Familial third-fourth pharyngeal pouch syndrome with apparent autosomal dominant transmission.

A family is presented in which both siblings and their father had evidence of third-fourth pharyngeal pouch syndrome (DiGeorge syndrome). All three individuals had hypocalcemia and unusual facies. Both infants had truncus arteriosus. One infant had evidence of impaired cell-mediated immunity; the father had a relatively decreased number of T-lymphocytes. The syndrome is uncommon, most cases being isolated, and familial presentations are even rarer. Two recent reports described several affected individuals who also had partial deletions of chromosome 22. Chromosome banding studies in our family were normal. Thus our family demonstrates an autosomal dominant pattern of inheritance, although it cannot be proved that this is a single gene defect. We propose that inasmuch as the presentation of the syndrome is quite varied, thorough family investigation including high-resolution cytogenetic analysis is necessary. Familial cases may be more common and require genetic counseling.