Sex-related bias and exclusion mapping of the nonrecombinant portion of chromosome Y in human type 1 diabetes in the isolated founder population of Sardinia.
A male excess in Sardinian type 1 diabetic cases has previously been reported and was largely restricted to those patients carrying the HLA-DR3/nonDR4 genotype. In the present study, we have measured the male- to-female (M:F) ratio in a sample set of 542 newly collected, early-onset type 1 diabetic Sardinian patients. This data not only confirm the excess of male type 1 diabetic patients overall (M:F ratio = 1.3, P = 3.9 x 10(-3)) but also that the bias in male incidence is largely confined to patients with the DR3/nonDR4 genotype (M:F ratio = 1.6, P = 2.0 x 10(-4)). These sex effects could be due to a role for allelic variation of the Y chromosome in the susceptibility to type 1 diabetes, but to date this chromosome has not been evaluated in type 1 diabetes. We, therefore, established the frequencies of the various chromosome Y lineages and haplotypes in 325 Sardinian male patients, which included 180 cases with the DR3/nonDR4 genotype, and 366 Sardinian male control subjects. Our results do not support a significant involvement of the Y chromosome in DR3/nonDR4 type 1 diabetic cases nor in early-onset type 1 diabetes as a whole. Other explanations, such as X chromosome-linked inheritance, are thus required for the male bias in incidence in type 1 diabetes in Sardinia.
Contu
Daniela
D
Dipartimento di Scienze Biomediche e Biotecnologie, Università di Cagliari, Ospedale Microcitemico, Via Jenner, Cagliari 09121, Italy.
Morelli
Laura
L
Zavattari
Patrizia
P
Lampis
Rosanna
R
Angius
Efisio
E
Frongia
Paola
P
Murru
Daniela
D
Maioli
Mario
M
Francalacci
Paolo
P
Todd
John A
JA
Cucca
Francesco
F
D002648:Child; D002675:Child, Preschool; D002874:Chromosome Mapping; D035061:Control Groups; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology* / Q000235:genetics*; D005260:Female; D018703:Founder Effect; D005787:Gene Frequency; D005838:Genotype; D015803:HLA-DR3 Antigen / Q000235:genetics; D015804:HLA-DR4 Antigen / Q000235:genetics; D006239:Haplotypes; D006801:Humans; D015994:Incidence; D007558:Italy; D008297:Male; D017678:Sex Distribution; D014998:Y Chromosome / Q000235:genetics*
D015803:HLA-DR3 Antigen; D015804:HLA-DR4 Antigen