Abstract: Objective? To explore the clinical characteristics and gene mutation characteristics of congenital generalized lipodystrophy (CGL). Methods? Clinical data and genetic results of a twin with CGL were retrospectively analyzed. Results? Both of the twins were male at the age of 4 months old, presented with similar features including the disappearance of adipose tissue throughout the body, hepatosplenomegaly, and a small amount of pigmentation all over the body. Laboratory examination revealed hypertriglyceridemia. DNA extracted from peripheral blood from the elder brother of the twin and from their parents was used for whole exome gene sequencing to identify mutations verified by Sanger sequencing. The results showed that the elder brother had a homozygous mutation of c. 974 dup (p.ile 326 hisfster 12 ) in the BSCL 2 gene, which was classified as pathogenic. Both parents carry a heterozygous mutation of c. 974 dup. Ten members (generation I, II, and III) of the family were tested for this mutation, and the younger brother of the twin was also found a homozygous mutation of c. 974 dup, and his grandmother and grandfather, uncle, and their sibling brother are all carriers of the mutation, which is consistent with the autosomal recessive inheritance. Conclusion? Two cases of identical twins with CGL 2 were reported as the first ones in China.

Key words: congenital generalized lipodystrophy;? BSCL 2 gene;? family analysis