When asked about the possible causes of MNS disorders, more than half of the PHC workers reported genetic predisposition and neurochemical imbalance as risk factors for MNS disorders, which is similar to a study of PHC workers in Nepal [ 23].
As a further clue of the importance of genomic variations in NB, Oldridge et al. have recently reported genomic predisposition to NB mediated by a SNP in a super-enhancer region of the LMO1 gene.
Recently, reduced natural regulatory T (Tregs) cells in children with TS or OCD or both were reported, indicating a predisposition for overriding autoimmune responses [ 31].
The pattern is consistent with the familial predisposition reported for pancreatic cancer and with the array of tumours associated with hereditary non-polyposis colon cancer.
Nevertheless, a proportion of melanoma families linked to the 9p21 locus do not harbour germline mutations of INK4a-ARF, and three large deletions have been reported in hereditary predisposition to melanoma and nervous system tumours, two involving both p16 INK4andnd p14 ARF (Bahuau et al, 1998), and one restricted to exon 1 β of p14 ARF (Randerson-Moor et al, 2001).
Although the aetiology of PPFE is considered idiopathic in most cases, an association with a wide range of factors has been reported such as genetic predisposition; recurrent lower respiratory tract infections; underlying diseases or conditions such as collagen vascular diseases, bone-marrow transplantation or lung transplant patients suffering from restrictive allograft syndrome [5, 6, 7, 8].
Several studies have reported a strong familial predisposition for disc degeneration and herniation [ 97- 99].
Though rare, familial predisposition is reported from several countries and different ethnic groups [ 3- 9].
By now, many ATM mutations have been reported to increase cancer predisposition, including truncation and missense mutations [ 201, 203– 206].
Poly(ADP-ribose) polymerase activity can be higher in cancer than in adjacent normal tissue, but cancer predisposition is reported to be greater in individuals with a single-nucleotide polymorphism (SNP) V762A (T2444C) in the catalytic domain that reduces PARP-1 activity.
