Objective: To explore the clinical features and genetic etiology for a neonate with Smith-Magenis syndrome (SMS).
Methods: Copy number variation sequencing (CNV-seq) was applied to the neonate and his parents, and the genotype-phenotype correlation was analyzed.
Results: On the second day after birth, the neonate had presented with pathological jaundice and immunodeficiency. Cranial MRI revealed ventricular enlargement and enlargement of cisterna magna. At 3 months, the infant has presented with square face, prominent forehead, deep-set eyes, hypertelorism, palpebral fissure upward and button noses. Genetic testing showed that he had carried a 2.9 Mb deletion in 17p11.2 region, seq[GRCh37] del(17)(p11.2)(chr17:16 836 379-19 880 992). The same deletion was not found in either parent.
Conclusion: SMS is mostly diagnosed in child and adulthood, but rarely in neonates. For neonates with SMS, the neurological and behavioral abnormalities have not been shown, but pathological jaundice, CNS abnormalities and immune deficiency may be the characteristics, which require attention of neonatal physicians.