Genotypes and polymorphisms of mutant CCR5-△32,CCR2-64I and SDF1-3'A HIV-1 resistance alleles in indigenous Han Chinese

Objective To evaluate the frequencies and polymorphisms of CCR5-△32,CCR2-641 and SDF1-3'A alleles conferring resistance to HIV-1 infection in Chinese population from Han ethnic origin.Methods This cohort was comprised of 1251 subjects(915 men and 336 women)aged 15 -80 years and none was HIV-1 positive.Genotyping of allelic CCR5-△32,CCR2-641 and SDF1-3' A variants was performed using PCR or PCR/RFLP assay,and further confirmed by direct DNA sequencing.Results Our finding shows that the△32 deletion mutation in the CCR5 gene does occur in this population and can be inherited in a Mendelian fashion in indigenous Han Chinese at a very low frequency of 0.00119(n= 1254).The frequencies of mutant CCR2-641 and SDF1-3'A alleles were 0.20023(n = 1251)and 0.2873(n = 893),in this population,which are higher than those found in American Caucasians.Furthermore the polymorphisms of CCR2-641 and SDF1-3' A alleles in the Han Chinese population were different from those in American Caucasians.Statistical analysis showed that the genotype distribution of CCR5-△32,CCR2-641 and SDF1-3' A alleles was in equilibrium according to the Hardy-Weinberg equation.Conclusion The CCR5-△32 mutation may not be a major resistant factor against HIV-1 infection in indigenous Han Chinese.The significance of higher frequencies of CCR2-641 and SDF1-3' A alleles (0.20023 and 0.2791)in the Han population remains to be clarified in HIV-1-positive carriers and AIDS patients.

Clinical applications of MARSALA for preimplantation genetic diagnosis of spinal muscular atrophy

Conventional PCR methods combined with linkage analysis based on short tandem repeats （STRs） or Karyomapping with single nucleotide polymorphism （SNP） arrays, have been applied to preimplantation genetic diagnosis （PGD） for spinal muscular atrophy （SMA）, an autosome recessive disorder. However, it has limitations in SMA diagnosis by Karyomapping, and these methods are unable to distinguish wild- type embryos with carriers effectively. Mutated allele revealed by sequencing with aneuploidy and linkage analyses （MARSALA） is a new method allowing embryo selection by a one-step next-generation sequencing （NGS） procedure, which has been applied in PGD for both autosome dominant and X-linked diseases in our group previously. In this study, we carried out PGD based on MARSALA for two carrier families with SMA affected children. As a result, one of the couples has given birth to a healthy baby free of mutations in SMA-causing gene. It is the first time that MARSALA was applied to PGD for SMA, and we can distinguish the embryos with heterozygous deletion （carriers） from the wild-type （normal） ones accurately through this NGS-based method. In addition, direct mutation detection allows us to identify the affected embryos （homozygous deletion）, which can be regarded as probands for linkage analysis, in case that the affected family member is absent, In the future, the NGS-based MARSALA method is expected to be used in PGD for all monogenetic disorders with known pathogenic gene mutation.