DELETION MAPPING BY FISH WITH BACS IN PATIENTS WITH PARTIAL MONOSOMY 22Q13

Patients with deletions in 22q13 are known to have phenotypic features that include normal or accelerated growth, large hands and feet, hypo tonia, delayed psychomotor development and mild facial dysmorphism. To date, very few cases have been investigated by detailed molecular gen etic analysis, We have analyzed three new patients with terminal delet ions in 22q. We compared the cytogenetic observations with molecular d ata assessed by fluorescence in situ hybridization and an array of cha racterized bacterial artificial chromosome recombinants, The shortest region of deletion overlap is localized in 22q13.2-qter distal to the marker D22S94, but the telomeric repeat in the deleted chromosome appe ars to remain intact. When parental alleles were investigated in two o f the three patients, the aberrant homolog was found to be of paternal origin in both cases. Although the deleted region still spans >20 cM, molecular analysis of additional patients and screening for new genes might help in elucidating candidate genes connected with the dysmorph isms defined by deletions of 22q13.