ABSTRACT
OBJECTIVE: To map the susceptibility gene of developmental dysplasia of the hip(DDH) in chromosome 17q21 region. METHODS: According to the number of alleles (≥ 5), heterozygosity (≥ 0.70) and polymorphic information content (PIC≥ 0.5), 11 STR markers in the 17q21 region were chosen for transmission disequilibrium test (TDT). STR markers were amplified by PCR and genotypes were analyzed by capillary electrophoresis in 103 trio families. TDT was used to locate the susceptibility gene in 17q21 region. RESULTS: Because of a low genetic polymorphism, D17S810 and D17S931 loci were removed from the TDT. Transmission disequilibrium was detected at D17S855, D17S858, D17S806, D17S1877, D17S941, D17S752 and D17S790, which overlapped 11.7 cM in 17q21. However, no transmission disequilibrium was found at D17S1787 and D17S787. Thus, the susceptibility gene for DDH was located in the chromosome region between D17S855 and D17S790. CONCLUSION: The susceptibility gene for DDH is narrowed to an 11.7 cM region of 17q21.31-17q22, between STR loci D17S855 and D17S790.
Subject(s)
Chromosome Mapping/methods , Chromosomes, Human, Pair 17/genetics , Hip Dislocation, Congenital/genetics , Child , Child, Preschool , Cloning, Molecular , Female , Genetic Predisposition to Disease/genetics , Humans , Infant , Linkage Disequilibrium/genetics , Male , Microsatellite Repeats/genetics , Polymorphism, Genetic/geneticsABSTRACT
OBJECTIVE: To establish a new method of SNP typing. METHODS: Based on the principle of allele specific PCR and capillary electrophoresis technique, 11 diallelic SNP loci were selected and two forward primers with different length were designed for each SNP, with their 3' ends matched to the two alleles, respectively. An artificially mismatched base was also introduced into the third or fourth base in the 3' end area of the two forward primers in order to enhance the specificity of amplification. A common reverse primer was designed 100-300 bp away from the forward primers, and labeled with fluorescence. The PCR products were separated and analyzed by ABI Prism 310 Genetic Analyzer after all of the 11 SNPs were multiply amplified. RESULTS: A single product peak was observed while the SNP was homozygous, and two product peaks with different height were observed while the SNP was heterozygous. The length of PCR products was different with the different SNPs. According to the length of the products and the number of the product peaks, the genotypes of the 11 SNPs can simultaneously be analyzed, and the results were in accordance with the direct sequencing. CONCLUSION: Fragment length discrepant allele specific fluorescence labeled multi-PCR (FLDASFLM-PCR) is a simple, rapid and efficient new method for SNP typing.
