Ankylosing spondylitis (AS) is a chronic rheumatic disease involving the spine and sacral hip.AS is the prototype disease of seronegative arthritis of the spine.Besides the violations of the spine,AS can also lead to violations of the peripheral joints,even the eyes,intestine,aortic root,and other tissues and organs.The pathogenesis of AS has remained unclear.AS,a genetic disease,is influenced by the genetic and environmental factors.Studies have suggested that HLA-B27 is the most critical genes to AS,and forming three kinds of hypotheses associated with HLA-B27.This paper reviews the molecular genetics and pathogenesis of AS.

Objective To investigate the epidemiological situation and the mode of inheritance of ankylosing spondylitis (AS).Methods The AS prevalence investigation was carried out from three different areas in Shandong Province to investigate the incidence of the 80 patients' family members of sick group and calculate the heritability of AS.Results After the investigation and calculation we found the incidence of primary relatives was 7.23％,the heritability was 85.94％,the incidence of secondary relatives was 0.94％ and the heritability was 57.4％,the incidence of thirdly relatives was 0.39％,the heritability is 36.2％,the average heritability among primary,secondary and thirdly was 68.47％ ± 1.64％.Separation ratio was 0.088 9.Conclusion AS is a polygenic disease,its average heritability was 68.47％ ± 1.64％ and separation ratio is 0.088 9.By this research,the incidence risk of AS patients' pedigree offspring can be assessed,then strengthen protective factors to reduce the incidence of the disease to provide the basis for eugenics.

Objective To study the relationship between the variation of the 20 exon of leptin receptor (LEPR) and lipid metabolism of the children with obesity. Methods Polymerase chain reaction-restricted fragments length polymorphism (PCR-RFLP) and polyacrylamide gel electrophoresis were used to analyze the variation of the 20 exon of the LEPR gene of the obesity group (120 obese children) and the control group (120 healthy children). Their serum triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), height, weight measured and the body mass index (BMI), fat percent (%fat) were calculated. Results 3 genotypes of the 20 exon of LEPR gene has been detected. Compared with the control group, the frequency of the gene variation at 3057 nucleotide G→A transversion is higher (P<0.05).The concentration of the serum TG, the level of BMI and %fat of the obese children with A/A genotype were higher than that with the G/G genotype (P<0.01),but the level of the serum HDL was lower (P<0.01).To the children with A/G genotype, only their TG level in serum are higher than that with the G/G genotype (P<0.05). Conclusion There is polymorphism at 20 exon LEPR gene in children with obesity, which may affect the lipid metabolism and the fat distribution. The obese children with A/A genotype should pay more attention to their diet to avoid some diseases followed obesity.