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C Q Edwards

Publications and source records attributed to C Q Edwards.

At least 55 records · Page 3Linked to original sources
PubMed1984

Hypogonadism in hemochromatosis: reversal with iron depletion.

Gonadal function was evaluated in 64 persons homozygous for the HLA-linked hemochromatosis allele. Of 41 men, 10 had reduced libido or impotence and 6 had testicular atrophy. Before treatment, 5 men had below normal testosterone concentrations, 4 of whom also had low gonadotrophin levels. Four hypogonadal men were reevaluated after iron depletion treatment. In 2, 1 with primary and another with secondary hypogonadism, testosterone levels returned to normal after phlebotomy and were accompanied by a return of normal sexual function. None of 23 women with hemochromatosis had loss of libido or had a natural menopause before age 45. Our findings indicate that in some men with hereditary hemochromatosis and hypogonadism of either testicular or central origin, sexual function and sex hormone concentrations can be restored to normal after iron depletion therapy.

Adolescent↗
PubMed1983

The genetics of quantitative plasma Lp(a): analysis of a large pedigree.

Likelihood analysis using the mixed model of quantitative plasma Lp(a) measurements on members of a large pedigree provided evidence that high levels of Lp(a) are inherited as a dominant major gene with polygenic background. The dominant allele frequency was estimated as 0.10. The major gene and polygenic components together accounted for 95% of the variation seen in the measurements. The major gene index and OBP plots, methods that do not allow for the presence of both components, favored the polygenic model over the major gene model as the mode of inheritance. No association was found with any of the lipids, lipoproteins or apolipoproteins considered.

Female↗
PubMed1983

Phenotypic heterogeneity in the extended pedigree of a proband with lipoprotein lipase deficiency.

We have studied the large nonconsanguineous pedigree of a proband with Type I hyperlipoproteinemia (HL) and lipoprotein lipase (LPL) deficiency. Within the nuclear family, the mother and two of the proband's five siblings had fasting hypertriglyceridemia or low-normal tissue adipose LPL activities or both. Retention of lipoprotein retinyl esters after vitamin A feeding was present only in the propositus. The maternal side of the extended pedigree contained individuals with Types IIA, IV, and V hyperlipoproteinemia, findings most consistent with autosomal dominant multiple lipoprotein-type hyperlipidemia (familial combined hyperlipidemia). This family and previously reported pedigrees of Type I HL probands have demonstrated phenotypic heterogeneity. Without specific genetic markers, homozygous LPL deficiency and complex multiple-gene mechanisms cannot be distinguished unambiguously. Parental hyperlipidemia in nuclear pedigrees of Type I HL probands should not be equated with heterozygous LPL deficiency in the absence of extended pedigree data or more informative markers. The possibility that the complex inheritance of two different genetic defects in lipoprotein transport can produce the Type I HL phenotype must be considered.

Adipose Tissue↗
PubMed1983

Thyroid disease in hemochromatosis. Increased incidence in homozygous men.

The thyroid function of 49 patients homozygous for the hemochromatosis allele was studied by measurement of serum thyroxine and thyrotropin concentrations. Of 34 homozygous men, three were found to be hypothyroid (thyroxine, less than 3.0 micrograms/dL and thyrotropin, greater than 40 ImU/mL) and one was hyperthyroid (thyroxine, 24 micrograms/dL). All 15 homozygous women had normal thyroid function. The hypothyroid patients had elevated titers of antithyroid antibodies. Histologic examination of the thyroid at autopsy of one hypothyroid patient showed notable iron accumulation and fibrosis with modest lymphocytic infiltration. The causative importance of iron deposition in thyroid diseases associated with hemochromatosis was suggested by the reversal of the usual sex ratio of thyroid dysfunction. Men with hemochromatosis had a much greater iron load than women, and they also had a surprisingly higher incidence of thyroid disease. Iron may have caused injury to the thyroid, followed by the development of antithyroid antibodies and hypothyroidism. The frequency of thyroid disorders in men with hemochromatosis is about 80 times that of men in the general population.

Adult↗
PubMed1982

Iron overload in hereditary spherocytosis: association with HLA-linked hemochromatosis.

Heavy iron loading is a rare clinical finding in patients with hereditary spherocytosis. A pedigree was studied in which the proband, a 38-year-old man, had both hereditary spherocytosis and overt hemochromatosis. He had never received blood transfusions. The 8-year-old son of the proband also had hereditary spherocytosis and mildly increased iron stores. The 39-year-old brother of the proband did not have spherocytosis but did have overt hemochromatosis. Since hemochromatosis is transmitted as an HLA-linked autosomal recessive disorder, HLA haplotypes serve as markers of hemochromatosis alleles. In this pedigree only individuals with two hemochromatosis alleles (homozygosity) had heavy iron loads, whether hereditary spherocytosis was present or not. The presence of hereditary spherocytosis may have contributed to the magnitude of the iron loading but was not a major factor. Our findings suggest that nontransfusional hemochromatosis found in association with hereditary spherocytosis is due primarily to homozygosity for hemochromatosis.

Adult↗
PubMed1982

Hereditary hemochromatosis. Analysis of laboratory expression of the disease by genotype in 18 pedigrees.

Tight linkage between the hemochromatosis locus and the HLA region permits determination of genotype in members of hemochromatosis pedigrees. To determine if simple laboratory measures of iron metabolism could predict the affected genotype without the need for HLA typing, we studied seven measures of iron metabolism: serum iron concentration, total iron-binding capacity, per cent saturation of transferrin, serum ferritin concentration, deferoxamine-induced urinary iron excretion and hepatic iron concentration evaluated by both chemical and histological methods. Discriminant analysis showed a per cent saturation of transferrin above 62% to be the best simply-measured indicator of the affected genotype: homozygosity is accurately predicted in 92% of the cases. The logarithmic transform of serum ferritin concentration was only 71% accurate. Pedigree analysis estimated the frequency of the hemochromatosis gene at 0.069 +/- 0.020 with a recombination probability of 0.015 +/- 0.015 with the HLA region. This corresponds to a heterozygote frequency of 0.13 and a disease frequency of 0.005.

Age Factors↗
PubMed1982

Familial effects on plasma sex-steroid content in man: testosterone, estradiol and Sex-hormone-binding globulin.

We investigated whether familial factors influence the plasma content of sex-steroids and sex-hormone-binding globulin (SHBG) in 98 adult males of 66 families. They had no apparent endocrine dysfunction, The 0800-1100 hr plasma levels of testosterone, 5 alpha-dihydrotestosterone (DHT), estradiol-17 beta (E2) and estrone (E1) were measured by radioimmunoassay. The free fractions of E2 and testosterone were determined by equilibrium dialysis, and binding capacity of SHBG was also calculated. The data were analyzed by analysis of variance. We observed that the differences in the plasma content of testosterone (p = .02). SHBG binding capacity (p = 0.1), and E2 (p = 0.3), free E2 index (p = .05) were all substantially less variable within groups of brothers than among non-brothers. The variability of the plasma concentration of DHT, free testosterone and E1 was not significantly less within brothers than among non-brothers. The correlation between either plasma testosterone content (r = .14) or SHBG binding capacity (r = .12) and percent of ideal body weight was not significant statistically. Age had no effect on the results. Our data suggest that genetic and/or environmental factors may affect the plasma content of testosterone, E2 and SHBG binding capacity.

Adult↗
PubMed1981

Coincidental nontransfusional iron overload and thalassemia minor: association with HLA-linked hemochromatosis.

A pedigree was studied in which five individuals with beta-thalassemia minor were found to have nontransfusional hemochromatosis. Three were children under the age of 10 and two were young male adults, ages 28 and 33. A 5-yr-old child without evidence of thalassemia also had hemochromatosis. Since hemochromatosis is transmitted as an HLA-linked autosomal recessive disorder, HLA haplotypes serve as markers of hemochromatosis alleles. In this pedigree, five identifiable HLA haplotypes were associated with hemochromatosis alleles. Only individuals with two hemochromatosis alleles (homozygosity) had heavy iron loads, whether beta-thalassemia minor was present or not. Individuals with beta-thalassemia minor but without a hemochromatosis allele had normal transferrin saturation. A 65-yr-old man with beta-thalassemia minor and a single hemochromatosis allele had only a minimally elevated transferrin saturation (54%). The presence of beta-thalassemia minor did not appear to accentuate the degree of iron loading expected in individuals homozygous or heterozygous for hemochromatosis alleles. Our findings suggest that nontransfusional hemochromatosis found in association with beta-thalassemia minor is due primarily to homozygosity for hemochromatosis.

Adolescent↗
PubMed1980

Genetic mapping of the hemochromatosis locus on chromosome six.

The purpose of this paper is to report a pedigree with hereditary hemochromatosis in which a recombination between the HLA-A and B loci occurred. Both the maternal and paternal HLA-A3, B7 haplotypes were carrying an allele for hemochromatosis. The A3, B12 haplotype of the proband was a recombinant of the maternal A3, B7 and A28, B12 haplotypes. The hemochromatosis locus segregated with the HLA-A locus and not with the HLA-B locus. Thus, the hemochromatosis locus maps in close proximity to the HLA-A locus.

Adult↗
PubMed1980

Association of HLA-linked hemochromatosis with idiopathic refractory sideroblastic anemia.

Five of seven patients with idiopathic refractory sideroblastic anemia carried an HLA-A3 alloantigen (relative risk, 7.3; P = 0.02). The significance of this association was strengthened by study of two pedigrees. An abnormality in iron metabolism was found in two siblings who had an HLA-A3,B14 haplotype in common with the first proband. A second proband with idiopathic refractory sideroblastic anemia had clinically manifest hemochromatosis. His brother had clinically manifest hemochromatosis but not sideroblastic anemia. This proband and his brother shared only the HLA-A3,B12 haplotype. Our findings infer that patients with idiopathic refractory sideroblastic anemia carry a single allele for hemochromatosis, that this allele accounts for the increased iron loading in this form of anemia, and that clinically manifest hemochromatosis may develop in an occasional patient with only one allele for hemochromatosis in the presence of the sideroblastic factor.

Adult↗
PubMed1980

Homozygosity for hemochromatosis: clinical manifestations.

We identified 35 homozygotes for hemochromatosis through pedigree studies. Thirteen were asymptomatic. Arthropathy was present in 20, hepatomegaly in 19, transaminasemia in 16, skin pigmentation in 15, splenomegaly in 14, cirrhosis in 14, hypogonadism in six, and diabetes in two. No homozygote was in congestive failure. Only one had the triad of hepatomegaly, hyperpigmentation, and diabetes. Serum iron was increased in 30 of 35, transferrin saturation was increased in all 35, serum ferritin in 23 of 32, urinary iron excretion after deferoxamine in 28 of 33, hepatic parenchymal cell stainable iron in 32 of 33, and hepatic iron in 27 of 27. Iron loading was 2.7 times greater in men than in women. No female had hepatic cirrhosis. Diagnosis of asymptomatic hemochromatosis is important because organ damage may be prevented by early therapy. Clinical diagnosis of early hemochromatosis is difficult. Persons with unexplained elevation of transferrin saturation should be studied for hemochromatosis.

Adolescent↗
PubMed1979

Hereditary hemochromatosis. Phenotypic expression of the disease.

Previous studies have shown that hemochromatosis is an inherited, autosomal-recessive disease and that the gene is closely linked to the HLA locus on chromosome 6. We obtained a lod score for linkage of +9.8 for a recombination fraction of 0.0 and a gene frequency of 0.056, the frequency estimated in this population. We studied the phenotypic expression of the disease in 261 members of 10 pedigrees. In heterozygotes over 20 years of age, there was an intermediate increase in transferrin saturation and a limited increase in hepatic iron but no clinical manifestations. In male heterozygotes, the average amount of iron in the liver increased from about 0.2 to 1.3 g. Abnormal homozygotes accumulated iron progressively with time, with men accumulating about 18 g in the liver. All measurements of iron status were increased in abnormal homozygotes. Hemochromatosis is inherited as an autosomal-recessive disease, with partial biochemical expression in heterozygotes.

Adolescent↗
PubMed1979

Hereditary hypoceruloplasminemia.

Serum ceruloplasmin values of less than 21.0 mg/100 ml in males or less than 23.0 mg/100 ml in females were observed in 14 out of 156 otherwise healthy members of a pedigree. The hypoceruloplasminemia segregated in a fashion suggesting that the affected individuals are heterozygous for a mutant gene that results in hypoceruloplasminemia. This mutant gene could be a Wilson's disease gene, but excessive copper loading was absent. It is suggested that hereditary hypoceruloplasminemia may be a benign entity distinct from Wilson's disease.

Adolescent↗
PubMed1978

Nephrotoxicity induced by gentamicin and amikacin.

We evaluated 124 patients for nephrotoxicity associated with gentamicin or amikacin therapy. The incidence of definite nephrotoxicity was 10.5% during therapy, with a mean increase in creatinine of 1.0 mg/100 ml (range, 0.5-3.6 mg/100 ml). Nephrotoxicity developed late in therapy (mean, day 10) and the creatinine continued to increase after cessation of therapy for as long as nine days. Age, initial creatinine, total dose and initial "peak" and "valley" levels did not correlate with nephrotoxicity. Nephrotoxicity developed in 8 of 97 patients treated for less than or equal to 11 days and 5 of 19 treated for greater than 11 days (chi square, p less than .01). "Peak" and "valley" levels rose significantly (t-test, p less than .05) during therapy and increased more in those with nephrotoxicity. A "peak" level of amikacin of greater than or equal to 38.5 micrometer/ml or of gentamicin of greater than or equal to 10 micrometer/ml or a rise in the "valley" levels of amikacin above 10 micrometer/ml was also associated with nephrotoxicity (chi square, p less than .025). These data help define the natural history and the host and drug factors that affect the development of gentamicin- and amikacin-induced nephrotoxicity.

Adult↗