Variation of Mitochondrial DNA HV1 AND HV2 of the Vietnamese Population.

BACKGROUND: The sequence polymorphism of mitochondrial DNA (mtDNA) hypervariable segment 1 (HV1) and hypervariable segment 2 (HV2) is studied and applied to genetic diversity and human evolution assessment, forensic genetics, consanguinity determination, and mitochondrial disease diagnosis. METHODS: The study identified the variations of HV1 and HV2 of 517 unrelated Vietnamese individuals in Kinh, Muong, Cham, and Khmer ethnic. We performed sequencing of two hypervariable segments of mitochondrial DNA: HV1 and HV2. RESULTS: Fifty haplogroups were identified in which F1a haplogroup frequency was highest at 15.7%, followed by B5a (10.8%), M (8.9%), and M7b1 (7.7%). The most frequently encountered SNPs in this study were A263G (100%), A73G (99.6%), 315insC (96%), 309insC (56%), C16223T (41%), and T16189C (39%). The genetic diversity was calculated at 99.83%, and the probability of random match of two individuals sharing the same mtDNA haplotype was 0.37%. CONCLUSION: We have assessed the genetic polymorphism of mtDNA HV1 and HV2 of 517 Kinh, Muong, Cham, and Khmer ethnic samples. The result will help in better understanding of Vietnamese's mitochondrial genome diversity and aid in population as well as forensic science.

Rapid method for targeted prenatal diagnosis of Duchenne muscular dystrophy in Vietnam.

OBJECTIVE: Since there is no effective curative treatment for Duchenne muscular dystrophy (DMD), prevention mostly depends on genetic counseling and prenatal diagnosis. About two-thirds of the affected patients have large deletions or duplications, which can be detected by multiplex ligation-dependent amplification (MLPA). The remaining cases include small mutations, which cannot be easily identified by routine techniques. In such cases, linkage analysis may be a useful tool for prenatal diagnosis. Here we compared results obtained from linkage using short tandem repeats (STRs) with those by MLPA and sequencing analysis. MATERIALS AND METHODS: Eight Vietnamese pregnant women at risk of having a baby with DMD and requesting prenatal diagnosis were recruited in this study. MLPA and direct sequencing were applied to screen large rearrangements and point mutations in the dystrophin gene in the DMD probands and the fetal samples. STR linkage was also performed to analyze fetal mutation status. RESULTS: By MLPA and sequencing analysis, five DMD patients showed deletions of the dystrophin gene, and no deletions of exons were detected in seven amniotic fluid cell samples; one patient harbored the out-of-frame small deletion of exon 43, which was also found in the fetal sample of this family. STR analysis revealed the transmission of a mutant allele inside each family. CONCLUSION: Our results suggest that the combination of STR and MLPA could be a rapid, reliable, and affordable detection protocol for determination of the carrier's status and prenatal diagnosis of DMD in a developing country such as Vietnam.