The link of C4B null allele to autism and to a family history of autoimmunity in Egyptian autistic children

The reason behind the initiation of autoimmunity, which may have a role in autism, is not well understood. There is an association between some autoimmune disorders and complement (C) 4B null allele. We aimed to study the association between C4B null allele and autism. In addition, we are the first to investigate the association between this allele and a family history of autoimmune diseases in autistic children. Therefore, we examined the frequency of C4B null allele, by quantitative real-time PCR, in 80 autistic patients and 80 healthy matched-children. The frequency of C4B null allele was significantly higher in autistic patients (37.5%) than healthy controls (8.75%), P<0.001. The frequency of autoimmune diseases in families of autistic children (40%) was significantly higher than healthy children (10%), P<0.001. In addition, a family history of autoimmunity had a significant risk for association with autism (odds ratio = 6, 95%, CI = 2.5-14.1). C4B null allele had a significant risk for association with autism (odds ratio = 6.26, 95% CI = 2.55-15.36) and with a family history of autoimmunity (odds ratio = 21, 95% CI = 6.5-67.8). Conclusions: the link of C4B null allele to autism and to a family history of autoimmunity may indicate its possible contributing role to autoimmunity in autism. (C) 2010 Elsevier B.V. All rights reserved.