ISOLATION OF A GENE EXPRESSED DURING EARLY EMBRYOGENESIS FROM THE REGION OF 22Q11 COMMONLY DELETED IN DIGEORGE-SYNDROME

DiGeorge syndrome (DGS) is one of several syndromes associated with de letions within the proximal long-arm of chromosome 22. The region of c hromosome 22q11 responsible for the haploinsufficiency syndromes (the DiGeorge Critical Region or DGCR) has been mapped using RFLPs, quantit ative Southern blotting and FISH. Similar deletions are seen in the ve lo-cardio-facial syndrome (VCFS) and familial congenital heart defects . It is not known whether the phenotypic spectrum is the result of the hemizygosity of one gene or whether it is a consequence of contiguous genes being deleted. However, the majority of patients have a large ( > = 2Mb deletion). In this paper we report the isolation of a gene, la b name T10, encoding a serine/threonine rich protein of unknown functi on which maps to the commonly deleted region of chromosome 22q11. Stud ies in the mouse indicate that it maps to MMU16 and is expressed durin g early embryogenesis. Although not mapping within the shortest region of overlap for DGS/VCFS, and therefore not the major gene involved in DGS, the expression pattern suggests that this gene may be involved i n modifying the haploinsufficient phenotype of hemizygous patients.