Characterization of a complex chromosomal rearrangement in a patient with a typical catlike cry and no other clinical findings of cri-du-chat syndrome

We report on the clinical, cytogenetic, and molecular cytogenetic findings in a 4-year-old girl who was evaluated for developmental delay and a catlik e cry from birth, No other findings of cri-du-chat syndrome were present. K aryotype analysis demonstrated a de novo deletion and inverted duplication of the 5p region. The abnormality was confirmed and further defined by deta iled FISH analysis using cosmid and lambda phage clones previously mapped t o distinct regions of 5p, The analyses documented deletion of 5p15.3-->pter and an inverted duplication of 5p14-->5p15.3. The deleted segment on 5p co ntains the region implicated in the isolated catlike cry feature of the cri -du-chat syndrome, confirming that the genes involved in the catlike cry ma p to the distal end of 5p, Except for the catlike cry and possibly the deve lopmental delay that may be due to the deletion of 5p, the duplication of 5 p14-->5p15.3 in this patient did not present with additional anomalies. Thi s study further demonstrates the usefulness of the molecular cytogenetic ap proach for characterizing complex chromosome rearrangements. Such analyses of patients with an isolated catlike cry can avoid an incorrect diagnosis o f the cri-du-chat syndrome, which is associated with a more severe prognosi s. (C) 1999 Wiley-Liss, Inc.