Detection of a New Variant of the Mitochondrial Glycerol-3-phosphate Dehydrogenase Gene in Spanish Type 2 DM Patients

• Published in: Biochemical and biophysical research communications Vol. 263; no. 2; pp. 439 - 445
• Main Authors: Gudayol, Mònica, Vidal-Taboada, Jose M., Usac, Elena F., Costa, Angels, Cristòbal, Pilar, dell‘Anna, Carmen, Oliva, Rafael, Gomis, Ramon
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 24.09.1999
• Subjects: Base Sequence; Binding Sites - genetics; Diabetes Mellitus, Type 2 - enzymology; Diabetes Mellitus, Type 2 - etiology; Diabetes Mellitus, Type 2 - genetics; European Continental Ancestry Group - genetics; Exons; Female; Flavin-Adenine Dinucleotide - metabolism; Flavoproteins - genetics; Genetic Testing; Genetic Variation; Glycerolphosphate Dehydrogenase - genetics; Humans; insulin secretion; intron mutation; Introns; Male; Meiosis; mGPDH; Mitochondria - enzymology; Mitochondria - genetics; Molecular Sequence Data; Pedigree; Polymorphism, Single-Stranded Conformational; Pseudogenes; retropseudogene; Reverse Transcriptase Polymerase Chain Reaction; Spain; Untranslated Regions; Spain; intron mutation; mGPDH; retropseudogene; insulin secretion
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.1999.1394

To evaluate if potential defects in the FAD-binding domain of the mitochondrial glycerol-3-phosphate dehydrogenase (mGPDH) gene could contribute to susceptibility to type 2 diabetes mellitus, we have screened 151 type 2 DM patients for mutations using PCR single-strand conformational polymorphism. Both a single substitution (T to A) at position 18 and a 6-base-pair deletion (TTTTAA) at position 26 of intron 3 have been detected in five type 2 DM patients and in one control subject. The evolution time of diabetes was longer in patients with these mutations than in patients without (24.2 ± 11.1 vs 12.6 ± 8.7 years, p < 0.02). These mutations generate a cryptic site that may have functional significance in the correct mechanism of the FAD-binding domain. In the process of PCR amplification of the mGPDH gene we also unexpectedly amplified the mGPDH retropseudogene. Subsequently, we decided to further characterize and completely sequence 2213 bp of this mGPDH retropseudogene. Our results suggest that two previously reported mGPDH pseudogene partial sequences may be identical copies of the mGPDH gene inserted in two different genomic locations and provide information about the alternative 5′- and 3′-untranslated regions. The data obtained are also important in order to avoid artifactual amplification of the mGPDH pseudogene in the process of screening for mGPDH mutations in diabetic patients.