Sir.—In the April issue of the Journal, M. Michael Cohen, Jr., DMD (127:597, 1974) brought out some very important points with regard to genetic counseling in holoprosencephaly. Some additional information on the mother of one of the patients of Patel et al1 may be of interest. They correctly noted the presence of orbital hypotelorism, but in addition, the mother had a single, centrally placed medial incisor (Figure). No teeth had been lost due to disease or injury. This sign may be an additional piece of evidence suggesting an autosomal dominant gene with variable expressivity and, thus, the recurrence risk in subsequent pregnancies may be substantial.
LOWRY RB. Holoprosencephaly. Am J Dis Child. 1974;128(6):887. doi:10.1001/archpedi.1974.02110310135030