Gene mapping of developmental dysplasia of the hip in chromosome 17q21 region / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To map the susceptibility gene of developmental dysplasia of the hip(DDH) in chromosome 17q21 region.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>The susceptibility gene for DDH is narrowed to an 11.7 cM region of 17q21.31-17q22, between STR loci D17S855 and D17S790.</p>

Distribution and expression of TGF-ß2 in the capsule of children with developmental dysplasia of the hip / 中国当代儿科杂志

<p><b>OBJECTIVE</b>This study examined the distribution and expression of transforming growth factor-ß₂ (TGF-ß₂) in the hip capsule of children with developmental dysplasia (dislocation) of the hip (DDH) and non-DDH children in order to investigate the roles of TGF-ß₂ in hip joint laxity.</p><p><b>METHODS</b>Eight children with DDH and eight age- and gender-matched non-DDH children (control group) were enrolled. The immunohistochemical technique (S-P method) was used to examine the distribution and content of TGF-ß₂ in the hip capsule. Semiquantitative RT-PCR method was used to detect mRNA expression of TGF-ß₂ in the hip capsule. The quantitative analysis of TGF-ß₂ was performed by professional image software.</p><p><b>RESULTS</b>A high expression of TGF-ß₂ was observed in the synovial layer with fibroblast regularly arranged parallel to the joint surface. There was decreased expression of TGF-ß₂ in the fibrous layer of the capsule. The percentage of positive fibroblasts and the gray-scale density in the fibrous layer in the DDH group were significantly lower than those in the control group (P < 0.01). TGF-ß₂ mRNA expression in the DDH group decreased compared with that in the control group (P < 0.05).</p><p><b>CONCLUSIONS</b>The decreased TGF-ß₂ in distribution, content and mRNA expression in the hip capsule might contribute to hip joint laxity in children with DDH.</p>

Expression of COL1a1 and COL3a1 in the capsule of children with developmental dislocation of the hip / 中国当代儿科杂志

<p><b>OBJECTIVE</b>The etiology of developmental dislocation of the hip (DDH) remains uncertain, but some research has shown that this disorder is closely related to hip joint laxity. This study examined the expression of collagens type I and III mRNA and protein in the hip capsule of children with DDH in order to investigate the roles of collagens type I and III in hip joint laxity.</p><p><b>METHODS</b>Nine children with DDH and nine age and gender-matched normal children (control group) were enrolled. Semiquantitative RT-PCR method was used to detect mRNA expression of COL1a1 and COL3a1 in the hip capsule. Western-Blot method was used to detect protein expression of COL1a1 and COL3a1 in the hip capsule. The quantitative analysis of the COL1a1 and COL3a1 was performed by professional image software and the results were analyzed with standard statistical methods.</p><p><b>RESULTS</b>mRNA and protein expression of COL1a1 in the DDH group was significantly lower than that in the control group (P<0.01). Compared with the control group, COL1a3 mRNA expression in the DDH group decreased significantly (P<0.01), but COL1a3 protein expression was not significantly different.</p><p><b>CONCLUSIONS</b>The decreased collagen I mRNA and protein expression in the hip capsule might contribute to hip joint laxity in children with DDH. Collagen type III may not be associated with hip joint laxity in DDH.</p>