Familial DiGeorge syndrome and associated partial monosomy of chromosome 22

Abstract

Partial monosomy of 22q due to an unbalanced 4;22 translocation was seen in a 2-month-old male with Type I truncus arteriosus, dysmorphic features, and T-cell abnormalities. The family history revealed a previous sib with Type I truncus arteriosus, thymic aplasia, and parathyroid hypoplasia noted on postmortem examination, consistent with DiGeorge syndrome. Evaluation of the asymptomatic mother of these two patients revealed partial T-cell deficiency and the same unbalanced translocation with deletion of proximal 22q11. These findings provide further evidence that some cases of complete or partial DiGeorge syndrome are associated with monosomy of the proximal long arm of chromosome 22, and they may explain many, if not all, familial cases of the syndrome.

A case of incomplete DiGeorge syndrome associated with partial monosomy 22q11.1 due to maternal 14;22 translocation

“…reported an association between DiGeorge syndrome and a deletion in chromosome 22. Subsequently other reports of a similar association have been published (Kelley et al, 1982;Greenberg et al, 1984;Pong et al, 1985;Schwanitz and Zerres, 1987;Faed et al, 1987). Using high-resolution banding analysis, we report a patient with incomplete DiGeorge syndrome, who showed a deletion of 22ql 1.1 band.…”

DiGeorge Syndrome with Graves' Disease. A Case Report.

“…It also affects other portions of the pharyngeal pouch besides the third and fourth pharyngeal pouch, and abnormal migration of neural crest cells is thought to be the cause of this anomalies [l, 2]. More than 95% of the subjects reveal the deletion by translocation of the 22nd chromosome long arm q 11 [3][4][5][6][7][8][9][10][11][12][13][14][15] . The initial symptom is tetany due to hypocalcemia within 24-48 hours after birth, with symptoms associated with immune defects appearing later.…”

Recent advances in developmental genetics: Growth factors and morphogens

“…However, the phenotype of Hox 1.5 absence differs somewhat in the cardiac abnormalities found and includes many more abnormalities than DiGeorge, but since the mice die in a few hours, comparisons to children who survive long enough to be diagnosed may not be appropriate. Perhaps the biggest discrepancy between the two is that DiGeorge is associated with deletions or microdeletions of 22ql.l in up to 50% of patients (Augusseau et al, 1986;De la Chapelle et al, 1981;Greenberg et al, 1986;Kelley et al, 1982;Schwanitz and Zerres, 1984;Scambler et al, 1991;Halford et al, 1993), while the human equivalent of Hox 1.5 maps to chromosome 7.…”