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Biomedical subjects

J I Rotter

Publications and source records attributed to J I Rotter.

At least 127 records · Page 7Linked to original sources
PubMed1986

Uridine monophosphate kinase and susceptibility to invasive Haemophilus influenzae type B disease.

A polymorphic genetic variant of the pyrimidine pathway enzyme, uridine monophosphate kinase-3 (UMPK-3), was positively associated with invasive Hib disease. All UMPK 3-3 homozygotes in this study were Hib cases, and we found that in cases and controls, there was no difference between UMPK phenotype and serum levels of total Hib antibody as measured by radioimmunoassay. This suggests that UMPK-3 may play a role in mediating the non-humoral immunity to Hib. However, unlike other enzyme variants in the nucleoside synthesis pathways which result in syndromes of severe immunodeficiency, this gene appears to confer a more subtle disease susceptibility. Thus, the UMPK-3 allele, although rare in Caucasians, is associated with an increased risk of invasive Hib infection in Alaskan Eskimos.

Alaska↗
PubMed1986

Familial visceral neuropathy with autosomal dominant transmission.

This report describes a family with a visceral neuropathy without extraintestinal manifestations transmitted over at least four generations in an autosomal dominant manner. Four of 7 living patients underwent extensive evaluation including histology, radiography, gastric emptying and secretory studies, esophageal and jejunal manometry, and measurements of plasma levels of gastrointestinal hormones. The only characteristic radiologic abnormality in 7 patients was dilatation of jejunum and ileum. Gastric emptying studies were normal in 2 patients, whereas 2 others showed accelerated emptying of liquids either alone or in combination with grossly delayed solid emptying. Manometry of the esophagus and proximal small intestine and gastric secretory studies were normal. Histologic studies showed hypertrophy of the smooth muscle, a markedly reduced number of argyrophilic neurons, and degenerative changes of argyrophilic neurons and nerve fibers but without Schwann cell proliferation, intranuclear inclusions, or inflammatory cells. This appears to be a familial visceral neuropathy characterized by distinct involvement of the jejunum and ileum as defined radiographically, histology different from that of two previously described forms of familial visceral neuropathy, autosomal dominant transmission, and no evidence for extraintestinal neurologic manifestations.

Adult↗
PubMed1986

Increased intestinal permeability in patients with Crohn's disease and their relatives. A possible etiologic factor.

The cause of Crohn's disease is unknown, although alterations in intestinal permeability may play a primary role. Because we were interested in permeability changes that occur before the onset of intestinal inflammation, we took advantage of the known genetic predisposition to this disease and studied not only patients with Crohn's disease, but their clinically unaffected relatives as well. Intestinal permeability was assessed using the marker polyethylene glycol-400 ingested with a standard meal. We found that 17 normal volunteers absorbed 215 +/- 29.6 mg (mean +/- SE), whereas 11 patients with Crohn's disease absorbed 514 +/- 94.7 mg and their 32 healthy relatives absorbed 566 +/- 62.4 mg. The twofold increase in permeability of patients and their relatives (p less than 0.005 compared with controls) indicates that the intestinal defect in the ability to exclude larger sized molecules is not secondary to clinically recognized intestinal inflammation, but is a primary defect that may be an etiologic factor in this disease.

Adolescent↗
PubMed1986

Relationships between the human pepsinogen DNA and protein polymorphisms.

Pepsinogens (PGA) are the inactive precursors of pepsin, the major acid protease found in the stomach. The PGA gene family exhibits polymorphic variation in human populations that can either be demonstrated by electrophoretic analysis of the proteins or by analysis of the respective genes with cDNA probes. Here, we describe the interrelationships between the most common pepsinogen protein phenotypes and the corresponding pepsinogen haplotypes (A, B, and C) containing different combinations of the PGA3, PGA4, and PGA5 genes. We propose that this unusual genetic variation involving haplotypes that contain three, two, and one genes, respectively, is the result of molecular evolution by gene duplication.

Chromosomes, Human, 6-12 and X↗
PubMed1986

Sample-size considerations and strategies for linkage analysis in autosomal recessive disorders.

The opportunity raised by recombinant DNA technology to develop a linkage marker panel that spans the human genome requires cost-efficient strategies for its optimal utilization. Questions arise as to whether it is more cost-effective to convert a dimorphic restriction enzyme marker system into a highly polymorphic system or, instead, to increase the number of families studied, simply using the available marker alleles. The choice is highly dependent on the population available for study, and, therefore, an examination of the informational content of the various family structures is important to obtain the most informative data. To guide such decisions, we have developed tables of the average sample number of families required to detect linkage for autosomal recessive disorders under single backcross and under "fully informative" matings. The latter cross consists of a marker locus with highly polymorphic codominant alleles such that the parental marker genotypes can be uniquely distinguished. The sampling scheme considers families with unaffected parents of known mating types ascertained via affected offspring, for sibship sizes ranging from two to four and various numbers of affected individuals. The sample-size tables, calculated for various values of the recombination fractions and lod scores, may serve as a guide to a more efficient application of the restriction fragment length polymorphism technology to sequential linkage analysis.

DNA Restriction Enzymes↗
PubMed1986

HLA-dependent GM effects in insulin-dependent diabetes: evidence from pairs of affected siblings.

In a recent study of GM allotype frequencies in HLA-defined subsets of patients with insulin-dependent diabetes mellitus (IDDM) and similarly defined healthy sibling controls, we found evidence for an HLA-dependent GM effect on IDDM susceptibility. To circumvent problems inherent in such patient-control studies of complex diseases, we have now examined sharing of genes in the HLA and GM regions in 26 informative pairs of siblings who were both affected with IDDM. We found that: (1) in the total sample of affected sib-pairs, sharing of two HLA haplotypes was increased compared to Mendelian expectations, in agreement with many previous studies; (2) in the total sample, sharing of GM region genes (as measured by GM phenotype concordance) was not different from Mendelian expectations, given the distribution of parental mating types; and (3) affected sib-pairs who shared two HLA haplotypes showed significantly increased sharing of GM region genes compared to affected sib-pairs who shared one or zero HLA haplotypes (P = .018). These results provide new evidence for HLA-dependent effects of a locus at or near GM on susceptibility to IDDM.

Diabetes Mellitus, Type 1↗
PubMed1985

Uridine monophosphate kinase 3: a genetic marker for susceptibility to Haemophilus influenzae type B disease.

Alaskan Eskimos have the highest known prevalence of invasive Haemophilus influenzae type b (Hib) disease, primarily meningitis, affecting 1-5% of all children in the first two years of life. In this population a polymorphic genetic variant of the pyrimidine pathway enzyme, uridine monophosphate kinase-3 (UMPK-3), was found to be positively associated with invasive Hib disease (relative risk 3.3) and a tendency towards a younger age at onset of illness. There was no difference in levels of naturally acquired Hib anticapsular antibody between persons with Hib disease and healthy controls in this population. This suggests that UMPK-3 may have a role in mediating non-humoral immunity to Hib. However, unlike other enzyme variants in the nucleoside synthesis pathways which result in syndromes of severe immunodeficiency, this gene appears to confer a more subtle disease susceptibility.

Age Factors↗
PubMed1985

A genetic component to the variation of dehydroepiandrosterone sulfate.

Previous studies have shown wide variation in the normal range of serum concentrations of adrenal androgens, including dehydroepiandrosterone (DHA), and DHA sulfate (DHAS). Much of this variability has been shown to be due to the marked variation of the concentrations of these hormones with age. In a search for other sources of this variation, we examined the distribution of DHAS levels in 178 individuals drawn from 26 families. DHAS was chosen because of its relatively high serum concentration, long half-life, and lack of pulsatile variation. As expected, we observed a large age effect, such that it accounted for 68% of the overall variability. In addition, however, when age was factored out by appropriate polynomial regression, there was a significant genetic component to the residual variation, with a heritability of 65%. Thus there appeared to be a significant genetic determination to DHAS serum levels. The results are in accord with previous studies suggesting a genetic component to the variation in testosterone and sex hormone globulin concentrations, and the known correlation of DHAS and testosterone levels. Thus there appears to be significant genetic control of androgen concentrations in humans.

Adolescent↗
PubMed1985

Disease risk estimates from marker association data. Application to individuals at risk for hemochromatosis.

The recessive hemochromatosis gene is both linked to the HLA region on chromosome 6 and nonrandomly associated with certain HLA alleles. The use of linked HLA markers to trace known hemochromatosis genes within a family is well known, but using the population associations to detect unsuspected disease genes has not been fully appreciated. Thus, while HLA typing has been utilized to detect asymptomatic affected siblings, it has not been applied to other relatives. We propose a method in which Bayes' rule is used to calculate the probability that designated HLA marker haplotypes, brought into the family by spouses, have attendant hemochromatosis genes. The A3, B14 and A3, B7 haplotypes are such high risk markers. When these haplotypes are inherited from the unaffected parent, the offspring of an individual with hemochromatosis is at marked increased risk for the disease. When A3 and B14 are absent from the HLA marker haplotype, however, the risk of having a hemochromatosis gene is less than that for the general population. This approach should be helpful in identifying family members at a higher risk for developing the disease and who may then undergo appropriate periodic screening.

Bayes Theorem↗
PubMed1985

Use of HLA marker associations and HLA haplotype linkage to estimate disease risks in families with gluten-sensitive enteropathy.

Based on a two-locus, double recessive model, we derive formulas for the risks that relatives of individuals with gluten-sensitive enteropathy (GSE) will also develop the disease. The calculations take advantage of: the linkage between the HLA locus and one of the two proposed GSE loci, and the preferential association of the HLA-DR3 and DR7 alleles with the GSE disease allele that occupies the HLA-linked locus. We use Bayes' rule to quantitate the strength of the association between the GSE disease allele and the HLA marker allele. This method predicts that siblings of the proband have an overall 10% risk for GSE, which is consistent with observed family data. This predicted risk rises to 30% when siblings are HLA-identical to the proband (also consistent with observed data) or when the sibling has the DR3 allele in the HLA haplotypes not shared with the proband. In those populations where DR7 also is associated with GSE, siblings of probands have a 10% predicted risk for GSE when only one HLA haplotype is shared with the proband and DR7 is included in the unshared haplotype. Other DR alleles are associated with much lower disease risks. By separating individuals into high and low risk groups, HLA typing identifies those individuals who would benefit from further diagnostic procedures. This general strategy should be applicable to other multilocus, marker-associated diseases.

Alleles↗
PubMed1984

Interaction of HLA and immunoglobulin antigens in type 1 (insulin-dependent) diabetes.

We analyzed 88 unrelated subjects with Type 1 (insulin-dependent) diabetes and 64 sibling controls (maximum one per diabetic) for associations between immunoglobulin allotype antigens (GM and KM) and Type 1 diabetes. None were found. However, we did find interactions between GM, HLA-DR, and Type 1 diabetes (significant or of borderline significance after considering the effect of multiple tests): possession of Glm(2) appeared to increase susceptibility to diabetes in individuals who had HLA-DR3 but not HLA-DR4, while possession of G3m(5) appeared to increase susceptibility in individuals who had HLA-DR4 but not HLA-DR3. These results suggest that genetic predisposition to Type 1 diabetes is partially determined by alleles at the GM locus (or a locus in linkage disequilibrium with GM) interacting with alleles at the HLA-DR locus (or a locus in linkage disequilibrium with HLA-DR).

Adult↗