Association of cryptorchidism with a specific haplotype of the estrogen receptor alpha gene: implication for the susceptibility to estrogenic environmental endocrine disruptors.
BACKGROUND
The prevalence of cryptorchidism (CO) has increased during the past few decades in several countries, and this event has primarily been ascribed to the estrogenic effects of environmental endocrine disruptors (EEDs). Little is known, however, about the role of genetic susceptibility to EEDs in this phenomenon.


OBJECTIVE
The objective of this study was to determine whether CO is associated with a specific haplotype of the gene for estrogen receptor alpha (ESR1) that mediates the estrogenic effects of EEDs.


METHODS
This was a case-control study.


METHODS
The study was performed at the National Research Institute and University Hospitals.


METHODS
Sixty-three cryptorchid males, aged 1-13 yr, and 47 control males, aged 4-12 yr, were studied.


METHODS
After genotyping 15 single nucleotide polymorphisms widely distributed in the greater than 300-kb genomic sequences of ESR1, haplotype analysis was performed.


METHODS
Identification of a specific ESR1 haplotype associated with CO was the main outcome measure.


RESULTS
A haplotype block was identified for an approximately 50-kb region encompassing single nucleotide polymorphisms 10-14 in the 3' region of ESR1 in both groups. The frequency of the estimated AGATA haplotype within the block was higher in the patients than in the control males (34.0% vs. 21.3%; P = 0.037), and the association of this haplotype with CO phenotype was significant in a recessive mode (P = 0.0060). The homozygosity for this haplotype was identified only in the patients, and the frequency of the homozygotes was significantly different between the two groups (10 of 63 vs. zero of 47; P = 0.0042).


CONCLUSIONS
The association of CO with homozygosity for the specific ESR1 haplotype suggests the relevance of genetic susceptibility to EEDs in the development of CO.
Yoshida
Rie
R
Department of Endocrinology and Metabolism, National Research Institute for Child Health and Development, 2-10-1 Ohkura, Setagaya, Tokyo 157-8535, Japan.
Fukami
Maki
M
Sasagawa
Isoji
I
Hasegawa
Tomonobu
T
Kamatani
Naoyuki
N
Ogata
Tsutomu
T
D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003456:Cryptorchidism / Q000209:etiology / Q000235:genetics*; D004781:Environmental Exposure; D047628:Estrogen Receptor alpha / Q000235:genetics*; D004967:Estrogens; D020022:Genetic Predisposition to Disease; D006239:Haplotypes; D006801:Humans; D007223:Infant; D015810:Linkage Disequilibrium; D008297:Male; D020641:Polymorphism, Single Nucleotide
D047628:Estrogen Receptor alpha; D004967:Estrogens