EVIDENCE FOR A DISTINCT REGION CAUSING A CAT-LIKE CRY IN PATIENTS WITH 5P DELETIONS

The cri-du-chat syndrome is a contiguous gene syndrome that results fr om a deletion of the short arm of chromosome 5 (5p). Patients present with a cat-like cry at birth, which is usually considered diagnostic o f this syndrome. Additional features of the syndrome include failure t o thrive, microcephaly, hypertelorism, epicanthal folds, hypotonia, an d severe mental retardation. We report on four families in which patie nts with 5p deletions have only the characteristic cat-like cry, with normal to mildly delayed development. The precise locations of the del etions in each family were determined by FISH using lambda phage and c osmid clones. All of the deletion breakpoints map distal to a chromoso mal region that is implicated with the facial features and severe ment al and developmental delay in the cri-du-chat syndrome. DNA clones map ping in the chromosomal region associated with the cat-like cry featur e will be useful diagnostic tools. They will allow for the distinction between 5p deletions that will result in the severe delay observed in most cri-du-chat syndrome patients and those deletions that result in the isolated cat-like cry feature, which is associated with a better prognosis.