Patient with a 22q11.2 deletion with no overlap of the minimal DiGeorge syndrome critical region (MDGCR)

The apparent lack of genotype/phenotype correlation in patients with the Di George anomaly and velocardiofacial syndrome (DGA/VCFS; the "22q11 deletion syndrome") indicates a complex genetic condition. Most cases, whatever the phenotype, have a 1.5-3 Mb chromosomal deletion that includes the minimal DiGeorge critical region (MDGCR). Another potential critical region on 22q1 1 has been suggested based on two patients with distal deletions outside th e MDGCR. We report on a patient with a VCFS phenotype who has a deletion, m apped by short tandem repeat polymorphic loci and fluorescence in situ hybr idization analysis, distal to and not overlapping the MDGCR. This patient i s deleted for several genes, including the T-box 1 gene (TBX1; a transcript ion regulator expressed early in embryogenesis) and catechol-O-methyltransf erase (COMT; involved in neurotransmitter metabolism). We discuss the role these two genes may play in the clinical phenotype of the patient. Am. J. M ed. Genet. 86:27-33, 1999. (C) 1999 Wiley-Liss, Inc.