic at birth (may present w/mixed central hypotonia / peripheral hypertonia)
Features that do not overlap w/Sotos syndrome are most similar to Weaver syndrome.
Beckwith-Wiedemann syndrome (BWS)See footnote 6ADFrequently weight &/or height are ≥2 SD at birth.
  • BWS should be clinically distinguishable from Sotos syndrome (molecular testing is indicated in individuals w/clinical overlap). 7
  • Macroglossia
  • Anterior earlobe creases / helical pits
  • Omphalocele
  • Visceromegaly
  • ↑ risk of embryonal tumors, esp Wilms tumor
Simpson-Golabi-Behmel syndrome type 1GPC3
GPC4
XL
  • Pre- & postnatal overgrowth
  • Variable ID
  • Predominantly affects males
  • Polydactyly
  • Supernumerary nipples
  • Diastasis recti
  • Pectus excavatum
  • Facial gestalt differs. 8
Bannayan-Riley-Ruvalcaba syndrome
(see PTEN Hamartoma Tumor Syndrome)
PTENAD
  • Macrocephaly
  • Somewhat similar facial gestalt
  • May be associated w/autistic spectrum disorder
  • Vascular malformations
  • Hamartomatous polyps of distal ileum & colon
  • Pigmented macules on shaft of penis
  • Lipomas
  • ↑ risk of thyroid & breast cancer 8
Fragile X syndrome
(see FMR1-Related Disorders)
FMR1XL
  • Macrocephaly
  • ID
  • Typical but subtle facial appearance may overlap w/Sotos syndrome: dolicocephalic head shape, prominent jaw & forehead.
  • Predominantly affects males
  • Affected males often have large ears; not common in Sotos syndrome.
  • Macro-orchidism after puberty 9
Nevoid basal cell carcinoma syndrome (Gorlin syndrome)PTCH
SUFU
AD
  • Recognizable appearance w/macrocephaly, bossing of forehead, & coarse facial features (in ~60% of affected individuals)
  • Head circumference ↑ to >98th centile until age 10-18 mos
  • Development of multiple jaw keratocysts, frequently beginning in 2nd decade
  • Basal cell carcinomas usually from 3rd decade onward
  • Skeletal anomalies (e.g., bifid ribs or wedge-shaped vertebrae)
  • Absence, usually, of DD 9
Malan syndrome 10
(OMIM 614753)
NFIXAD
  • Characteristic facial appearance w/dolicocephaly, prominent forehead, & downslanting palpebral fissures
  • Scoliosis; ↑ height (>2 SD) in childhood
  • Associated w/variable ID
  • Ophthalmic abnormalities are common in Malan syndrome; less common in Sotos syndrome.
  • ↑ height is less common in older children & adults. 9

AD = autosomal dominant; AR = autosomal recessive; DD = developmental delay; ID = intellectual disability; MOI = mode of inheritance; XL = X-linked

1.

Given the overlap in findings between Sotos syndrome, Weaver syndrome, Cohen-Gibson syndrome, and SUZ12-related overgrowth, in probands with features suggestive of Weaver syndrome, the recommended testing order is NSD1, followed by EZH2, followed by EED, followed by SUZ12.

2.

Weaver syndrome, caused by pathogenic variants in another histone methyl transferase gene, EZH2, is a clinical entity distinct from Sotos syndrome [Tatton-Brown et al 2011, Gibson et al 2012].

3.

In some individuals thought to have Weaver syndrome but in whom NSD1 pathogenic variants were identified, the clinical phenotype evolved to be consistent with Sotos syndrome [Douglas et al 2003, Rio et al 2003, Tatton-Brown et al 2005b].

4.

Cohen et al [2015]

5.

Imagawa et al [2017]

6.

Molecular genetic testing can identify epigenetic and genomic alterations of chromosome 11p15 in individuals with BWS: (1) loss of methylation on the maternal chromosome at imprinting center 2 (IC2) in 50% of affected individuals; (2) paternal uniparental disomy for chromosome 11p15 in 20%; and (3) gain of methylation on the maternal chromosome at imprinting center 1 (IC1) in 5%. Sequence analysis of CDKN1C identifies pathogenic variants in approximately 40% of familial cases and 5%-10% of cases with no family history of BWS. Approximately 85% of individuals with BWS have no family history of BWS while approximately 15% have a family history consistent with autosomal dominant transmission of BWS.

7.

NSD1 pathogenic variants were reported in two individuals with BWS; however, the individuals do not fulfill diagnostic criteria for BWS and do fulfill diagnostic criteria for Sotos syndrome [Baujat et al 2004, Tatton-Brown & Rahman 2004].

8.

Detailed clinical examination & molecular genetic testing should differentiate the disorder from Sotos syndrome.

9.

Usually distinguishable from Sotos syndrome on clinical grounds; molecular testing confirms the diagnosis.

10.

Priolo et al [2018]

Other conditions to consider in the differential diagnosis of Sotos syndrome include the following:

  • Chromosome abnormalities. A Sotos syndrome-like phenotype has been associated with 4p duplications, mosaic 20p trisomy [Faivre et al 2000], and 22q13.3 deletion syndrome.
  • Nonspecific overgrowth. Many individuals with overgrowth do not fulfill the diagnostic criteria for any of the above conditions but nevertheless have other features (e.g., learning difficulties, distinctive facial features) that suggest an underlying genetic cause. Nonspecific overgrowth is likely to be a heterogeneous group of conditions with multiple causes.

Management

Evaluations Following Initial Diagnosis

To establish the extent of disease and needs in an individual diagnosed with Sotos syndrome, the following evaluations (if not performed as part of the evaluation that led to the diagnosis) are recommended [Tatton-Brown & Rahman 2007]:

  • A thorough history to identify known features of Sotos syndrome: learning difficulties, cardiac and renal anomalies, seizures, and scoliosis
  • Physical examination including cardiac auscultation, blood pressure measurement, and back examination for scoliosis
  • Investigations to detect abnormalities before they result in significant morbidity or mortality:
    • In children in whom the diagnosis has just been established, echocardiogram and renal ultrasound examination
    • In adults in whom the diagnosis has just been established, renal ultrasound examination to evaluate for renal damage from quiescent chronic vesicoureteral reflux
    • Referral for audiologic assessment. Conductive hearing loss may occur at an increased frequency in Sotos syndrome; thus, the threshold for referral should be low.
  • Consultation with a clinical geneticist and/or genetic counselor

Treatment of Manifestations

When clinical problems (e.g., cardiac anomalies, renal anomalies, scoliosis, or seizures) are identified, referral to the appropriate specialist is recommended.

If brain MRI has been performed and ventricular dilatation demonstrated, shunting should not usually be necessary as the "arrested hydrocephalus" associated with Sotos syndrome is typically not obstructive and not associated with raised intracranial pressure. If raised intracranial pressure is suspected, investigation and management in consultation with neurologists and neurosurgeons would be appropriate.

Developmental Delay / Intellectual Disability Management Issues

For difficulties with learning/behavior/speech that can be found in individuals with Sotos syndrome, the following information represents typical management recommendations for individuals with developmental delay / intellectual disability in the United States; standard recommendations may vary from country to country.

Ages 0-3 years. Referral to an early intervention program is recommended for access to occupational, physical, speech, and feeding therapy. In the US, early intervention is a federally funded program available in all states.

Ages 3-5 years. In the US, developmental preschool through the local public school district is recommended. Before placement, an evaluation is made to determine needed services and therapies and an individualized education plan (IEP) is developed.

Ages 5-21 years

  • In the US, an IEP based on the individual's level of function should be developed by the local public school district. Affected children are permitted to remain in the public school district until age 21.
  • Discussion about transition plans including financial, vocation/employment, and medical arrangements should begin at age 12 years. Developmental pediatricians can provide assistance with transition to adulthood.

All ages. Consultation with a developmental pediatrician is recommended to ensure the involvement of appropriate community, state, and educational agencies and to support parents in maximizing quality of life.

Consideration of private supportive therapies based on the affected individual's needs is recommended. Specific recommendations regarding type of therapy can be made by a developmental pediatrician.

In the US:

  • Developmental Disabilities Administration (DDA) enrollment is recommended. DDA is a public agency that provides services and support to qualified individuals. Eligibility differs by state but is typically determined by diagnosis and/or associated cognitive/adaptive disabilities.
  • Families with limited income and resources may also qualify for supplemental security income (SSI) for their child with a disability.

Motor Dysfunction

Gross motor dysfunction

  • Physical therapy is recommended to maximize mobility and to reduce the risk for later-onset orthopedic complications (e.g., contractures, scoliosis, hip dislocation).
  • Consider use of durable medical equipment as needed (e.g., wheelchairs, walkers, bath chairs, orthotics, adaptive strollers).
  • For muscle tone abnormalities including hypertonia or dystonia, consider involving appropriate specialists to aid in management of baclofen, Botox®, anti-parkinsonian medications, or orthopedic procedures.

Fine motor dysfunction. Occupational therapy is recommended for difficulty with fine motor skills that affect adaptive function such as feeding, grooming, dressing, and writing.

Oral motor dysfunction. Assuming that the individual is safe to eat by mouth, feeding therapy – typically from an occupational or speech therapist – is recommended for affected individuals who have difficulty feeding due to poor oral motor control.

Communication issues. Consider evaluation for alternative means of communication (e.g., Augmentative and Alternative Communication [AAC]) for individuals who have expressive language difficulties.

Social/Behavioral Concerns

Children may qualify for and benefit from interventions used in treatment of autism spectrum disorder, including applied behavior analysis (ABA). ABA therapy is targeted to the individual child's behavioral, social, and adaptive strengths and weaknesses and is typically performed one on one with a board-certified behavior analyst.

Consultation with a developmental pediatrician may be helpful in guiding parents through appropriate behavioral management strategies or providing prescription medications when necessary.

Concerns about serious aggressive or destructive behavior can be addressed by a pediatric psychiatrist.

Prevention of Secondary Complications

Antibiotic prophylaxis is indicated in individuals with vesicoureteral reflux.

Surveillance

Regular evaluation by a general pediatrician is recommended for younger children, individuals with many medical complications needing coordination of medical specialists, and families requiring more support than average [Tatton-Brown & Rahman 2007].

The clinician may wish to evaluate older children, teenagers, and those individuals without many medical complications less frequently.

Table 3.

Recommended Surveillance for Individuals with Sotos Syndrome

System/ConcernEvaluationFrequency
CardiacEvaluation by cardiologistAt clinical review
Echocardiogram
  • Baseline echocardiogram at diagnosis
  • Need for & timing of follow-up studies determined by cardiologist
Blood pressure checkAt clinical review
SkeletalExamine spine for curvature.At clinical review
Urinary tractUrinalysis, urine culture for quiescent urine infectionAt clinical review
EyesOphthalmologic examWhere there are concerns
EarsHearing testWhere there are concerns

Note: Cancer screening is not recommended [Villani et al 2017]:

  • The absolute risk of sacrococcygeal teratoma and neuroblastoma is low (~1%) [Tatton-Brown et al 2005b, Tatton-Brown & Rahman 2007, Foster et al 2019]. This level of risk does not warrant routine screening, particularly as screening for neuroblastoma has not been shown to decrease mortality and can lead to false positive results [Schilling et al 2002].
  • Wilms tumor risk is not significantly increased and routine renal ultrasound examination is not indicated [Scott et al 2006].

Evaluation of Relatives at Risk

See Genetic Counseling for issues related to testing of at-risk relatives for genetic counseling purposes.

Therapies Under Investigation

Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.