Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Certain alleles for the complement proteins, C4 and Bf, have been shown to be markers for insulin-dependent diabetes mellitus (IDDM) in samples of different racial and geographic composition. However, the same markers are not demonstrable in each group studied. Phenotyping for the complement alleles, C4 and Bf was performed on 168 Caucasian and 49 Black patients with IDDM. All of the patients were followed in Memphis, Tennessee and had onset of disease prior to age 18. The Bf*F1 allelic frequency was significantly increased for the Caucasian patients as compared to 93 healthy Caucasian controls (0.063 vs. 0.016) and for the Black IDDM patients as compared to 43 healthy Black controls (0.102 vs. 0.035). C4 phenotype frequencies showed a significant increase of the C4AQ0 (rr = 2.13) and C4A4 (rr = 2.91) phenotypes for the Caucasian IDDM patients as compared to controls, but the frequency of homozygous null C4A was not significantly increased. In addition significant negative associations of IDDM with C4A3 and C4A6 phenotypes and no association with any C4B phenotype were observed in our Caucasian patient population. Our data for Mild-South Blacks with IDDM suggest a similar positive association of IDDM with the BfF1 phenotype (rr = 3.4). However, there was no evidence among Black IDDM patients of the C4AQ0 and C4A4 associations observed in the Caucasian sample. The data support a possible association of IDDM with the C4A2 (rr = 5.86) and C4B2 (rr = 5.26) phenotypes. The hypothesis that racial admixture may account for the higher frequency of IDDM in US Blacks as compared with African Blacks has been forwarded by others.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:C4 and Bf phenotypes in black and Caucasian patients with childhood onset insulin dependent diabetes mellitus. 264 74

Class III gene rearrangements have been examined in Thai/Chinese individuals with supratypes bearing defective or null C4 alleles. Genomic DNA from C4 null supratypes was probed with an almost full-length 21-OH probe following digestion with Taq I and Kpn I. The HLA-B17 C4A3 BQ0 BfS DR3 Thai/Chinese supratypes (which may be associated with insulin-dependent diabetes mellitus in Orientals) lacks a 3.2 kb Taq I and a 3.9 kb Kpn I fragment hybridizing with the 21-OH probe. Similar gene rearrangements are found in Caucasoid diabetogenic supratypes HLA-B18 C4A3 BQ0 BfF1 DR3 and HLA-B8 C4AQ0 B1 BfS DR3. Interethnic comparisons suggest that class II and class III interactions may be important in disease susceptibility. By contrast, neither of two Thai/Chinese supratypes with C4AQ0 appear to have major class III gene rearrangements; disease association studies will determine the significance of C4 deficiency per se. As in Caucasoids, the electrophoretically fast C4 allele, C4A6, in Orientals has been shown to correlate with a 12 kb Bgl II fragment hybridizing with a C4 probe. It is likely that the HLA-B17 C4A6 B1 BfS DR7 supratype marks a highly conserved MHC chromosomal segment.
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PMID:Class III gene rearrangements in Thai/Chinese supratypes containing null or defective C4 alleles. 333 23

The fourth component of complement (C4) in man, is coded for by two separate but closely linked loci (C4A and C4B) within the major histocompatibility region (MHC), on the short arm of chromosome 6. Like class I and II loci of this region, the C4 genes are highly polymorphic with more than 30 alleles, including null alleles, assigned to the two loci. This extensive polymorphism, based mainly on electrophoretic mobility, provides a useful marker for studies of disease susceptibility. Several disorders, including systemic lupus erythematosus and type I diabetes, show associations with C4 phenotypes. We have used the technique of Southern with a C4 specific probe to examine the genomic DNA of individuals typed for C4 by protein electrophoresis. We have identified 10.7 and 3.8 kilobase (kb) BglII restriction fragments in each of 9 unrelated individuals with a C4A6 allele, and in none of 22 unrelated individuals in whom this allele was not expressed. This clear correlation of restriction fragment length polymorphism with C4 phenotype provides a precise basis for analysis of C4 polymorphism. It is likely to be of value in clinical investigations of autoimmune disease.
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PMID:Correlation between a DNA restriction fragment length polymorphism and C4A6 protein. 631 64