Abstract

Opitz G/BBB syndrome is a genetic condition that affects several structures along the midline of the body. The most common features of this condition are wide-spaced eyes (hypertelorism) with structural defects of the larynx, trachea, and/or esophagus causing breathing problems and difficulty swallowing (dysphagia). Some times in males, the urethra opening on the underside of the penis (hypospadias) is observed. Mild intellectual disability occurs in 30% approximately of patients with Opitz G/BBB syndrome (GBBBS), most likely caused by structural defects in the brain. About half of affected individuals also have cleft lip with or without a cleft palate as in this study. Some have cleft palate alone. Heart defects, imperforate anus, and brain defects such as absence of the corpus callosum. Facial abnormalities that may be seen in this disorder include a flat nasal bridge, thin upper lip, and low set ears. There are two forms of Opitz G/BBB syndrome, which are distinguished by their genetic causes and patterns of inheritance. The X-linked form of Opitz G/BBB syndrome is caused by a mutation in a specific gene, MID1, on the X chromosome. Autosomal dominant Opitz G/BBB syndrome is caused by a mutation in an as-yet unidentified gene on chromosome 22. Two chromosomal aberrations in this study were observed in two patients; chromosome duplication 47,XXY and translocation 46,XX t(3;4). However one patient with oral encephalocele presented normal karyotype 46,XY.

Key words: Hypertelorism, cleft lip with or without cleft palate, chromosomes, klinefelter syndrome, chromosomal translocation