Ankyloblepharon-Ectodermal Defects-Cleft Lip/palate Syndrome

An ectodermal dysplasia syndrome with defining features of ankyloblepharon filiforme adnatum (AFA), ectodermal abnormalities and a cleft lip and/or palate.

Epidemiology

Ankyloblepharon-ectodermal defects-cleft lip/palate syndrome (AEC syndrome) prevalence is unknown.

Clinical description

A history of skin erosions, especially of the scalp neonatally is typical. Congenital erythroderma occurs in 78%. Skin erosions often persist intermittently for many years, evolving into alopecia and cutaneous scarring of the skin. Wound healing appears to be delayed. Other prevalent skin manifestations include hyperpigmentation and/or hypopigmentation, often reticulated, and palmar and plantar changes with effaced dermatoglyphics. Nail changes are universal and variable and include hyperconvexity, pseudoptyergium and frayed distal margin with nail plate resorption. Hypotrichosis is common and hair is thin, brittle, wiry and uncombable. Mild hypohidrosis is always present. Nearly all cases have clefting abnormalities, ranging from submusous cleft palate, to soft and/or hard cleft palate, cleft lip or a combination. Other oroauditory findings include recurrent otitis media, canal stenosis and over 90% have a conductive hearing loss associated with a delay of speech development. AFA affects most neonates (70%) but is not always evident as these may autolyse or be lysed by a healthcare provider applying ophthalmic antibiotic ointment at birth. Eyes often are deficient of lacrimal puncta. In childhood, other facial features become more apparent and include broad nasal root, hypoplastic alae nasi, short philtrum, thin vermillion border, maxillary hypoplasia and small mandible. Over time, cone-shaped teeth and hypodontia become evident. Other anomalies are limb changes with syndactyly of fingers and toes most common, hypospadias (males 78%) and trismus (less frequently described). Failure to thrive, growth delay and gastrointestinal issues are also common.

Etiology

AEC is an autosomal dominant condition caused by pathogenic (usually missense) changes in the Tumor suppressor gene TP63. Over 4/5th of the reported pathogenic variants occur in the sterile alpha motif (SAM) domain, and about 1/5th occur in the transactivation inhibitory (TI) domain of TP63.

Diagnostic methods

Clinical features can be diagnostic. Light or scanning microscopy of the hair in combination with genetic testing may ascertain diagnosis.

Differential diagnosis

Differential diagnosis may include epidermolysis bullosa simplex, disorders of cornification, CHAND syndrome and hypohidrotic ectodermal dysplasia. Allelic disorders include Acro-dermal-ungual-lacrimal-tooth (ADULT) syndrome, ectrodactyly-ectodermal dysplasia clefting (EEC) syndrome, limb-mammary syndrome and split hand/foot malformation type 4. AEC is generally distinguished from these other disorders by clinical features (particularly scalp erosions) as well as the location of the TP63 change. The Rapp-Hodgkin syndrome is not a separate disease entity, but is now considered part of the disease spectrum of AEC syndrome.

Antenatal diagnosis

In case of family history, prenatal diagnosis is possible by genetic testing of amniocentesis or chorionic villus sampling.

Genetic counseling

AEC syndrome follows an autosomal dominant inheritance pattern. About 70% of cases are caused by a de novo change in TP63. In case of family history, genetic counseling is recommended. Genetic counseling should be proposed to individuals having the pathogenic variants, informing them that there is 50% risk of passing the mutation to offspring.

Management and treatment

AFA and cleft palate may require surgical intervention, as well as dental abnormalities requiring prosthetics. Efforts to prevent secondary infections in skin erosions comprise gentle wound care and dilute bleach soaks. Secondary infections should be cultured and treated appropriately. Extra care should be taken to avoid complications in infants with severe skin erosions. Extensive grafting procedures are not recommended. Hearing loss, growth and gastrointestinal problems should be monitored regularly. Gastrostomy is common. Psychological consequences of ectodermal defects should be addressed.

Prognosis

Overall prognosis is good with most having normal life expectancy. Unfortunately infants with extensive skin erosions are at risk of premature death due to complications including sepsis and fluid/electrolyte abnormalities. Quality of life and psychosocial functioning is often mildly but variably impacted.