OMIM ID:
Branchiooculofacial Syndrome
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Microphthalmos, or anophthalmia, and an imperforate nasolacrimal duct are the primary ocular features in this syndrome. The nasolacrimal ducts may open onto the skin adjacent to the lacrimal sac. Uveal tract and optic nerve colobomas are present in nearly half of patients. Strabismus is sometimes seen. Cataracts are present in about 25% of patients as well. The lid fissures are often slanted upwards.
Systemic Features
A cleft lip and/or palate are common features. There may be preauricular pits, lip pits, a highly arched palate, and hypodontia. Some individuals have subcutaneous cysts in the scalp. Postauricular cervical branchial and supraauricular defects are often present as well. It is not unusual to see some skin discoloration behind the ears. The nasal bridge is broad, the top of the nose is flattened, and the philtrum is often short. The ears are often enlarged or malformed and in 70% of patients there is some hearing loss which is usually conductive in origin but neurosensory deafness has also been documented. Premature graying of hair is common. Kidney malformations and dysfunction have been documented. Mental function is usually normal. Preaxial polydactyly is an uncommon feature.
Genetics
Inheritance
This is an autosomal dominant disorder resulting from mutations in the TFAP2A gene (6p34.3). Both deletions and insertions have been identified. However, 50-60% of patients have de novo mutations. As in many autosomal dominant disorders there is considerable clinical heterogeneity and few patients have all of the signs.
Pedigree
Autosomal dominant
Autosomal dominant disorders require only one mutation for the disease to be expressed. Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease. It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).
Autosomal dominant inheritance leads to a vertical pattern of transmission