SIM1 gene mutation-associated early onset obesity: a case report and literature review / 中华实用儿科临床杂志

ABSTRACT

Clinical data of a child with SIM1 gene mutation-related obesity who visited Beijing Children′s Hospital, Capital Medical University in February 2022 was retrospectively analyzed.This 5-year-and-4-month-old girl was admitted for early onset obesity.She showed obesity at 29 months old, accompanied by severe obstructive sleep apnea syndrome.The patient and her mother had heterozygous variations in the SIM1 gene.Literature has reported a total of 42 patients with obesity caused by SIM1 gene mutations from different families in the world, and nearly 1/3 of patients had clinical manifestations beyond obesity, such as developmental delay, cognitive and behavioral problems, mild dysmorphic appearance, and neuroendocrine abnormalities.The patient in this study was mainly characterized by early onset obesity.At present, 58 SIM1 gene mutations are found to be related to obesity, which are mostly concentrated in the C-terminal domain.The allele frequency of p. T46R and p. D707H has reached 9.5%; therefore, p.T46R and p. D707H are considered hot spot variations, suggesting that SIM1 gene analysis should be improved for patients with early onset obesity.