Clinical features and treatment of the hip in multiple epiphyseal dysplasia in childhood.

Multiple epiphyseal dysplasia is a rare congenital osteochondrodysplasia disorder characterized by a delay in the appearance of the epiphyses; irregular, symmetric epiphyseal formation; mild short stature; and early-onset osteoarthritis. Peripheral weight-bearing and nonweight-bearing joints can be affected. Treatment of the hip deformity in multiple epiphyseal dysplasia is a challenge for orthopedic surgeons.We reviewed the clinical features and treatment options of hip joints affected by multiple epiphyseal dysplasia in 6 young patients (4 boys and 2 girls). Average patient age was 8.8 years (range, 5-14 years). The spectrum of hip joint deformity ranged from mild to severe. Surgical procedures included intertrochanteric extension osteotomy of the femur in 2 patients (4 hips), Staheli acetabular augmentation in 1 patient (2 hips), and trochanter arthroplasty associated with Dega osteotomy in 2 patients (4 hips). One patient did not undergo surgical treatment. All patients were followed up for an average 7.2 years. Joint function improved in the patients treated surgically. The coxa vara deformity was corrected satisfactorily, and the femoral head was covered completely by the acetabulum.Good mid-term outcomes were obtained for the treatment of severe hip deformity by using intertrochanteric extension osteotomy and trochanter arthroplasty. However, because of the inherent nature of this disorder, long-term follow-up of the patients is required.

Evaluation of the modified Albee arthroplasty for femoral head loss secondary to septic arthritis in young children: surgical technique.

BACKGROUND: Surgical treatment options for femoral head deficiency in infants secondary to septic arthritis of the hip are varied and associated with uncertain long-term outcomes. The modified Albee arthroplasty has been considered an acceptable procedure; however, the long-term outcomes of this procedure have not been reported, to our knowledge. We evaluated the long-term outcomes of the modified Albee arthroplasty in young patients with severe sequelae of septic arthritis of the hip. METHODS: We retrospectively studied twenty-one children (twenty-one hips) in whom Choi type-IVB sequelae of septic arthritis of the hip had been treated with a modified Albee arthroplasty and six patients with the same sequelae who had been managed with simple observation. The Trendelenburg sign, pain, the range of motion, hip function, the Harris hip score, and limb-length discrepancy were assessed clinically. Remodeling of the femoral head, hip stability, and arthritic changes in the hip were evaluated radiographically. RESULTS: The twenty-one patients with the modified Albee arthroplasty were followed for an average of 121.2 ± 38.6 months and had better outcomes, in terms of the Trendelenburg sign, the Harris hip score, pain, the hip range of motion, and limb-length discrepancy, than the six patients who underwent simple observation. Patients who were two years of age or younger at the time of the arthroplasty exhibited a significantly less severe limb-length discrepancy and less loss of motion than those who were older than two at the time of the surgery. Furthermore, limb-length discrepancy was positively correlated and the range of motion of the hip and the Harris hip scores were negatively correlated with the patient's age at the time of the surgery, suggesting that early surgery in patients with severe sequelae of septic arthritis of the hip is associated with a better clinical outcome. CONCLUSIONS: The modified Albee arthroplasty is a feasible and clinically useful procedure for the treatment of severe sequelae of septic arthritis of the hip, particularly in children who are two years of age or younger.

[Evaluation of mid-term follow-up after Salter innominate osteotomy in developmental dysplasia of the hip].

OBJECTIVES: To evaluate the mid-term outcome after Salter innominate osteotomy in developmental dysplasia of the hip (DDH), and to observe the developmental characteristics of the hip after operation and the relationships between the mid-term outcome and radiographic parameters as well as age at operation. METHODS: : Forty-four patients with 61 treated hips were selected. The patients were treated with Salter innominate osteotomy and followed-up for at least three years with intact serial radiographs. Radiographs taken before operation, 6 weeks, 1 year and 2 - 3 years after operation and in the latest follow-up were selected. Acetabular index (AI), Sharp acetabular angle (SAA) and center-edge angle of Wiberg (CEA) were measured and Severin classification was done according to radiographs taken in the latest follow-up. RESULTS: The average correction of AI was 14° postoperatively. The acetabulum remodels best at 2-3 years after operation when the average AI became very close to normal. In the latest follow-up the SAA was 41° which could be regarded as normal. Postoperative CEA was on average 23° which increased to 25° 2-3 years later. In the latest follow-up, the average CEA was 26°. The ratio of excellent and good outcomes (Severin I, II) was 84%, while the ratio of moderate and poor outcomes (Severin III, IV, V, VI) was 16%. Age at operation had a negative effect on outcomes. Although 70% patients operated after age 6 had satisfactory outcomes. The Severin I, II group showed no difference in AI from III, IV, V, VI group 6 weeks after operation, but the AI of the former obviously improved 2-3 years after operation while that of the latter deteriorated. Significant difference in SAA and the CEA could be observed in the latest follow-up. CONCLUSIONS: Salter innominate osteotomy focuses on normalizing the abnormal acetabular direction in DDH children as well as stimulating the remodeling of the acetabulum, which provides a satisfactory middle-term outcome. The acetabulum remodels rapidly during the first three years after operation when AI and CEA develops into normal. Interference should be adopted if these changes have not appeared in the first three years.

Evaluation of the modified Albee arthroplasty for femoral head loss secondary to septic arthritis in young children.

BACKGROUND: Surgical treatment options for femoral head deficiency in infants secondary to septic arthritis of the hip are varied and associated with uncertain long-term outcomes. The modified Albee arthroplasty has been considered an acceptable procedure; however, the long-term outcomes of this procedure have not been reported, to our knowledge. We evaluated the long-term outcomes of the modified Albee arthroplasty in young patients with severe sequelae of septic arthritis of the hip. METHODS: We retrospectively studied twenty-one children (twenty-one hips) in whom Choi type-IVB sequelae of septic arthritis of the hip had been treated with a modified Albee arthroplasty and six patients with the same sequelae who had been managed with simple observation. The Trendelenburg sign, pain, the range of motion, hip function, the Harris hip score, and limb-length discrepancy were assessed clinically. Remodeling of the femoral head, hip stability, and arthritic changes in the hip were evaluated radiographically. RESULTS: The twenty-one patients with the modified Albee arthroplasty were followed for an average of 121.2 +/- 38.6 months and had better outcomes, in terms of the Trendelenburg sign, the Harris hip score, pain, the hip range of motion, and limb-length discrepancy, than the six patients who underwent simple observation. Patients who were two years of age or younger at the time of the arthroplasty exhibited a significantly less severe limb-length discrepancy and less loss of motion than those who were older than two at the time of the surgery. Furthermore, limb-length discrepancy was positively correlated and the range of motion of the hip and the Harris hip scores were negatively correlated with the patient's age at the time of the surgery, suggesting that early surgery in patients with severe sequelae of septic arthritis of the hip is associated with a better clinical outcome. CONCLUSIONS: The modified Albee arthroplasty is a feasible and clinically useful procedure for the treatment of severe sequelae of septic arthritis of the hip, particularly in children who are two years of age or younger.

Pediatric synovial sarcoma of the sacrum: a case report.

We reported a rare synovial sarcoma arising within sacrum of a 12-year-old boy. A plain radiograph, magnetic resonance imaging performed before surgery, and the intraoperative findings showed that the tumor was S2 and below. Immunohistochemically, desmin and CD34 were negative. CK, CK7, CK1, CK3, CK8, CK19, Bcl-2, E-cadherin, ki-67, P53, SMA, CD99, CD56, S-100, vimentin, and epithelial membrane antigen were positive. Some were focal positively reactive to S-100, P53, and ki-67. The spindle cells were strongly positive for vimentin and CK3. The immunohistochemical findings confirmed its diagnosis of synovial sarcoma.

Thoracic rib solitary eosinophilic granuloma in a child.

Eosinophilic granuloma is characterized by single or multiple skeletal lesions occurring predominantly in children, adolescents, and young adults, it accounts for 70% of Langerhans cell histiocytosis. The common sites are the skull, mandible, ribs, spines, and long bones particularly the femur and the humerus. Thoracic rib involvement is rarely seen. It was often regarded as malignant soft tissue tumor. We report an unusual case of eosinophilic granuloma in a female child presented with a solitary lesion at the thoracic rib.

[Association study between mutations of transcription regulator sequences of COL1A1 gene and idiopathic con-genital talipes equinovarus].

RT-PCR was used to detect the expressions of COL1A1 mRNA in 20 patients with idiopathic congenital talipes equinovarus (ICTEV). The primers were designed by Primer 5 according to sequences of -1 031 bp~ +30 bp and the first intron of COL1A1. PCR-DGGE was used to screen the mutations in COL1A1 gene. Expression of COL1A1 on mRNA levels showed significantly higher in patients with ICTEV than in normal persons (t=12.680, P < 0.05). By DNA sequencing, a -161(T--> C) heterozygous mutation and a+ 274(C-->G) homozygous mutation were detected, and both were new identified mutations. These results indicated that the mutations in transcription regulator sequences of COL1A1 could cause ICTEV.

[Proteomic analysis of the ankle joint bone, ankle joint tissue and spinal cord of clubfoot-like deformity in rat fetuses].

OBJECTIVE: To explore the etiology of idiopathic talipes equinovarus (ITEV) in all-trans retinoic acid (ATRA) induced clubfoot-like deformity in rat fetuses with two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS). METHODS: Clubfoot-like deformity model in rat fetuses was induced with ATRA (135 mg/kg) in gestation day (GD10) pregnant Wistar rats. 2-DE was applied to separate the total proteins of ankle joint tissue, ankle joint bone and spinal cord of the animal models. The Coomassie Brilliant Blue staining gels were analyzed by 2-DE software PDQuest 7.1.0. Selected differential protein spots were identified with peptide mass fingerprinting based on matrix-assisted laser adsorption/ionization time-of-flight mass spectrometry and database searching. xiap, tnnt1 and col2 alpha 1, three genes of the differential proteins, were identified furthermore. Apoptosis study was made in terminal deoxynucleotidyl transferase nick end labeling. RESULTS: There were many differential expressed proteins in the clubfoot-like deformity model. Out of the differentially expressed proteins,16 protein spots were identified to be differentially expressed in the clubfoot-like deformity model with MS. Three of the 16 protein spots, xiap, tnnt1 and col2 alpha 1 were confirmed to be significantly down-regulated by the RT-PCR, and Xiap was further confirmed to be significantly down-regulated with immunohistochemistry. Another randomly selected gene, ngfr, did not express differently in ATRA-induced clubfoot-like deformity in rat fetuses. The rates of the apoptosis in the spinal, bone of the clubfoot-like deformity fetuses was 5.4 and 10 times of those of the normal fetuses respectively. CONCLUSION: The results suggest that there are certain differently expressed proteins in ankle joint tissue, ankle joint bone and spinal cord of the ATRA-induced clubfoot-like deformity in rat fetuses, and Xiap, sTnT, and Col2 alpha 1 show a significant correlation with ITEV. Ngfr is not correlation with ITEV. Apoptosis plays a key role in the development of ITEV and related to the decreased expression of the Xiap.

[Association and mutation analysis of GLI3 gene in idiopathic congenital talipes equinovarus].

OBJECTIVE: To explore the association and mutation of GLI3 gene in idiopathic congenital talipes equinovarus(ICTEV). METHODS: (1) Genotype of 2 single nucleotide polymorphism (SNP) in 84 idiopathic congenital talipes equinovarus nuclear pedigree were analyzed by restriction fragment length polymorphism. Association analysis was directed between single SNP locus and ICTEV through ETDT software, respectively.(2) Mutation sites in exon 9,10,11,12 of GLI3 gene were detected in 103 patients with ICTEV by denaturing gradient gel electrophoresis technique. RESULTS: rs929387ls located in exon 14 of GLI3 gene have transmission disequilibrium in 84 nuclear pedigrees (P<0.05), and rs846266 located in exon 4 have no transmission disequilibrium (P>0.05). A synonymous mutation in exon 9 was detected in one patient and his mother. CONCLUSION: There is an association between GLI3 gene and ICTEV, and exons 9,10,11,12 are not its mutation hot spots.

Renal expression of epidermal growth factor and transforming growth factor-beta1 in children with congenital hydronephrosis.

OBJECTIVES: To study the potential role of pelviureteral junction obstruction (PUJO) in causing progressive renal damage in children through the renal expression of epidermal growth factor (EGF) and transforming growth factor-beta1 (TGF-beta1). METHODS: The expression of EGF and TGF-beta1 was evaluated in the renal tissues of 25 children with congenital hydronephrosis by immunohistochemistry, in situ hybridization, and reverse transcriptase polymerase chain reaction techniques. RESULTS: Children with PUJO had a significant increase in TGF-beta1 and a marked reduction in EGF expression compared with controls. The TGF-beta1/glyceraldehyde phosphate dehydrogenase ratio in the hydronephrotic kidney and normal kidney was 0.53 +/- 0.13 and 0.24 +/- 0.10 respectively, and the difference was significant (P = 0.000). The EGF/glyceraldehyde phosphate dehydrogenase ratio in the hydronephrotic kidney and normal kidney was 0.15 +/- 0.06 and 0.55 +/- 0.13, respectively, and the difference was also significant (P = 0.0001). Positive correlations were found between the TGF-beta1 gene and the drainage clearance half-time (r = 0.47; P = 0.018), TGF-beta1 protein and drainage clearance half-time (r = 0.44; P = 0.028), TGF-beta1 gene and histologic grade (r = 0.53; P = 0.006), and TGF-beta1 protein and histologic grade (r = 0.76; P = 0.000). Negative correlations were found between the EGF gene and drainage clearance half-time (r = -0.59; P = 0.002), EGF protein and drainage clearance half-time (r = -0.61; P = 0.001), EGF gene and histologic grade (r = -0.58; P = 0.003), and EGF protein and histologic grade (r = -0.47; P = 0.019). CONCLUSIONS: TGF-beta1 expression was increased and EGF expression was decreased in the renal tissue after clinical PUJO. The alterations of TGF-beta1 and EGF may play a potential role in the pathogenesis of renal damage in PUJO.

[Analysis of association between 5' HOXD gene and idiopathic congenital talipes equinovarus].

OBJECTIVE: Four single nucleotide polymorphisms (SNP) in HOXD10, HOXD12 and HOXD13 genes were chosen to investigate SNP and haplotypes distribution in idiopathic congenital talipes equinovarus nuclear pedigrees. METHODS: Genotypes of 4 SNPs in 84 idiopathic congenital talipes equinovarus nuclear pedigrees were analyzed by restriction fragment length polymorphism and DNA sequencing. Analysis of association between SNP locus and idiopathic congenital talipes equinovarus was performed using ETDT software. Haplotypes and their frequencies in 84 nuclear pedigrees were established and analyzed by TRANSMIT software. RESULTS: rs847151 polymorphism was not detected; the rs847154 located in 5' flanking sequence of HOXD12 gene and the rs13392701 located in exon 1 of HOXD13 gene were noted to have transmission disequilibrium in 84 nuclear pedigrees (P < 0.05). CONCLUSION: rs847154 located in 5' flanking sequence of HOXD12 gene and rs13392701 located in exon 1 of HOXD13 gene are associated with idiopathic congenital talipes equinovarus; HOXD12 andHOXD13 are important susceptible genes of idiopathic congenital talipes equinovarus.

[Association analysis on the polymorphisms of PCOL2 and Sp1 binding sites of COL1A1 gene and the congenital dislocation of the hip in Chinese population].

OBJECTIVE: To investigate the polymorphism distribution of the PCOL2 and Sp1 binding sites of the collagen type I alpha 1(COL1A1) gene in Chinese population and explore their relationship with congenital dislocation of the hip (CDH). METHODS: The PCOL2 polymorphism (-1997 G/T) in COL1A1 promoter and the Sp1 polymorphism (1546 G/T) in intron 1 were genotyped in 243 members from 81 CDH nuclear family trios by the technique of polymerase chain reaction-restriction fragment length polymorphism, and then transmission disequilibrium test was used to analyze the data of genotypes. RESULTS: No statistically significant association was observed between CDH and PCOL2 polymorphism. Significant differences of genotype and allele frequency distributions were detected between the Chinese population and the Caucasian population in Spain, and between the Chinese population and the Caucasian population in America. The allele at the Sp1 site that has been found to be polymorphic in other populations was not found in Chinese. CONCLUSION: There exists racial difference in the distribution of the PCOL2 and Sp1 polymorphisms of COL1A1 gene. The results suggest that the PCOL2 and Sp1 polymorphisms may not be the major susceptibility gene of CDH in Chinese population.

[The primary observation of congenital clubfoot].

OBJECTIVE: To explore the possible correlations between clinical and experimental pathological changes of congenital clubfoot and the pathodynamic developmental procedure. METHODS: Eighty-three female Wistar rats were administered with retinoic acid on the 10th day after pregnancy. And from February 2001 to February 2004, 48 patients were analyzed with electropysiological examination. RESULTS: There was clubfoot-like deformity in 53.7% of the experimental fetuses. Persistence of the embryonic position of the talus and tibia in fetuses was observed. Poor overlapping between talus and calcaneus was seen. Cell apoptosis at the anterior corner of spinal cord were seen. Of all the patients, 68.3% were abnormal with electropysiological examination. The pathological sites were frequently localized in lumbarsacral region. CONCLUSION: Congenital clubfoot is correlated closely with defects of neural tube and spinal cord.

[Effect of the regulation of IGFs system components in retinoic acid-induced congenital clubfoot].

The fetal rat models with congenital clubfoot were constructed by treating 24 Wistar rats with all trans retinoic acid (ATRA). The MC-3T3-E1 cells were cultured with ATRA, 17 beta-estrogen (E2) or combinations of the two chemicals. The flow cytometer was used to determine the cell proliferation. The insulin-like growth factor-II (IGF-II ) and IGF conjugated protein-6 (IGFBP-6) mRNA level in rat calvaria bone tissue and MC-3T3-E1 cells were detected by northern blotting analysis and reverse transcription polymerase chain reaction. The congenital clubfoot of fetal rat was induced by ATRA in concentration of 100 approximately 140 mg/kg with dosage-dependence effect. The expression of IGF-II mRNA and cell proliferation were enhanced by E2(1 x 10(-6) mol/L) in rat calvaria bone tissue and MC-3T3-E1 cells, whereas the IGFBP-6 mRNA was increased. ATRA(1 x 10(-6) mol/L), however, inhibited the effect of E2 on regulation of IGF- II gene and IGFBP-6 gene as well as MC-3T3-E1 cell proliferation. These findings provide the evidence that ATRA can induce congenital skeleton malformation and congenital clubfoot in pregnant Wistar rats. IGF-II and IGFBP-6 are important regulative factors for skeleton development and osteoblast proliferation in rat.

[Changes of neural electrophysiology properties of cauda equina in experimental lumbar spinal canal stenosis under dynamic burden].

OBJECTIVE: To study the changes of neural electrophysiology properties of cauda equina under double level compression and dynamic burdens, and to clarify the mechanisms of intermittent neurogenic claudication. METHODS: Thirty SD rats were divided into 5 groups (6 in each group). The laminectomy of L5 was performed in control group. In the experimental groups, the silicon sheets were inserted into the spinal canal of L4 and L6 to cause double level compression of cauda equina by 30%. Two hours after onset of compression, no dynamic burden was introduced in experimental group 1. Only high frequency stimulation(HFS) was introduced for 6 minutes in experimental group 2. Both HFS and additional increased compression were introduced for 6 minutes in experimental group 3. While only additional increased compression was introduced for 6 minutes in experimental group 4. After 6 minutes of dynamic burdens, all were returned to the status of static compression for another 30 minutes and then electrical examination was made. RESULTS: After 2 hours of compression, motor and sensory nerve conduction velocity (NCV) of all the four experimental groups decreased significantly (P < 0.05), but there was no significant difference between them. There was no significant change in the control group. There was no significant change of NCV in experimental group 1 during the last 30 minutes of experiment. NCV in the other three experimental groups decreased after introduction of dynamic burdens, especially in the experimental group 3. CONCLUSION: The above results showed that NCV of cauda equina decreased significantly under dynamic burdens during static compression. Two kinds of dynamic burdens introduced at the same time can cause more profound change than a single one.

[Antiestrogenic effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the gene expression of insulin-like growth factors family in osteoblast cells].

OBJECTIVE: To investigate the antiestrogenic effect of environment teratogen on the gene expression of insulin-like growth factors (IGFs) family in osteoblast cells during rat skeleton development. METHODS: The fetal rat models with congenital skeleton malformation were constructed by treating 20 female Wistar rats with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on pregnant day 10. The MC-3T3-E1 cells were cultured with estrogen, TCDD, or a combination of the two chemicals for 24 hours. The IGF-II and IGFBP-6 mRNA levels in rat calvaria bone tissue and MC-3T3-E1 cells were detected by reverse transcription-polymerase chain reaction. Flow cytometer was used to determine the cell proliferation. RESULTS: TCDD at the concentration of 5-15 microg/kg induced developmental skeleton defect of fetal rat, and the effect was dose-dependent. The expression of IGF-II mRNA gene was enhanced by estrogen in rat calvaria bone tissue and MC-3T3-E1 cells, whereas IGFBP-6 mRNA was decreased. Estrogen increased the cell proliferation in MC-3T3-E1 cells. TCDD, however, inhibited the effect of estrogen on regulation of IGF-II gene and IGFBP-6 gene as well as MC-3T3-E1 cell proliferation. CONCLUSION: These findings provide the evidence that TCDD can induce congenital fetal skeleton malformation under the condition of high estrogen level in pregnant Wistar rats. TCDD has antiestrogenic effect and hence exerts negative influence on the osteoblast cells through target IGF-II and IGFBP-6 of IGFs family.

The expression of epidermal growth factor and transforming growth factor-beta1 in the stenotic tissue of congenital pelvi-ureteric junction obstruction in children.

PURPOSE: The aim of this study was to test the hypothesis that expression of epidermal growth factor (EGF) and transforming growth factor-beta 1 (TGF-beta 1) may be altered in stenotic tissue of patients with congenital hydronephrosis caused by pelviureteric junction (PUJ) obstruction and to evaluate the role of these 2 growth factors. METHODS: The expression of EGF and TGF-beta 1 was evaluated in tissue specimens in 25 children with PUJ obstruction and 15 controls with normal PUJs by immunohistochemistry, in situ hybridization, and reverse transcriptase polymerase chain reaction (RT-PCR) techniques. All the signals of mRNA products were normalized to the mRNA levels of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) a housekeeping gene, as a ratio. RESULTS: On RT-PCR study, the amount of TGF-beta 1 mRNA in stenotic tissue was higher than in controls, in addition, EGF gene expression in the obstructed junction was significantly lower than in normal junctions. The TGF-beta 1 to GAPDH ratio was 0.57 +/- 0.26 and 0.36 +/- 0.19 in the stenotic tissue and the normal ureter, respectively (P =.012). The EGF to GAPDH ratio was 0.17 +/- 0.08 and 0.37 +/- 0.14 in the stenotic tissue and the normal ureter, respectively (P =.0001). Furthermore, the positive correlations were found between TGF-beta1 gene and protein expression (r = 0.601; P =.001), TGF-beta 1 gene and drainage clearance half-time (T1/2) (r = 0.474; P =.017), TGF-beta 1 protein expression, and T1/2 (r = 0.516; P =.008). A negative correlation was found between EGF gene and T1/2 (r = -0.448; P =.025). On immunolabeling and in situ hybridization labeling, the expression of TGF-beta 1 protein was strongly positive and confined to the muscle cells, spindle cells, and collagen fibers in the stenotic tissue; the expression of TGF-beta 1 mRNA was moderately positive and mainly distributed in the collagen of the stenotic segment, both the expression of EGF protein and mRNA were negative in the normal ureter. CONCLUSIONS: There were increased TGF-beta 1 mRNA expression and decreased EGF mRNA expression in the stenotic tissue after clinical ureteropelvic junction obstruction. The alteration of EGF and TGF-beta 1 expression may be involved in the pathogenesis of congenital hydronephrosis.

[Transmission disequilibrium test for congenital dislocation of the hip and HOXB9 gene or COL1AI gene].

OBJECTIVE: To detect the correlation between the congenital dislocation of the hip (CDH) and HOXB9 gene or COL1AI gene. METHODS: A microsatellite DNA marker D17S1820 was chosen in the region of chromosome 17q21 where exists the HOXB9 gene which regulates the embryonic limb development and exists the COL1AI gene. The genotypes of 303 members in 101 CDH nuclear family trios were analyzed by the techniques of polymerase chain reaction(PCR) and denaturing polyacrylamide gel electrophoresis. Then transmission disequilibrium test (TDT) was used to test the data of genotypes. RESULTS: There exist 12 alleles at this polymorphic locus. Transmission disequilibrium was found between CDH and the fourth allele of D17S1820 (chi-square=6.025,P=0.014). CONCLUSION: CDH is associated with the region of chromosome 17q21. HOXB9 gene and/or COL1AI gene may be susceptibility genes of CDH.