Search for a rare disease
Other search option(s)
A rare congenital limb malformation characterized by bifid femur, absent or hypoplastic tibia and ulna with limb shortening, oligodactyly, and ectrodactyly.
ORPHA:1986Classification level: Disorder
Approximately 200 cases have been reported worldwide.
The malformation presents with congenital aplasia/hypoplasia of the tibia, bifurcation of the distal femur, more commonly unilateral, accompanied by pre-axial oligodactyly or monodactyly of the feet. There is oligodactyly and ectrodactyly, often associated with an abnormality of the ulna. The pattern is frequently asymmetric. Occasionally other abnormalities can be present, namely congenital heart defects, cleft lip and palate and tracheo-oesophageal fistula.
The etiology remains unknown. In two Japanese patients, a duplication and a triplication of a 210 Kb chromosomal segment in 17p13.3, including BHLHA9, has been detected, and considered a susceptibility factor for the limb malformation.
Diagnosis is based on clinical and radiological findings.
Differential diagnoses includes hypoplastic tibiae-postaxial-polydactyly syndrome and split hand foot malformation syndromes.
Prenatal diagnosis can be performed by ultrasound scans in the second trimester of pregnancy.
Whilst the pattern of inheritance is currently unknown, autosomal dominant and autosomal recessive inheritance models have been suggested.
Management and treatment
Patients should be offered orthopedic and reconstructive surgery (involving prosthetics) and regular monitoring.
Life expectancy is not reduced but, in the absence of treatment, the functional prognosis is poor.