Genetics and Clinical Characteristics of PPARγ Variant-Induced Diabetes in a Chinese Han Population.

OBJECTIVES

variants cause lipodystrophy, insulin resistance, and diabetes. This study aimed to determine the relationship between genotypes and phenotypes and to explore the pathogenesis of diabetes beyond this relationship.

METHODS

exons in 1,002 Chinese patients with early-onset type 2 diabetes (diagnosed before 40 years of age) were sequenced. The functions of variants were evaluated by assays. Additionally, a review of the literature was performed to obtain all reported cases with rare variants to evaluate the characteristics of variants in different functional domains.

RESULTS

Six (0.6%) patients had variant-induced diabetes (PPARG-DM) in the early-onset type 2 diabetes group, including three with the p.Tyr95Cys variant in activation function 1 domain (AF1), of which five patients (83%) had diabetic kidney disease (DKD). Functional experiments showed that p.Tyr95Cys suppresses 3T3-L1 preadipocyte differentiation. A total of 64 cases with damaging rare variants were reported previously. Patients with rare variants in AF1 of had a lower risk of lipodystrophy and a higher rate of obesity than those with variants in other domains, as confirmed in patients identified in this study.

CONCLUSION

The prevalence of PPARG-DM is similar in Caucasian and Chinese populations, and DKD was often observed in these patients. Patients with variants in the AF1 of had milder clinical phenotypes and lack typical lipodystrophy features than those with variants in other domains. Our findings emphasize the importance of screening such patients genetic testing and suggest that thiazolidinediones might be a good choice for these patients.