A more recent study found that autism was 3–4 times more prevalent in children of Somali immigrant families to Sweden compared with the non-Somali population [120, 121]. The evidence that vitamin D supplementation affects rates of autism has been circumstantial at best. There is some data suggesting that vitamin D intake may positively influence measures of MI-503 purchase cognition, and that deficiency states result

in increased risk of lower verbal IQs, suboptimal outcomes in communication and social development, features observed in autism [122, 123]. Genetic contribution to autism risk is strong, based on family and twin studies, and there is some overlap of autism spectrum disorders with known genetic disorders [124, 125]. The list of candidate autism risk genes identified by GWAS is proliferating RXDX-106 cell line exponentially. Given the complex genetic architecture of

the disease, it has been suggested that gene-environment interactions must play a substantial role. On review of the GWAS identified genes, the PPP2R5C gene, a serine/threonine phosphatase implicated in the control of cell growth and division, appears to have a VDR-binding site. PPP2R5C has been implicated in retinogenesis and photoreceptor development [126], an interesting finding considering abnormal retinal function determined by electroretinography has been described in the disease (see Table 1) [127]. The role this susceptibility gene may play (if any) with the more broad and complex neurological phenotype is not known; however, it is clear that its regulation by vitamin D accentuates possible gene-environment interactions in a genetically susceptible individual. Parkinson’s disease

(PD) is a neurodegenerative disease characterized by the cardinal features of tremor, rigidity, akinesia, and postural instability. Pathologically, PD affects the central dopaminergic pathways with neuronal loss and α-synuclein aggregates in multiple brain regions [128, 129]. As previously discussed, a biological basis for a potential role of vitamin D in PD has been illustrated in various experimental those rodent models wherein vitamin D exerts a neuroprotective effect on mesencephalic dopaminergic neurones exposed to a variety of toxic conditions [46-49]. The relationship between hypovitaminosis D and risk of Parkinson’s disease has long been suggested from epidemiological studies. A season-of-birth effect has been observed in various PD cohorts, with an excess of births being reported in winter and early spring in England and Scotland [130]. A latitude effect may be operative in PD risk with a north-to-south latitude gradient (higher prevalence in the north) being observed in several studies [131-134].