The Moebius syndrome: aetiology, incidence of mental retardation, and genetics.

We read with interest the proposal of a new autosomal recessive syndrome by Hurst etal Med Genet 1989;26:407-9) based on the description of two sibs with ASD, VSD, developmental delay, poor growth, microcephaly, low set, posteriorly rotated ears, and other dysmorphic features. The brother had choanal stenosis and the sister was also suspected to have choanal stenosis, but this was not proven. The authors eliminated CHARGE association because they concluded that it is a sporadic defect. However, there have been several reports of familial CHARGE association, also known as CHARGE syndrome. Metlay et all reported one such family and reviewed eight others in published reports. Of these, six appeared most likely to be autosomal dominant, two to be auto- somal recessive, and one involved affected monozygotic twins and so could be either dominant or recessive. Two additional sets of affected mono- zygotic twins have been reported,2 3 as well as another family that appears to represent autosomal recessive inheritance.4 Thus, CHARGE association appears to be aetiologically hetero- geneous with most cases sporadic but a small yet significant percentage familial.