Familial aggregation of endometriosis in a large pedigree of rhesus macaques.
BACKGROUND
Endometriosis occurs in several non-human primate species that have menstrual cycles. This study investigated the prevalence and familial aggregation of endometriosis in one of those species, the rhesus macaque.


METHODS
Between 1978 and 2001, 142 animals with endometriosis were identified from necropsy and surgical records and through the use of magnetic resonance imaging (MRI) at the Wisconsin National Primate Research Center, Madison, USA. All cases were used to build one large multigenerational pedigree and nine nuclear families comprising 1602 females in total. By 2002, the pedigrees contained 124 cases diagnosed at necropsy; 17 at surgery and three at MRI. Female animals that had died aged > or = 10 years without endometriosis, had both ovaries until at least 1 year prior to death, and had a full necropsy, were considered unaffected.


RESULTS
The prevalence of endometriosis among necropsied animals aged > or = 10 years in the colony was 31.4% [95% confidence interval (CI) 26.9-35.9%]; prevalence increased with rising age and calendar age at death. Familial aggregation of endometriosis was strongly suggested by a significantly higher average kinship coefficient among affecteds compared with unaffecteds (P < 0.001) and a higher recurrence risk for full sibs (0.75; 95% CI 0.45-1.0) compared with maternal half sibs (0.26; 95% CI 0.10-0.41) and paternal half sibs (0.18; 95% CI 0.02-0.34). The segregation ratio among affected mothers (44.2%) was not significantly higher compared with unaffected mothers (36.6%).


CONCLUSIONS
The results support familial aggregation of endometriosis in the rhesus macaque, and indicate that this is a promising animal model for the investigation of mode of inheritance, the location of potential genetic susceptibility loci and the influence of environmental factors.
Zondervan
Krina T
KT
Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK. krina.zondervan@well.ox.ac.uk
Weeks
Daniel E
DE
Colman
Ricki
R
Cardon
Lon R
LR
Hadfield
Ruth
R
Schleffler
Joan
J
Trainor
Amanda Goudy
AG
Coe
Christopher L
CL
Kemnitz
Joseph W
JW
Kennedy
Stephen H
SH
D000367:Age Factors; D000818:Animals; D004195:Disease Models, Animal; D004715:Endometriosis / Q000453:epidemiology / Q000235:genetics / Q000662:veterinary*; D005260:Female; D020022:Genetic Predisposition to Disease; D008253:Macaca mulatta; D008279:Magnetic Resonance Imaging; D008992:Monkey Diseases / Q000235:genetics*; D010375:Pedigree