James C Barton

University of Alabama at Birmingham, Birmingham, AL, United States

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Publications (197)900.36 Total impact

  • James C Barton
    The American Journal of the Medical Sciences 11/2013; 346(5):403-12. · 1.33 Impact Factor
  • James C Barton, J Clayborn Barton
    The journal of vascular access 09/2013; · 1.02 Impact Factor
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    ABSTRACT: Objective We sought to identify predictors of diabetes diagnosed before hemochromatosis.Research Design and Methods We studied these 16 variables in 159 non-screening hemochromatosis probands with HFE C282Y homozygosity: age; sex; body mass index (BMI); diabetes reports in first-degree family members (dichotomous); heavy ethanol consumption; cigarette smoking; elevated serum ALT/AST levels; non-alcoholic fatty liver; chronic viral hepatitis; cirrhosis; hand arthropathy; iron removed by phlebotomy; and positivity for HLA-A*01, B*08; A*03, B*07; and A*03, B*14 haplotypes. We performed univariable and multivariable analyses.ResultsTwenty-three probands (14.5%) had diabetes; 19 were men. Each of the 23 probands had type 2 diabetes. Mean BMI was greater in probands with diabetes (31.7 ± 8.5 (SD) kg/m(2) vs. 27.6 ± 5.1 kg/m(2); p = 0.032). Reports of any first-degree family member with diabetes were more prevalent in probands with than in probands without diabetes (69.6% vs. 17.6%; p <0.0001). In probands with diabetes, the odds ratio (OR) of maternal diabetes was 6.7 ((95% CI 2.3, 19.7); p = 0.0005) and of sibling diabetes was 11.7 ((95% CI 3.0, 45.5); p = 0.0004). In a logistic regression model, predictors of diabetes at hemochromatosis diagnosis in 159 probands were diabetes reports in family members (OR 8.5 (95% CI 2.9, 24.8); p<0.0001) and BMI (OR 1.1 (1.0, 1.2); p=0.049). This model explained 26.0% of total deviance contributing to diabetes.Conclusions In non-screening hemochromatosis probands with HFE C282Y homozygosity, a heritable factor(s) increases the risk of diabetes diagnosed before hemochromatosis.
    Diabetes care 08/2013; · 7.74 Impact Factor
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    ABSTRACT: Many patients referred for an elevated serum ferritin level <1000 µg⁄L are advised that they likely have iron overload and hemochromatosis. To determine the prevalence of HFE mutations in the hemochromatosis gene for 11 serum ferritin concentration intervals from 200 µg⁄L to 1000 µg⁄L in Caucasian participants in a primary care, population-based study. The Hemochromatosis and Iron Overload Screening study screened 99,711 participants for serum ferritin levels, transferrin saturation and genetic testing for the C282Y and H63D mutations of the HFE gene. This analysis was confined to 17,160 male and 27,465 female Caucasian participants because the HFE C282Y mutation is rare in other races. Post-test likelihood was calculated for prediction of C282Y homozygosity from a ferritin interval. A subgroup analysis was performed in participants with both an elevated serum ferritin level and transferrin saturation. There were 3359 male and 2416 female participants with an elevated serum ferritin level (200 µg⁄L to 1000 µg⁄L for women, 300 µg⁄L to 1000 µg⁄L for men). There were 69 male (2.1%) and 87 female (3.6%) C282Y homozygotes, and the probability of being a homozygote increased as the ferritin level increased. Post-test likelihood values were 0.3% to 16% in men and 0.3% to 30.4% in women. Iron loading HFE mutations are unlikely to be the most common cause of an elevated serum ferritin level in patients with mild hyperferritinemia. Patients should be advised that there are many causes of an elevated serum ferritin level including iron overload.
    Canadian journal of gastroenterology = Journal canadien de gastroenterologie. 07/2013; 27(7):390-2.
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    ABSTRACT: Hereditary Hemochromatosis (HH) is a recessively inherited disorder of iron overload occurring commonly in subjects homozygous for the C282Y mutation in HFE gene localized on chromosome 6p21.3 in linkage disequilibrium with the human leukocyte antigen (HLA)-A locus. Although its genetic homogeneity, the phenotypic expression is variable suggesting the presence of modifying factors. One such genetic factor, a SNP microhaplotype named A-A-T, was recently found to be associated with a more severe phenotype and also with low CD8(+)T-lymphocyte numbers. The present study aimed to test whether the predictive value of the A-A-T microhaplotype remained in other population settings. In this study of 304 HH patients from 3 geographically distant populations (Porto, Portugal 65; Alabama, USA 57; Nord-Trøndelag, Norway 182), the extended haplotypes involving A-A-T were studied in 608 chromosomes and the CD8(+) T-lymphocyte numbers were determined in all subjects. Patients from Porto had a more severe phenotype than those from other settings. Patients with A-A-T seemed on average to have greater iron stores (p = 0.021), but significant differences were not confirmed in the 3 separate populations. Low CD8(+) T-lymphocytes were associated with HLA-A*03-A-A-T in Porto and Alabama patients but not in the greater series from Nord-Trøndelag. Although A-A-T may signal a more severe iron phenotype, this study was unable to prove such an association in all population settings, precluding its use as a universal predictive marker of iron overload in HH. Interestingly, the association between A-A-T and CD8(+) T-lymphocytes, which was confirmed in Porto and Alabama patients, was not observed in Nord-Trøndelag patients, showing that common HLA haplotypes like A*01-B*08 or A*03-B*07 segregating with HFE/C282Y in the three populations may carry different messages. These findings further strengthen the relevance of HH as a good disease model to search for novel candidate loci associated with the genetic transmission of CD8(+) T-lymphocyte numbers.
    PLoS ONE 01/2013; 8(11):e79990. · 3.53 Impact Factor
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    ABSTRACT: HFEC282Y homozygotes have an increased risk for developing increased iron stores and related disorders. It is controversial whether dietary iron restrictions should be recommended to such individuals. To determine whether dietary iron content influences iron stores in HFEC282Y homozygotes as assessed by serum ferritin concentration. Serum ferritin concentration was measured and a dietary iron questionnaire was completed as part of the evaluation of 213 HFEC282Y homozygotes who were identified through screening of >100,000 primary care patients at five HEmochromatosis and IRon Overload Screening (HEIRS) Study Field Centers in the United States and Canada. No significant relationships between serum ferritin concentration and dietary heme iron content, dietary nonheme iron content or reports of supplemental iron use were found. These results do not support recommending dietary heme or nonheme iron restrictions for HFEC282Y homozygotes diagnosed through screening in North America.
    Canadian journal of gastroenterology = Journal canadien de gastroenterologie 06/2012; 26(6):345-9. · 1.53 Impact Factor
  • Pauline L Lee, Terry Gaasterland, James C Barton
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    ABSTRACT: We report on a 46-year-old black man who resided in Alabama with normal transferrin saturation, mild hyperferritinemia, chronic hepatitis C, and 3+ iron in hepatocytes and Kupffer cells. Exome sequencing revealed heterozygosity for SLC40A1 D270V (exon 7, c.809A→T), a mutation previously reported only in 1 black patient with iron overload who resided in the Republic of South Africa. The present patient was also heterozygous for: heme transporter FLVCR1 novel allele P542S (exon 10, 1624C→T); FLVCR1 T544M (rs3207090); hemopexin (HPX) R371W (rs75307540); ferritin scavenger receptor (SCARA5) R471H (rs61737287); and transferrin receptor (TFRC) G420S (rs41295879). He had no HFE, TFR2,HJV, or HAMP mutations. D270V was not detected in 19 other African Americans with iron overload who resided in Alabama. The allele frequency of SLC40A1 D270V in 258 African American adults who participated in a health appraisal clinic was 0.0019 (95% confidence interval 0-0.0057). D270V could explain 'classical' ferroportin hemochromatosis phenotypes in some African Americans.
    Acta Haematologica 05/2012; 128(1):28-32. · 0.89 Impact Factor
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    ABSTRACT: We sought to determine predictors of shingles reports in adults with common variable immunodeficiency or immunoglobulin (Ig) G subclass deficiency (CVID/IgGSD). We tabulated observations at diagnosis of CVID/IgGSD in 212 white adult index patients (165 women, 47 men) who responded to a question about having had shingles. None had been vaccinated for herpes zoster. We analyzed age, sex, and shingles reports; blood levels of CD19+, CD4+, CD8+, and CD56+ mononuclear cells; serum levels of IgG subclasses, IgA, and IgM; and positivity for human leukocyte antigen (HLA)-A and -B haplotypes. Cell counts and immunoglobulin levels were normalized with loge (ln) transformation for analyses. Thirty-one patients (14.6%) reported shingles; 11 reported recurrent or disseminated shingles. Patients with shingles reports had greater mean age at diagnosis of CVID/IgGSD [54±13 (standard deviation) years vs. 47±12 years; P=0.0130] and a greater prevalence of HLA-A*01, B*08 positivity (35.5% vs. 17.7%; P=0.0227). In a 13-factor logistic regression model, there was a positive association of age with shingles reports [P=0.0151; odds ratio (1.05, 95% confidence interval 1.01, 1.08)]. HLA-A*01, B*08 positivity was also positively associated with shingles reports [P=0.0480; odds ratio 2.61 (1.00, 6.81)]. During a mean followup interval of 7.5 years after CVID/IgGSD diagnosis, the prevalence of recurrent shingles was almost five-fold greater in patients with previous shingles reports. In conclusion, in white adults at CVID/IgGSD diagnosis, age at diagnosis and positivity for HLA-A*01, B*08 have significant positive associations with reports of previous shingles.
    Infectious disease reports 04/2012; 4(2):e34.
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    ABSTRACT: TMPRSS6 A736V is associated with lower transferrin saturation (TS), hemoglobin (Hb), and mean corpuscular volume (MCV) levels in general adult populations. We sought to identify relationships of TMPRSS6 K253E, A736V, and Y739Y to iron, erythrocyte, and pica phenotypes in women with iron deficiency or depletion. We tabulated observations on 48 outpatient non-pregnant women who had iron deficiency (serum ferritin (SF) <14pmol/L and TS <10%) or iron depletion (SF<112pmol/L). We performed direct sequencing of TMPRSS6 exons 7 and 17 in each patient. We used age, TS, SF, Hb, MCV, pica, and TMPRSS6 allele positivity (dichotomous) or mutation genotypes (trichotomous) as variables for analyses. Forty-six women were white; two were black. 58.3% had iron deficiency. 45.8% had pica (pagophagia, each case). Allele frequencies were 41.7% (K253E), 36.5% (A736V), and 39.6% (Y739Y). K253E frequency was greater in women with TS ≥10% (p=0.0001). Y739Y was more frequent in women with TS <10% (p=0.0135). Mean TS was also lower in women positive for Y739Y (6±4% vs. 13±16%, respectively; p=0.0021). In multiple regressions, neither K253E, A736V, nor Y739Y genotypes were significantly associated with other variables. TMPRSS6 K253E frequency was greater in women with TS ≥10%. Frequency of Y739 was greater in women with TS <10%. Mean TS was lower in women with Y739Y. We observed no other significant relationship of TMPRSS6 K253E, A736V, or Y739Y with iron, erythrocyte, or pica phenotypes.
    Blood Cells Molecules and Diseases 02/2012; 48(2):124-7. · 2.26 Impact Factor
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    ABSTRACT: We investigated the risk of death from iron overload among treated hemochromatosis probands who were homozygous for HFE C282Y and had serum levels of ferritin greater than 1000 μg/L at diagnosis. We compared serum levels of ferritin at diagnosis and other conditions with the rate of iron overload-associated death using data from 2 cohorts of probands with hemochromatosis who were homozygous for HFE C282Y (an Alabama cohort, n = 294, 63.9% men and an Ontario cohort, n = 128, 68.8% men). We defined iron overload-associated causes of death as cirrhosis (including hepatic failure and primary liver cancer) caused by iron deposition and cardiomyopathy caused by myocardial siderosis. All probands received phlebotomy and other appropriate therapy. The mean survival times after diagnosis were 13.2 ± 7.3 y and 12.5 ± 8.3 y in Alabama and Ontario probands, respectively. Serum levels of ferritin greater than 1000 μg/L at diagnosis were observed in 30.1% and 47.7% of Alabama and Ontario probands, respectively. In logistic regressions of serum ferritin greater than 1000 μg/L, there were significant positive associations with male sex and cirrhosis in Alabama probands and with age, male sex, increased levels of alanine and aspartate aminotransferases, and cirrhosis in Ontario probands. Of probands with serum levels of ferritin greater than 1000 μg/L at diagnosis, 17.9% of those from Alabama and 14.8% of those from Ontario died of iron overload. Among probands with serum levels of ferritin greater than 1000 μg/L, the relative risk of iron overload-associated death was 5.4 for the Alabama group (95% confidence interval [CI], 2.2-13.1; P = .0002) and 4.9 for the Ontario group (95% CI, 1.1-22.0; P = .0359). In hemochromatosis probands homozygous for HFE C282Y, serum levels of ferritin greater than 1000 μg/L at diagnosis were positively associated with male sex and cirrhosis. Even with treatment, the relative risk of death from iron overload was 5-fold greater in probands with serum levels of ferritin greater than 1000 μg/L.
    Clinical gastroenterology and hepatology: the official clinical practice journal of the American Gastroenterological Association 01/2012; 10(4):412-6. · 5.64 Impact Factor
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    James C Barton, J Clayborn Barton
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    ABSTRACT: Dupuytren's contracture (DC) and HFE hemochromatosis occur in some of the same at-risk populations and present with similar comorbid conditions. We estimated DC prevalence in two cohorts of white Alabama hemochromatosis probands (294 C282Y homozygotes, 67 C282Y/H63D compound heterozygotes) in a retrospective study. We performed logistic regressions on DC using the following independent variables: age, body mass index, heavy ethanol consumption, serum ferritin, elevated serum AST/ALT, non-alcoholic fatty liver disease, viral hepatitis, cirrhosis, and diabetes. One man and two women with C282Y homozygosity had DC (prevalence 1.02%; 95% CI 0.35%-2.96%). A man with C282Y/H63D had DC (prevalence 1.49%; 95% CI 0.26%-7.98%). DC occurred as an autosomal dominant trait in his kinship. In regression analyses, no single variable predicted DC. We observed no new DC cases after the diagnosis of hemochromatosis (mean follow-up 12.9 ± 7.5 years (1 SD), and 9.0 ± 5.1 years, respectively). Our prevalence estimates of DC in white Alabama hemochromatosis probands are similar to those found in the white US population cohorts. DC risk was unrelated to the variables we studied.
    Clinical medicine insights. Arthritis and musculoskeletal disorders. 01/2012; 5:67-75.
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    ABSTRACT: Acute kidney injury (AKI) is a rare complication of carcinoid syndrome. A 61-year-old man developed carcinoid syndrome 51 months after pneumonectomy for bronchial carcinoid, and 8 episodes of AKI 101 to 118 months after pneumonectomy. Serum chromogranin A and urine 5-hydroxyindoleacetic acid levels were elevated for more than 1 year before AKI occurred. Each episode was characterized by flushing, facial edema, mild diarrhea, necrosis of hepatic metastatic nodules, mild oliguria, hyponatremia, acidosis, hypokalemia, hypomagnesemia and hyperphosphatemia. He did not have elevated urine sodium levels or osmolality, hypotension or hypertension. Plasma levels of dopamine, epinephrine and norepinephrine, measured during a single episode, were markedly elevated. Serum creatinine levels returned to normal after most episodes. Hyponatremia persisted but was more severe during AKI. Elevated plasma levels of vasoactive substances other than 5-hydroxytryptamine, perhaps dopamine or other catecholamines, could explain recurrent AKI. The natriuretic effect of elevated plasma dopamine levels could explain chronic hyponatremia.
    The American Journal of the Medical Sciences 01/2012; 343(1):106-8. · 1.33 Impact Factor
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    ABSTRACT: Hemochromatosis is considered by many to be an uncommon disorder, although the prevalence of HFE (High Iron) 282 Cys → Tyr (C282Y) homozygosity is relatively high in Caucasians. Liver disease is one of the most consistent findings in advanced iron overload resulting from hemochromatosis. Liver clinics are often thought to be ideal venues for diagnosis of hemochromatosis, but diagnosis rates are often low. The Hemochromatosis and Iron Overload Screening (HEIRS) Study screened 99,711 primary care participants in North America for iron overload using serum ferritin and transferrin saturation measurements and HFE genotyping. In this HEIRS substudy, serum hepatic transaminases activities (e.g., alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) were compared between 162 C282Y homozygotes and 1,367 nonhomozygotes with serum ferritin levels >300 μg/L in men and >200 μg/L in women and transferrin saturation >45% in women and 50% in men. The probability of being a C282Y homozygote was determined for AST and ALT ranges. Mean ALT and AST activities were significantly lower in C282Y homozygotes than nonhomozygotes. The probability of being a C282Y homozygote increased as the ALT and AST activities decreased. CONCLUSION: Patients with hyperferritinemia are more likely to be C282Y homozygotes if they have normal liver transaminase activities. This paradox could explain the low yields of hemochromatosis screening reported by some liver clinics.
    Hepatology 12/2011; 55(6):1722-6. · 12.00 Impact Factor
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    ABSTRACT: The association of an IgM-Fc receptor (FcμR) with chronic lymphocytic leukemia (CLL) was suggested more than 30 years ago, but its authenticity has never been formally addressed. We examined the expression of the recently identified FcμR by B and T cells in CLL patients using receptor-specific monoclonal antibodies. CLL B cells (CD5(+)/CD19(+)) expressed much higher levels of FcμR on their cell surface than B cells from healthy donors. Such enhanced expression was more evident in immunoglobulin heavy chain variable region (IGHV)-mutated, CD38(-) or early Rai-stage CLL than in IGHV-unmutated, CD38(+), or advanced Rai-stage CLL. Intriguingly, surface FcμR levels also were significantly elevated in the non-CLL B cells (CD5(-)/CD19(+)) and T cells (CD5(+)/CD19(-)), especially in IGHV-mutated CLL. CLL patients also had high serum titers of FcμR compared with healthy donors, and serum FcμR levels correlated significantly with circulating lymphocyte numbers but not with the IGHV mutation status or Rai stage. The serum FcμR was resolved as an ∼ 40-kDa protein, distinct from the cell surface FcμR of ∼ 60 kDa, and it was produced by both CLL B and non-CLL B cells. Mass spectrometric analysis revealed that the serum FcμR is a soluble form of the receptor encoded by an alternatively spliced FcμR transcript. These findings indicate enhanced levels of both membrane-bound and soluble forms of FcμR in CLL patients.
    Blood 09/2011; 118(18):4902-9. · 9.78 Impact Factor
  • American Journal of Hematology 09/2011; 86(9):787-9. · 4.00 Impact Factor
  • James C Barton, J Clayborn Barton
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    ABSTRACT: No abstract available.
    Acta Haematologica 06/2011; 126(3):138-40. · 0.89 Impact Factor
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    Paul C Adams, James C Barton
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    ABSTRACT: Elevated serum ferritin concentrations are common in clinical practice. In this review, we provide an approach to interpreting the serum ferritin elevation in relationship to other clinical parameters including the patient history, transferrin saturation, serum concentrations of alanine, and aspartate aminotransferases (ALT, AST), testing for HFE mutations, liver imaging, liver biopsy, and liver iron concentration. We used observations from a large series of patients with hepatic iron overload documented by liver iron concentration measurement from two referral practices as a gold standard to guide the interpretation of the predictive values of non-invasive iron tests. Three case studies illustrate common problems in interpreting iron blood tests.
    Journal of Hepatology 02/2011; 55(2):453-8. · 9.86 Impact Factor
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    ABSTRACT: Human leukocyte antigen (HLA) haplotypes may influence iron phenotypes in patients with HFE hemochromatosis and could affect survival. We tabulated general characteristics of HLA-A and -B types and haplotypes of HFE C282Y/C282Y probands diagnosed in medical care and analyzed these data to identify HLA survival modifiers. There were 212 probands (130 men, 82 women). Mean follow-up was 12.0 ± 6.4 yr (0.1-41.2 yr; 34 deaths). HLA-A*03 was more prevalent in men (76.9% vs. 61.0% women; P = 0.0129); 35.4% of men and 29.3% of women had A*03, B*07; and 7.7% of men and 8.5% of women had A*03, B*14. Twenty-three probands had cirrhosis; none had A*03, B*14. Positivity for A*03 or A*03, B*07 was not a significant predictor or modifier of survival. In multiple regression analyses, A*03, B*14 predicted longer survival (P = 0.0004). Kaplan-Meier analysis confirmed longer survival in probands with A*03, B*14 (P = 0.0199, log-rank test). After excluding the 23 non-A*03, B*14 probands with cirrhosis, survival of probands with A*03, B*14 was still greater than that of probands without A*03, B*14 (P = 0.0254; log-rank test). Twenty-four years after diagnosis, cumulative survival of probands with and without A*03, B*14 was 100% and 58%, respectively. The percentage of deaths due to iron overload was lower in probands with A*03, B*14 (0% vs. 21.9%; P = 0.0392). In hemochromatosis probands with HFE C282Y/C282Y, survival was longer in those with HLA-A*03, B*14. Earlier age at diagnosis and less severe iron overload in probands with A*03, B*14 could explain this difference.
    European Journal Of Haematology 11/2010; 85(5):439-47. · 2.55 Impact Factor
  • James C Barton, Paul C Adams
    Nature Reviews Gastroenterology &#38 Hepatology 09/2010; 7(9):482-4. · 10.43 Impact Factor
  • Paul C Adams, James C Barton
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    ABSTRACT: Hemochromatosis is a common genetic disorder in which iron may progressively accumulate in the liver, heart, and other organs. The primary goal of therapy is iron depletion to normalize body iron stores and to prevent or decrease organ dysfunction. The primary therapy to normalize iron stores is phlebotomy. In this opinion article, we discuss the indications for and monitoring of phlebotomy therapy to achieve iron depletion, maintenance therapy, dietary and pharmacologic maneuvers that could reduce iron absorption, and the role of voluntary blood donation.
    Blood 03/2010; 116(3):317-25. · 9.78 Impact Factor

Publication Stats

3k Citations
900.36 Total Impact Points

Institutions

  • 1978–2013
    • University of Alabama at Birmingham
      • • Department of Medicine
      • • Department of Microbiology
      • • Department of Psychology
      • • Division of Hematology / Oncology
      Birmingham, AL, United States
  • 2004–2012
    • The Scripps Research Institute
      • Department of Molecular and Experimental Medicine
      La Jolla, CA, United States
    • Rochester General Hospital
      Rochester, New York, United States
  • 2009–2011
    • London Health Sciences Centre
      • • Division of Gastroenterology
      • • Department of Medicine
      London, Ontario, Canada
    • Baylor College of Medicine
      • Department of Medicine
      Houston, TX, United States
    • University of Minnesota Twin Cities
      • Department of Laboratory Medicine and Pathology
      Minneapolis, MN, United States
  • 2007–2011
    • The University of Western Ontario
      • Department of Medicine
      London, Ontario, Canada
    • Kaiser Permanente
      Oakland, California, United States
  • 2008
    • VA Long Beach Healthcare System
      Long Beach, California, United States
    • Howard University
      • Department of Medicine
      Washington, West Virginia, United States
    • Brookdale University Hospital
      • Department of Medicine
      Brooklyn, NY, United States
  • 2006
    • University of California, Irvine
      • Department of Medicine
      Irvine, CA, United States
  • 2000
    • Saint Louis University
      Saint Louis, Michigan, United States
  • 1987–1988
    • University of Texas Health Science Center at San Antonio
      • Department of Pediatrics
      San Antonio, TX, United States