Heterogeneity and variability in the oral-facial-digital syndromes.

The oral-facial-digital syndromes are a heterogeneous group of conditions sharing oral, facial, and digital anomalies. Based on more or less subtle clinical differences, at least seven causally different entities can be identified in this group. These include 1) oral-facial-digital syndrome (OFDS) I; 2) Mohr syndrome (OFDS II); 3) OFDS III; 4) OFDS with tibial anomalies (OFDS IV); 5) Thurston syndrome; 6) Varadi syndrome; and 7) Whelan syndrome. However, since differentiation between these entities is based on clinical findings, this classification should be viewed as tentative until more definitive methods are available.