Dominant inheritance of cleft palate, microstomia and micrognathia--possible linkage to the fragile site at 16q22 (FRA16B).

We report a family in which a father and his three children are affected with microstomia, micrognathia and partial or complete cleft of the hard and soft palate. The probands were non-identical twins, a boy and a girl, both noted to have the above features soon after birth. Their father was diagnosed with a submucous cleft of the palate at the age of 4 years and their older brother has milder facial features and a bifid uvula. All affected family members were demonstrated to have a fragile site on chromosome 16q22 but otherwise normal karyotypes. Of interest is a previously described family with autosomal dominant inheritance of U-shaped cleft palate, microstomia, micrognathia and oligodontia where all affected members were shown to have the fragile site at 16q22 in a proportion of their cells [Bettex et al. (1998) Eur J Pediatr Surg 8:4-8]. We propose that these two conditions are the same and represent a distinctive syndrome involving aberrant orofacial development that may be linked to the fragile site at 16q22.