Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.
Increased Male Fetal Loss and Fewer Male Siblings in a Cohort of Systemic Lupus Erythematosus Families.
Aggarwal1, Rachna, Scofield2, Robert H.
A sex bias has been found absent in sibships of non-female predominant diseases like diabetes. We undertook this study to enhance our understanding of sex ratios in live sibships and lost fetuses in a large cohort of Systemic lupus erythematosus (SLE).
Families were collected through the Lupus Family Registry and Repository. All patients met atleast four of the 1982 ACR classification criteria for SLE. All families had atleast one member with SLE. Collective sibling gender data were obtained for the SLE cohort studied. Spontaneous miscarriage and abortion information was assessed, when self-reported, on a standard questionnaire filled by the patient. Male to female sex ratios were calculated.
Collectively, 282 SLE affected male patients had 314 male siblings and 415 female siblings. The 2296 SLE affected female patients had 3113 male siblings and 3772 female siblings. Thus the ratio of male to female siblings= (314+3113) / (3772+415) = 0.82. SLE affected females reported 36 events of male fetal loss and 20 events of female fetal loss. Thus, ratio of male to female fetal loss was found to be 1.8:1.
There is a trival explanation for too few male siblings in this cohort. Sibships with lots of girls are more likely to have SLE because of the excess girls with SLE and, therefore are more likely to be included in the study. So, to correct for the ascertainment bias, we left out the SLE patients. Even when doing this, the male/female ratio is 0.8 and live births and fetal loss is nearly twice more common in males. The most parsimonious and perhaps the only explanation is a gene on X where a mutation or allele is lethal for males in utero and gives girls risk for SLE as we have discussed. This means this gene should be on the maternal X chromosome of patients in families where the sibship containing the SLE patient has excess girls and/or there are reports of male fetal loss.
To cite this abstract, please use the following information:
Aggarwal, Rachna, Scofield, Robert H.; Increased Male Fetal Loss and Fewer Male Siblings in a Cohort of Systemic Lupus Erythematosus Families. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1193