Mcy. Ng et al., Familial early-onset type 2 diabetes in Chinese patients - Obesity and genetics have more significant roles than autoimmunity, DIABET CARE, 24(4), 2001, pp. 663-671
OBJECTIVE - We examined the prevalence of different Forms of diabetes in Ho
ng Kong Chinese patients with familial early-onset type 2 diabetes and comp
ared their clinical features with patients with familial late-onset type 2
diabetes.
RESEARCH DESIGN AND METHODS - A total of 145 young patients with early-onse
t diabetes (age and age at diagnosis less than or equal to 40 years) and a
family history of diabetes were studied. They were screened for mutations i
n the genes encoding glucokinase, hepatocyte nuclear factor (HNF)-4 alpha,
and HNF-1 alpha. The mitochondrial DNA A -->G at nucleotide 3243 (mt3243) a
nd amylin S20G mutations were studied, and antibodies to GAD (anti-GADs) we
re also examined.
RESULTS - The prevalence of putative diabetogenic gene mutations and autoim
mune markers were 4% For glucokinase. 0% for HNF-4 alpha. 5% For HNF-1 alph
a, 3% for mt3243, 2% For amylin S20G, and 4% Eor anti-GAD. Compared with La
te-onset patients. the patients with early-onset diabetes had a higher prev
alence of a parental history of diabetes and were generally more obese. Whe
n classified by obesity indexes (BMI and waist circumference), the obese pa
tients, especially those with early-onset diabetes, had a clustering of car
diovascular risk Factors and increased rates of retinopathy and albuminuria
.
CONCLUSIONS - Genetic factors (up to 14%) and obesity (55%) play more signi
ficant roles than autoimmunity (SB) in familial type 2 diabetes in young Ch
inese patients. The significance of obesity-related genes and other gene-ge
ne and gene-environment interactions in these young patients remains to be
determined.