Longitudinal analysis of lymphocyte function and numbers in the first yearof life in chromosome 22q11.2 deletion syndrome (DiGeorge syndrome/velocardiofacial syndrome)

Chromosome 22q11.2 deletion syndrome is a common syndrome typically consist ing of variable cardiac defects, hypoparathyroidism, developmental delay, a nd immunodeficiency. The hemizygous deletion has variable effects on the im mune system even within the same kindred, and the extent of the immunodefic iency is difficult to predict. Some patients have shown improvement over ti me; however, this is the first prospective longitudinal study of the dynami c nature of the immunodeficiency. Nineteen patients were studied prospectiv ely between 1994 and 1997. The results of the newborn immunologic studies i n the chromosome 22q11.2 deletion group were significantly different from t hose of a group of newborns with cardiac disease due to other causes. Perip heral blood T-cell numbers were decreased in the chromosome 22q11.2 deletio n group, although T-cell function was largely preserved. The group as a who le demonstrated few changes in the first year of life, but a subset of pati ents with markedly diminished T-cell numbers did demonstrate improvement. T herefore, improvement in peripheral blood T-cell counts is variable in chro mosome 22q11.2 deletion syndrome. The patients with the lowest T-cell count s improved the most in the first year of life.