Biomedical subjects
Publications and source records attributed to R C Go.
The factor B BfF allele was found significantly less frequently in nonobese black women with gestational diabetes mellitus than in the control group. The BfS allele was found more frequently, although not significantly so. These data suggest similar genetic associations among nonobese black women with gestational diabetes mellitus and those with insulin-dependent diabetes mellitus.
Impaired immune defense mechanisms and genetic factors appear to play a role in susceptibility to acute necrotizing ulcerative gingivitis (ANUG). Therefore, possible etiological mechanisms might involve genes at the Major Histocompatibility Complex, which include the complement factor loci. We have tested for a possible association between certain complement factor alleles and ANUG using a case-control study design. Specific alleles at complement factors C3 and C4, and properdin factor B (Bf) loci were determined indirectly by high voltage agarose gel electrophoresis in 58 subjects with a history of ANUG and in 58 age-sex-matched healthy controls. The highest relative risk of ANUG, as obtained by conditional logistic regression, for alleles at the C3 locus was 1.9 (90% confidence limits 0.8 to 4.8; p = 0.229) for C3*F-positive individuals. The highest relative risk for alleles at the C4 locus was 2.6 (0.5 to 14.9; p = 0.358) for C4A*3-positive individuals. There was no evidence for an association between Bf allotype and risk of ANUG, with a relative risk of 1.2 for Bf*F- and relative risk of 1.0 for B*S-positive individuals. None of our estimates was statistically significant. We conclude, therefore, that it is unlikely that there is any association between complement factor gene haplotype and susceptibility to ANUG.
Families with multiple cases of seropositive rheumatoid arthritis (RA), identified through 2 probands with the disease, were analyzed for genetic linkage between an autosomal susceptibility gene for RA and the HLA loci. These analyses were carried out over a wide range of penetrances (0.1-0.4), with prevalence for the disease fixed at 0.01 or 0.04. In some models, a sporadic frequency of 20% was assumed. Close linkage to the HLA loci was ruled out for all models where the gene was autosomal dominant, except for those with low penetrance and with prevalence set at 0.04. The models in which the gene was autosomal recessive produced results similar to those in models where it was autosomal dominant when prevalence was set at 0.01, and close linkage was ruled out, except at very low penetrances. With prevalence set at 0.04, the autosomal recessive gene model produced log odds scores which were all negative (-2.6 to -0.3). Therefore, the evidence in these families does not support close linkage with HLA, even though a significant DR4 RA population association exists. The data suggest that non-major histocompatibility complex (MHC) genes may contribute to the development of RA and, therefore, disease susceptibility may involve the genetic interaction of one or more MHC genes and non-MHC genes, in addition to environmental agents.
We studied the patterns of in vitro IgM RF production by peripheral blood mononuclear leukocytes (MNL) in first- and second-degree relatives and non-blood relatives of 14 RA patients. In all these included 25 individuals with RA (14 probands, 11 other affected members), 88 non-affected first- and second-degree relatives and 15 non-affected non-blood relatives. In vitro production of IgM RF and IgM by MNL from RA patients was similar to what we and others have previously described. Spontaneous production of IgM RF was demonstrated by MNL from some RA patients and the ratio of IgM RF to total IgM was higher for patients than controls. The non-blood relatives failed to demonstrate spontaneous in vitro IgM RF production. In contrast, MNL from approximately 16% of non-affected blood relatives spontaneously produced IgM RF. Spontaneous IgM RF production in this group did not correlate with HLA-DR3 or HLA-DR4 and was found in Caucasoids. American blacks, simplex (one affected individual), and multiplex (more than one affected individual) families. Linkage analysis using either a recessive or dominant model of inheritance failed to detect linkage among affected and non-affected family members.
After standardization for age and menopausal status, the prevalence of estrogen receptor positivity among 88 White breast cancer patients was about .72 compared with a prevalence of about .54 among Black patients. The prevalence of progesterone receptor positivity was also higher among White than among Black patients, although the magnitude of the difference was smaller. These differences were unchanged after adjustment for tumor size and nodal and distant metastases in addition to age and menopausal status.
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This study was undertaken to determine whether defects in leukocyte function or in genes at the MHC play a role in the etiology of either localized (LJP) or generalized (GJP) juvenile periodontitis. Thirteen LJP and five GJP patients (ranging in age from 13 to 22 years) and their matched controls were compared with respect to selected leukocyte functions and HLA phenotypic frequencies. The results of these studies indicated that there were significant decreases in the phagocytic and chemotactic abilities of polymorphonuclear leukocytes (PMN) in both LJP and GJP. All JP patients displayed intrinsic cell defects in chemotaxis compared with controls; in addition, some patients displayed multiple defects, including those which were serum-associated. Also, there appeared to be a significant association between JP and HLA-DR2 and HLA-A33 phenotypes. Fifty percent of the JP patients were HLA-DR2-positive, whereas only six percent of the matched controls were positive. Thirty-six percent of JP patients were HLA-A33-positive, whereas none of the controls was positive. The association seen with DR2 may be due to sampling, since there were no significant differences between the JP cases and a larger unmatched control sample which was not evaluated for periodontal disease. We conclude from these data that increased susceptibility of some patients to a very aggressive and destructive form of periodontal disease (JP) is based on defects in PMN responsiveness. Further investigations are necessary to determine whether these defects are under genetic control.
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The complement component C4 variants C4A 4, C4B 4 and C4B Q0 were found to be significantly increased in 64 black patients with Type 1 (insulin-dependent) diabetes compared with 169 black control subjects, yielding relative risks of 3.3, 2.9 and 3.4, respectively. The increased frequencies of C4B 4 and C4B Q0 in black Type 1 diabetic patients are similar to those found in Caucasoid Type 1 diabetic patients. The data suggest that Type 1 diabetes in black Americans may be partially due to admixture of genes from whites.
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Von Hippel Lindau disease (vHL), an autosomal dominant precancerous condition, had segregated in a large kindred. Fourteen relatives were known to have been affected; record reviews disclosed features of vHL in 15 previously undiagnosed relatives; presymptomatic evaluations detected vHL in 13 additional members of this kindred. Altogether, among 220 descendants of an ancestral couple, 41 had vHL. We screened for HLA haplotypes and for polymorphic gene markers at 31 loci in 102 direct descendants and 16 spouses from this kindred, including 23 with vHL. Linkage analyses failed to reveal a significant lod score with any locus tested, or any HLA linkage disequilibrium. Expression of vHL among the affected relatives was compared with 384 other reported cases of vHL. The age of onset, tissue involvement, and life expectancy in this family were similar to the other reported cases. The sigmoid age-of-onset distribution for vHL most closely matched a square-foot transformation (mean = 26.2(-2) years; variance = 1.224).
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In order to try to detect heterogeneity within insulin dependent diabetes mellitus (IDDM) and to distinguish a mode of inheritance of IDDM, population genetic analyses were performed using HLA allele frequencies. HLA-A and -B typing performed on 231 IDDM individuals and 268 controls from the southeastern U.S. showed significant increases with IDDM in A2, B8, B15 and B18, and significant decreases in Aw23, B7, B14 and B17. The combination of HLA-B8/B15 showed a greatly increased risk (RR = 25.5). Between the 120 IDDM individuals and 123 controls HLA-DR typed, HLA-DR3 and -DR4 were significantly increased among the IDDM group and DR2 and DR7 were decreased. The risk for DR3/4 was 29.2. It appeared that the B15 association was secondary to the DR4, but the B8/DR3 association showed no difference. Using the method of Curie-Cohen, no significant increases in risk were found for the B8/B15 or DR3/DR4 heterozygotes when compared to the respective homozygotes. Using the method of Thomson and Bodmer, the dominant mode of inheritance was excluded for DR4 only. There was a significant increase in B15 and DR4 in those with onset before age 20. No significant differences were found among the DR phenotypes with respect to season.
C4 is composed of two tightly linked genes (C4A and C4B) lying within the major histocompatibility complex of chromosome 6 that can be demonstrated by agarose gel electrophoresis. Seven alleles and five alleles at the C4A and C4B loci, respectively, were detected in 169 black individuals from the southeastern United States. Furthermore, the phenotypic frequencies of C4A6, C4A5, C4A4, C4B4, C4B3 and C4BQ0 were significantly different between black and white Americans.
The present study combines segregation and linkage information on 30 families ascertained through a proband and a first degree relative affected with insulin-dependent diabetes mellitus (IDDM). An autosomal dominant model with incomplete penetrance was much more likely to fit the family data than a recessive model, whether or not linkage to HLA was assumed. The lod scores for linkage to HLA were 2.46 at theta M = theta F = 0.00 for dominant and 1.45 at theta M = theta F = 0.22 for a recessive model. The results are discussed in light of heterogeneity in likelihood and lod scores when the families are grouped by familial types, which indicate that the increase in likelihood of a dominant hypothesis can be attributed to the parent-child families and not the sib-sib families.
Genetic and environmental hypotheses that might explain the patterns of occurrence of breast cancer and associated cancers in 18 large families at high risk of the disease were tested with the use of segregation analysis. For 16 pedigrees, results were consistent with the hypothesis that breast cancer has a genetic etiology. In 2 other families, breast cancer appeared more likely to have an environmental origin. Breast cancer susceptibility is best explained by hypotheses that postulate autosomal dominant susceptibility alleles in 10 families with primarily premenopausal breast cancer and ovarian cancer, in 4 families with primarily postmenopausal breast cancer, and in 2 families with breast cancer, brain tumor, sarcoma, leukemia, and adrenocortical carcinoma in children and young adults. In an accompanying paper, genetic susceptibility in the first 2 groups of families is further explored with the use of linkage analysis.
Chromosomal locations of hypothetical alleles which increase susceptibility to human breast cancer in some families were investigated by genetic linkage analysis. In 7 families with primarily premenopausal breast cancer and (in 5 families) ovarian cancer, a dominant susceptibility allele may be linked to the genetic marker glutamicpyruvic transaminase or alanine aminotransferase (GPT; lod score 1.95 at zero recombination). The most positive lod score for linkage to a recessive susceptibility allele was for acid phosphatase (ACP; lod score 0.78 at 40% recombination), but ACP was informative in ony 1 family. In 3 families with primarily postmenopausal breast cancer, none of 21 genetic markers provided any evidence for linkage to either dominant or recessive susceptibility alleles. In the families with the possible GPT linkage, women who carry the hypothetical susceptibility allele would be at high risk of breast cancer, whereas their relatives who do not carry that allele would have no increased risk. GPT genotype is not associated with breast cancer risk in the general population, so GPT linkage cannot be used as a screening test for breast cancer.
One hundred-sixty-four ALL patients were compared to 545 controls for differences in phenotype and gene frequencies at the Properdin factor B locus. In addition, 90 of the ALL patients were immune phenotyped. A significant association with the Bf F allele and ALL was found, resulting in an estimated relative risk of 3.62. There was no difference in the Bf S phenotype between ALL patients and controls. However, those homozygous for the Bf S allele are at a significantly low risk of 0.30 for developing ALL. ALL patients with a non-B/T cell type were 2.5 times more likely to be Bf SS homozygotes; in contrast, those patients with the pre-B cell type were 2.5 more likely to be Bf FF homozygotes. These data suggest association of the Bf locus with an ALL protection and/or susceptibility gene(s).