Phenotypic overlap of the BBB and G syndromes.

Three males with similar malformations including hypertelorism, telecanthus, cleft lip and palate, and hypospadias, have been evaluated. One also had a laryngotracheoesophageal cleft and therefore was considered to have the G syndrome. The other two had no stridor, aspiration, or difficulty swallowing, and were considered to have the BBB syndrome. Both disorders are associated with multiple malformations and can be most readily distinguished by the presence of laryngoesophageal abnormalities in the G syndrome and differences in facial features evident later in childhood. The BBB syndrome appears to be inherited as an X-linked disorder with the affected female showing only telecanthus and hypertelorism. The G syndrome exhibits autosomal dominant inheritance with males more severely affected, although a few few females have had serious malformations in addition to telecanthus and hypertelorism. In the family with the G syndrome evaluated for this report, the mother of the affected infant had telecanthus, hypertelorism, and anosmia, the latter a feature not previously noted in this disorder.