Triple genetic variation in the HNF-4alpha gene is associated with early-onset type 2 diabetes mellitus in a philippino family.
Maturity-onset diabetes of the young-type 1 (MODY1) is a form of monogenic type 2 diabetes mellitus (T2DM) with long-term complications due to mutations in the HNF-4alpha gene. The HNF-4alpha gene is involved in hepatic differentiation and expression of genes regulating glucose transport, glycolysis, and lipid metabolism. The abnormal glucose-stimulated insulin secretion in MODY1 subjects may be due to reduced glucose transport and glycolysis. To date, 14 mutations in the HNF-4alpha gene have been identified as a cause of either MODY1 or late-onset type 2 diabetes. So far, no screening has been performed in subjects from the Philippines. We recruited a Philippino family with autosomal dominant early-onset type 2 diabetes and screened the proband for mutations in the genes for HNF-1alpha, GCK, HNF-4alpha, IPF-1, HNF-6, and NGN3. We identified a new missense mutation in exon 5 (V199I) of the HNF-4alpha gene and 2 new single-nucleotide substitutions in intron 4, IVS4-nt4 (G --> A) and IVS4-nt20 (C --> T), all cosegregating with diabetes in the 3 affected available siblings. These variations were not present in 100 normal healthy subjects. Bioinformatic analysis suggests that these variations in the whole, and overall the IVS4-nt4 variation located at splicing site, may affect the splicing potential of intron 4. We have biochemically and clinically characterized the Philippine-1 family. We suggest that the V199I missense mutation located in the ligand binding/dimerization domain of HNF-4alpha contributes to type 2 diabetes in the Philippine-1 family. The intron variations may contribute susceptibility to diabetes.
Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA.
Claudia
C
Gragnoli
Guido
G
Menzinger Von Preussenthal
Joel F
JF
Habener
D000328:Adult; D017668:Age of Onset; D000368:Aged; D004247:DNA / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000235:genetics*; D005091:Exons / Q000235:genetics; D005260:Female; D051557:Hepatocyte Nuclear Factor 4; D006801:Humans; D007515:Islets of Langerhans / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense / Q000235:genetics / Q000502:physiology; D010375:Pedigree; D010641:Phenotype; D010679:Philippines; D010750:Phosphoproteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; C496592:HNF4A protein, human; D051557:Hepatocyte Nuclear Factor 4; D010750:Phosphoproteins; D014157:Transcription Factors; D004247:DNA