Phocomelia, Schinzel Type

Schinzel phocomelia syndrome, also called limb/pelvis hypoplasia/aplasia syndrome, is characterized by skeletal malformations affecting the ulnae, pelvic bones, fibulae and femora. As the phenotype is similar to that described in the malformation syndrome known as Al-Awadi/Raas-Rothschild syndrome, they are thought to be the same disorder.

Epidemiology

Only a few cases have been described.

Clinical description

Patients have intercalary limb deficiencies (phocomelia sometimes combined with polydactyly, oligodactyly or ectrodactyly), absent or hypoplastic pelvic bones (including sacral agenesis or hypoplasia), skull defects (frequently a defect of the occipital bone with or without meningocele). Additional features may include thoracic dystrophy, unusual facies (dysplastic and large ears, and a high and narrow palate), and genital malformations (Mullerian aplasia, agenesis of the uterus and vagina, micropenis with cryptorchidism). Growth and mental development are normal.

Etiology

A null mutation in the WNT7A gene (3p25) is responsible for this syndrome. It is a severe allelic form of Fuhrmann syndrome.

Diagnostic methods

The limb deficiencies and/or the absent pelvis may be detected by ultrasound.

Genetic counseling

As most of the affected patients were born to consanguineous parents, autosomal recessive inheritance is presumed.

Prognosis

Some of the affected infants died shortly after birth.