The G and BBB syndromes: case presentations, genetics, and nosology

Hypertelorism and hypospadias are described in four unrelated boys; bilateral cleft lip and cleft palate were also present in two of the boys and mild mental retardation in another. These features are compatible with both the G and BBB syndromes. When present, laryngotracheoesophageal anomalies or respiratory and swallowing difficulties are characteristic features of the G syndrome; otherwise facial features may be useful in distinguishing the G and BBB syndromes. Cases 1 and 2 had anteverted nares and a broad and flat nasal bridge, and Case 1 had shortened palpebral fissures, all consistent with the G syndrome. In contrast, Cases 3 and 4 had a high and broad nasal bridge as previously described in the BBB syndrome. The father of Case 1 had mild hypertelorism and first-degree hypospadias, demonstrating autosomal dominant inheritance in the G syndrome. The mothers of Cases 2, 3, and 4 all had mild hypertelorism consistent with autosomal dominant inheritance and partial male-sex limitation, as previously proposed for both the G and BBB syndromes.