Apolipoprotein A1 and neuronal nitric oxide synthase gene polymorphisms and hormonerelated osteonecrosis of the femoral head

OBJECTIVE: This study was designed to investigate the influence of several polymorphisms in neuronal NOS genes and apolipoprotein AI on the hormone-related osteonecrosis of the femoral head (ONFH) risk. PATIENTS AND METHODS: Peripheral blood mononuclear cell (PBMCs) samples extracted from hormone-related ONFH patients and controls were used to amplify fragments of the apolipoprotein A1 and neuronal NOS exon 7 and intron 4 using specific PCR primers. The products were analyzed by DNA sequencing and mapped to find the genotype distributions. RESULTS: The proportions of G/G, G/T and T/T on NOS exon 7 in hormone-related ONFH patient group and control group were 68%, 27%, 5% and 81%, 16%, and 3% respectively. The proportions of G/T and T/T in the experimental group were significantly higher than those in the control group (p<0.05). The proportions of b/b, a/b and a/a on NOS intron 4 in hormone-related ONFH patient group and control group were 85%, 13%, 1% and 96%, 5% and 0% respectively. The proportion of a/b in the experimental group was much higher than in the control group. The distribution of A/A, G/A and G/G in the apolipoprotein gene in control and experimental groups were 19%, 33%, 71% and 42%, 20%, 38% respectively. In this case, the experimental group's A/A genotype was significantly higher than the control's genotype. CONCLUSIONS: In our study group, several polymorphisms of the neuronal NOS gene and apolipoprotein A1 genes were significantly associated with hormone-related ONFH. These results suggest that those gene polymorphisms might be involved in the occurrence and development of ONFH.