Osteopathia Striata With Cranial Sclerosis

A number sign (#) is used with this entry because of evidence that osteopathia striata with cranial sclerosis (OSCS) is caused by mutation in the WTX gene (AMER1; 300647) on chromosome Xq11.

Description

Osteopathia striata with cranial sclerosis is an X-linked dominant sclerosing bone dysplasia that presents in females with macrocephaly, cleft palate, mild learning disabilities, sclerosis of the long bones and skull, and longitudinal striations visible on radiographs of the long bones, pelvis, and scapulae (Jenkins et al., 2009). In males, the disorder is usually associated with fetal or neonatal lethality. Occasional surviving males have, in addition to hyperostosis, cardiac, intestinal, and genitourinary malformations. Osteosclerosis in the cranial and facial bones leads to disfigurement and to disability due to pressure on cranial nerves, e.g., deafness. Osteopathia striata is a frequent feature of focal dermal hypoplasia (FDH; 305600).

Although early reports of familial cases of this disorder appeared to suggest autosomal dominant inheritance (see, e.g., Horan and Beighton, 1978 and Konig et al., 1996), reappraisal of the literature (Behninger and Rott, 2000; Rott et al., 2003) and the finding of a molecular basis for the disorder by Jenkins et al. (2009) confirms that the inheritance pattern is X-linked dominant. Affected males who survive have a more severe phenotype than affected females, and sporadic male cases may result from somatic mosaicism (Behninger and Rott, 2000).

Clinical Features

Fairbank (1951) was one of the first to describe the clinical combination of osteopathia stria and cranial sclerosis. Walker (1969) and Jones and Mulcahy (1968) reported affected females.

Winter et al. (1980) observed osteopathia striata with cranial sclerosis in 4 persons spanning 3 generations of a family. The proband was a 29-year-old woman with large head, broad nasal bridge, wide-set eyes, cranial sclerosis, and spina bifida occulta. Osteopathia striata was present since childhood. She also had conductive hearing loss. Her first pregnancy ended in spontaneous abortion; her second pregnancy resulted in a severely affected son who died at 6 days of age. Her third pregnancy resulted in an affected daughter who also had cleft palate. The proband's 60-year-old father was possibly affected, as he had a large head and thickening of the cranial vault. Cleft palate occurred in 1 of 3 unrelated patients seen by McKusick (1986). This patient also had a small ventricular septal defect and right clubfoot. The fingers were unusually long and thin with clinodactyly of distal phalanges 3 to 5. Dental problems were occasioned by the sclerosis of the mandible and maxilla.

Whyte and Murphy (1980) observed osteopathia striata in a woman and her 2 daughters, consistent with X-linked dominant inheritance. All 3 also had a macular, hyperpigmented dermopathy, which included white forelock. Sequential x-rays in 1 daughter showed that bone lesions developed in early childhood.

Konig et al. (1996) described a 4-generation pedigree containing 6 affected individuals, including 5 females, with osteopathia striata with cranial sclerosis. Although the authors suggested autosomal dominant inheritance, the pedigree was also consistent with X-linked dominant inheritance. All the females had a characteristic facial appearance, with macrocephaly, frontal bossing, flat face, hypertelorism, and broad nasal bridge. One had an atrial septal defect and transient facial palsy, and another had cleft palate and mixed hearing loss. The 1 male was the most severely affected, with marked macrocephaly, Pierre Robin sequence (261800) with cleft palate and tracheomalacia. He had severe hypotonia, failure to thrive, and retarded psychomotor development. His facial features included prominent broad forehead, hypertelorism, broad nasal bridge, open mouth, thick lips, malpositioned teeth, microretrognathia, and low-set posteriorly angulated ears. Other features included flexed contraction of the index fingers and several toes. In a follow-up of the family reported by Konig et al. (1996), Perdu et al. (2010) noted that the affected male was alive at age 20 years; moreover, he had a 2-year-old affected brother. Affected family members were found to carry a mutation in the WTX gene (Q271X; 300647.0008).

Pellegrino et al. (1997) described 4 brothers with characteristics of OSCS, 3 of whom died from serious complications. The mother of these children, and her only daughter, had the mildest phenotype, with the typical linear striations in the long bones and macrocephaly. Pellegrino et al. (1997) raised the possibility of X-linked inheritance with mild expression in female relatives. In addition, they recognized absent fibulas, malrotation of abdominal organs, and omphalocele as new manifestations, as well as congenital heart disease.

Bueno et al. (1998) likewise reported a family in which an affected male was stillborn with multiple congenital anomalies, whereas a sister and the mother and maternal grandfather had mild features. They again suggested that this was an example of X-linked OSCS. They reviewed 11 previously reported pedigrees and pointed out that there was no instance of well-confirmed OSCS in a father and son.

Keymolen et al. (1997) described a family with at least 3 affected members. The proposita was 50 years old when first seen for manifestations of multiple sclerosis (126200). She had had extra fingers removed and showed macrocephaly, large forehead, hypertelorism, and left ptosis. X-rays showed basal sclerosis of the skull, a thickened calvaria, and fine linear striations in the long bones. Otosclerosis of the right ear was demonstrated. The concurrence of OSCS and multiple sclerosis in the proposita was considered coincidental. Her daughter had otosclerosis for which bilateral stapedectomy was performed at the age of 21 years. She had a permanent bilateral hearing deficit, irregular, malpositioned upper incisors, macrocephaly, flat nasal bridge, frontal bossing, and hypertelorism. A maternal male cousin was born prematurely with a cleft palate, macrocephaly, dental anomalies, impaired hearing, and delayed speech. He showed frontal bossing, hypertelorism, and bilateral epicanthal folds. X-rays showed a thickened calvaria, increased density of the cranial base, and waveform striations in the body of the mandible but no linear striations in the metaphyses of the femur. The family pattern was consistent with X-linked dominant inheritance. In a follow-up of the family reported by Keymolen et al. (1997), Perdu et al. (2010) noted that the affected male was alive at age 41 years. Affected family members were found to carry a mutation in the WTX gene (300647.0007).

Savarirayan et al. (1997) reported a 4-generation family with 5 affected individuals, all females, that extended the phenotype and lent further support for X-linked dominant inheritance. The proband had multiple congenital abnormalities, including cleft palate, anterior ectopic anus, cutaneous syndactyly of right middle and ring fingers, congenital cardiac defects, and left hydronephrosis with a small right kidney. Skull base sclerosis was present at birth, while metaphyseal striations were only evident on a skeletal survey performed at 2 years of age. Proximal fibular osteolysis was also noted at this time. The child's mother, maternal grandmother, and maternal great-grandmother were also affected, but much less severely so. The mother had a subsequent pregnancy; the fetus was found to have alobar holoprosencephaly, cleft lip and palate, and partial absence of the nose. The pregnancy was terminated, and radiographs showed abnormal sclerosis of the maxilla, mandible, and orbital roofs. The authors suggested that this fetus was also affected, and that holoprosencephaly is a manifestation of OSCS. In affected members of the family reported by Savarirayan et al. (1997), Perdu et al. (2010) found deletion of the WTX gene (300647.0003).

Nakamura et al. (1998) described a 33-year-old Japanese man who had had 5 fractures of the humerus, tibia, and femur as a result of mild traumatic incidents that occurred between the ages of 18 and 33 years, and also had the residual of rib fractures without apparent trauma, demonstrable on radiographs. He had short stature (-2.2 SD), and radiographic evaluation showed cranial sclerosis, longitudinal striations in the metaphyses of the femur and tibia, fan-like striation in the ileum, metaphyseal widening in the femur and tibia, and sclerosis of the ribs. Blood chemical findings, including serum calcium, phosphorus, and alkaline phosphatase, were normal. Biopsy from the ileum showed thick trabeculae composed of woven bone. The authors stated that the coexistence of osteopathia striata, cranial sclerosis, metaphyseal undermodeling, and bone fragility had not been recognized previously, but the disorder may be the same as osteopathia striata with cranial sclerosis, or hyperostosis generalisata with striations. There was no family history of a similar disorder.

Lazar et al. (1999) described a 27-year-old man with OSCS. He had multiple congenital abnormalities including cleft palate, cleft lip, hypertelorism, flat nasal bridge, and clubfeet. He also had mild intellectual impairment. The head was enlarged with prominent occipital bony protrusion. He had micrognathia and was unable to open his mouth fully because of ankylosis of the temporomandibular joints. Hearing was decreased bilaterally.

Particularly convincing evidence for X-linked dominant inheritance was provided by Viot et al. (2002) who reported 10 new cases of OSCS, including 2 sporadic cases and 3 families, with an excess of affected females (9F/1M). Phenotypic variability was observed, as well as several unusual findings. Hirschsprung disease, Pierre Robin sequence, coronal craniostenosis, and laryngotracheomalacia were associated with a poor prognosis. The X-inactivation pattern of peripheral blood lymphocytes in a mildly affected mother and her severely affected son demonstrated nonrandom X inactivation in the mother. This finding, in combination with a sex ratio in favor of females and an increased morbidity and mortality in males, was highly suggestive of X-linked dominant inheritance.

Rott et al. (2003) reported on an affected family with typical OSCS in the mother, a maternal aunt, and the grandmother, and multiple severe malformations in the son. He was affected by cranial sclerosis with frontal bossing, conductive hearing impairment, cleft palate, thoracic dysplasia, mesenterium commune with nonrotation of the gut, anal atresia, bilateral cutaneous syndactyly of third and fourth fingers, duplication of the distal phalanx of the second and third fingers on the right, bilateral fibular aplasia with clubfeet, developmental retardation, epileptic seizures, hypothyroidism, and hypertrophic pyloric stenosis. In one informative carrier woman, the X-inactivation pattern in peripheral leukocytes was random.

Ward et al. (2004) provided a comprehensive description of a skeletal phenotype in a French Canadian girl with a moderate to severe form of sporadic OSCS. Multiple medical problems, including anal stenosis and the Pierre-Robin sequence, were evident in the first few years of life. At 14 years, she was fully mobile with normal intellect and stature. She suffered chronic lower extremity pain in the absence of fractures, as well as severe headaches, unilateral facial paralysis, and bilateral mixed hearing loss. The radiologic and bone histologic findings were described.

Perdu et al. (2011) reported a boy and his mother with osteopathia striata with cranial sclerosis confirmed by genetic analysis (C143X; 300647.0006). The mother, who was heterozygous for the mutation, had macrocephaly, a long face, a long philtrum, thin lips, narrow palate, mild scoliosis, and a mild asymmetry of the legs. Radiographic studies showed cranial sclerosis and striations of the tubular bones. Her 17-year-old son had a severe phenotype, but had survived. He had severe mental retardation, seizures, mixed hearing loss, severe cranial sclerosis with dolichocephaly, atrial septal defect, patent ductus arteriosus, and intestinal malrotation. Dysmorphic facial features included high forehead, hypertelorism, downslanting palpebral fissures, broad nasal tip, cleft lip and palate, dysplastic low-set ears, dysplastic teeth, and short neck. Brain imaging showed ventricular dilatation and hypoplasia of the corpus callosum. Radiographs showed short, broad clavicles, proximal fibular hypoplasia, and scoliosis, but no clear metaphyseal striations of the tubular bones. Perdu et al. (2011) also reported an unrelated family in which a 21-week-old male fetus had severe hypoplastic left heart and bilateral fibula aplasia. Postmortem examination showed upturned nasal tip, long philtrum, micro- and retrognathia, low-set ears, and intestinal malrotation. His mother had a large forehead, hypertelorism, flat face, high-arched palate, broad nasal bridge, hearing deficits, learning disabilities, cranial sclerosis, and metaphyseal striations of the long bones. In a review of the literature, Perdu et al. (2011) noted the unpredictability of male survival in this disorder, and concluded that affected males rarely have striations of the long bones.

Holman et al. (2011) reviewed the features of 6 males with severe OSCS, 4 of whom had previously been reported, and 4 males with mild OSCS, 2 of whom had previously been reported. The patients with the mild form were alive at ages 17 to 26 years. All patients had a characteristic facial appearance with macrocephaly, broad forehead with frontal bossing, broad depressed nasal bridge, hypertelorism, and low-set ears. There was a high prevalence of palatal abnormalities. Sclerosis of the peripheral skeleton was more marked than that in females, but affected males had no metaphyseal striations, except in those with a mosaic mutation, where striations are presumably the result of differential lyonization. Patients with severe OSCS tended to have bilateral absence of the fibulae, duplication of phalanges, omphalocele, kidney malformations, and cardiac defects. Two patients had nephrogenic rests, which may be a precursor of Wilms tumor. Patients with milder OSCS had short stature, lumbar lordosis, and contractures; 1 had a progressive proximal myopathy reminiscent of nemaline myopathy.

Other Features

Kornreich et al. (1988) reported a 21-month-old female first evaluated because of right facial nerve palsy of 2 days' duration. At the age of 12 months she had suffered similar facial palsy, which had gradually subsided over the following 5-month period. The patient was an isolated case in the family, but the parents were 'third-grade' cousins.

Clementi et al. (1993) observed reduction in the visual fields related apparently to narrowing of optic foramina in a girl with fully expressed osteopathia striata with cranial sclerosis.

Inheritance

In an evaluation of the literature on osteopathia striata with cranial sclerosis, Behninger and Rott (2000) concluded that the pattern of inheritance was most consistent with X-linked dominant, and not autosomal dominant, as had been suggested. The authors noted that more affected females had been reported, that affected males have a more severe phenotype with associated mortality, that there has been no proven father-to-son transmission, and that osteopathia striata is a feature of focal dermal hypoplasia (FDH; 305600), which is an X-linked disorder.

Rott et al. (2003) reviewed the multiple malformations that occur in hemizygous males who are offspring of mothers with osteopathia striata (19 sons of 13 mothers). They concluded that there was no reason to assume the existence of an autosomal dominant variant of this disorder that is clearly X-linked in most cases. One instance of father-son transmission in 1 family had been assumed by Horan and Beighton (1978), but was not documented by x-ray examination.

Mapping

Rott et al. (2003) stated that preliminary linkage studies suggested that the OSCS locus maps to Xp11.4-p11.22.

Molecular Genetics

Jenkins et al. (2009) identified a female proband with severe hyperostosis of the skull and appendicular skeleton, marked developmental delay, and seizures. The skeletal phenotype was consistent with OSCS. DNA analysis revealed a de novo deletion greater than 2.1 Mb on chromosome Xq11.1. Of the 4 annotated genes within the deleted region, Jenkins et al. (2009) considered WTX as a potential monogenic contributor to the skeletal phenotype because of its role as a repressor of canonical WNT signaling. Jenkins et al. (2009) studied 19 probands with OSCS and their affected relatives. Of the 5 males, 3 were midgestation fetuses with multiple malformations (omphalocele, limb patterning defects, cardiac and genitourinary anomalies) incompatible with survival beyond the neonatal period. Two surviving males (aged 17 years and 23 years) had, in addition to sclerosing skeletal dysplasia, learning disability, cardiomyopathy, skeletal myopathy, and central nervous system malformations. Sequencing of WTX revealed mutations in 18 of 19 unrelated families. All mutations either deleted the entire gene or were nonsense or frameshift mutations. Mutations segregated with the phenotype in all familial cases. At least 10 mutations arose de novo. Three recurrent mutations (R353X, 300647.0004; R358X, 300647.0005; and whole-gene deletions) were identified and these had been observed as somatic mutations in Wilms tumors (see 194070). All point mutations identified clustered in the 5-prime region of WTX; mutations leading to lethality in males were located more 5-prime than those associated with survival.

In affected members of the families reported by Savarirayan et al. (1997), Keymolen et al. (1997), and Konig et al. (1996), Perdu et al. (2010) identified a deletion of the WTX gene and 2 mutations in the WTX gene, respectively (300647.0003; 300647.0007; 300647.0008). In addition, 4 unrelated females with the disorder were found to carry the recurrent R358X mutation (300647.0005).

In a 17-year-old boy with osteopathia striata with cranial sclerosis, Perdu et al. (2011) identified a hemizygous truncating mutation in the 5-prime end of the gene (C143X; 300647.0006). The mutation was predicted to result in a very short truncated form of the WTXS1 isoform and most likely complete absence of a functional protein. Perdu et al. (2011) noted that although this mutation occurred in the 5-prime region of the gene, which Jenkins et al. (2009) postulated would be correlated with reduced survival, the patient had unusually long survival. The report indicated that this genotype/phenotype correlation is not absolute.

Genotype/Phenotype Correlations

Jenkins et al. (2009) suggested a putative genotype/phenotype correlation for OSCS: mutations producing a WTXS1 isoform with an intact phosphatidylinositol (4,5)-bisphosphate binding domain and APC-binding domain-1 resulted in survival of males, whereas mutations causing truncation of WTXS1 5-prime to these domains resulted in male lethality. The presence of intact WTXS2 was not protective against the disease, most likely because the WTXS2 isoform is not localized to the plasma membrane. However, Perdu et al. (2010) and Perdu et al. (2011) reported at least 2 surviving males with mutations in the 5-prime region of the gene, indicating that the hypothesis presented by Jenkins et al. (2009) is not absolute.

Holman et al. (2011) found that 5 male patients with severe OSCS had truncating WTX mutations 5-prime to the beta-catenin binding domain; the sixth patient had a whole gene deletion. In contrast, 4 male patients with a milder form of OSCS and survival into the second or third decade had mutations 3-prime to the beta-catenin binding domain.

History

Horan and Beighton (1978) concluded that the disorder is autosomal dominant. However, several studies provided compelling evidence for X-linked dominant inheritance.

Rucker and Alfidi (1964) described a man with sclerotic bone disease which had the additional feature of striations. His father and grandfather were said to have the same disorder; the father died of severe aortic stenosis.