Serum vitamin D levels and gene polymorphisms (Fok1 and Apa1) in children with type I diabetes and healthy controls.

OBJECTIVE: To compare the pattern of Vitamin D receptor (VDR) polymorphisms (Apa I and Fok I) in Type I Diabetes mellitus (T1DM) as cases vs healthy population as control and to investigate the association of VDR polymorphism with vitamin D levels in cases and controls.

METHODS: The hypothesis of the study was "VDR gene polymorphisms (Fok 1 and Apa 1) and vitamin D levels are associated with the T1DM". The case-control study was carried out on 44 cases and 44 controls. Clinically diagnosed unrelated cases were recruited from the Diabetic Clinic of Jinnah Hospital, Lahore during Aug. 2012 to Jan 2013. Unrelated controls with normal glucose levels and no first-degree family history of T1DM were selected by convenient sampling. Vitamin D levels of both cases and controls were measured using Enzyme Linked Immunosorbant Assay (ELISA). Genotyping was performed by Restriction Fragment Length Polymorphism (RFLP)-PCR method and the data were analyzed statistically with IBM-SPSS 21.

RESULTS: Our results demonstrated suboptimal vitamin D levels in whole of our sample population, whether control or cases (p = 0.529). There was no statistically significant difference in 25-Hydroxyvitamin D3 levels between cases (11.351 ± 5.92) and controls (12.335 ± 6.64). VDR polymorphism was not associated with susceptibility to T1DM in our sample population. Similarly, no association between VDR polymorphism and vitamin D levels was observed i.e. FokI p=0.507 and p=0.543 and ApaI p=0.986 and p=0.307 for cases and controls respectively.

CONCLUSIONS: There is an overall deficiency of Vitamin D levels in cases and control subjects while SNPs association studies suggested that in our sample population there was no association of VDR gene polymorphisms Fok I and Apa I with TIDM.