Further evidence for preaxial hallucal polydactyly as a marker of diabetic embryopathy.

Maternal diabetes has an established aetiological link with developmental abnormalities, and the prevalence of major congenital malformations in the offspring of affected women is approximately 4-8%, compared to the general population risk of about 3%. Hallucal polydactyly, particularly with an unusual proximal placement of the extra digit, has been reported as a distinctive anomaly in diabetic embryopathy. We report on a child of a diabetic mother with this unusual form of hallucal polydactyly, together with other skeletal anomalies, confirming that this malformation is a useful clinical marker for the diagnosis of diabetic embryopathy.