Figure 1From: C4B null alleles are not associated with genetic polymorphisms in the adjacent gene CYP21A2in autism Three common arrangements of the RCCX module. Monomodular, bimodular, and trimodular are present in about 17, 69 and 14% of chromosomes, respectively [7]. The C4 gene which is either C4A or C4B can be either a long or short variant depending upon the presence of a 6.36 kb endogenous retrovirus, HERV-K(C4). Pseudogenes or gene fragments are red. CYP21A1* indicates either a CYP21A1P pseudogene or the CYP21A2 gene. In the present study 40 chromosomes from autistic individuals had a C4B null allele. Of these chromosomes 19 were monomodular and 21 were bimodular. In the control subjects with C4B null alleles 10 chromosomes were monomodular and 1 was bimodular. Bimodular C4B null alleles were significantly more frequent in autistic subjects compared to controls (P = 0.0001). No C4B null alleles or CYP21A2 mutations were detected in the subjects (2 autistic, 4 control) with trimodular RCCX modules, determined by protein immunofixation electrophoresis [10].Back to article page