OBJECTIVETo explore the clinical features and genomic abnormality of a patient with Coffin-Siris syndrome.

METHODSMicrodeletion and microduplication were detected with chromosomal microarray analysis (CMA) and verified with real-time quantitative PCR.

RESULTSThe patient, a 6-month-old boy, featured global development delay, thick eyebrows, low frontal hairline, long eyelash, flat nasal bridge, hypotonia, difficulty in turning over, over stretching of head, and hypoplatic nails. He could not stand stability or actively grasp. He also has characteristics of rickets. Chromosome karyotype of the patient was normal. Genomic analysis has detected a 1.3 Mb deletion in 6q25.3 region encompassing the ARID1B gene. Neither of his parents was found to harbor the same deletion.

CONCLUSIONThe 6q25.3 microdeletion probably underlies the Coffin-Siris syndrome in this patient, and rickets may be part of its clinical spectrum.