RESUMEN
OBJECTIVE To analyze the clinical features and genetic mutations in a neonate with atypical Cri-du-chat syndrome, whom only featured with weak cry but had no dysmorphic facial features and congenital heart disease. METHODS G-banding karyotyping was performed on the child and her parents. The result was validated by fluorescence in situ hybridization (FISH). Chromosome microarray (CMA) was used to further delineate the mutation. RESULTS G-banding analysis suggested that the child had a karyotype of 46,XX,del(5)(p14p15), while both of his parents had a normal karyotype. FISH confirmed the absence of D5S23 and D5S721 at 5p15.2. A 25.7 Mb deletion was detected in the 5p15.33p14.1 region by CMA. CONCLUSION The phenotype of Cri-du-chat syndrome can vary significantly among patients, particularly in neonates, and can be easily mis-diagnosed. Combined cytogenetic and molecular analysis can identify the missing fragments with greater precision.