The population of the province of Newfoundland and Labrador is genetically isolated. This isolation is evidenced by an overabundance of several monogenic disorders. The Newfoundland population, like that of other isolates, is now the focus of interest for identification of genes implicated in common diseases. However, the utility of such populations for this purpose remains unproven. In this paper, we review the current genetic architecture of the province, with respect to geographic isolation, homogeneity, founder effect, genetic drift and extended linkage disequilibrium. Based on these factors, we propose that the population of Newfoundland offers many advantages for genetic mapping of common diseases, compared with admixed populations, and even compared with other isolates.
OBJECTIVE -The aim of this study was to determine the incidence of type 1 diabetes among children aged 0 -14 years in the Avalon Peninsula in the Canadian Province of Newfoundland.RESEARCH DESIGN AND METHODS -This was a prospective cohort study of the incidence of childhood type 1 diabetes in children aged 0 -14 years who were diagnosed with type 1 diabetes from 1987 to 2002 on the Avalon Peninsula. Identified case subjects during this time period were ascertained from several sources and verified using the capture-recapture technique. Data were obtained from the only pediatric diabetes treatment center for children living on the Avalon Peninsula.RESULTS -Over the study period, 294 children aged 0 -14 years from the Avalon Peninsula were diagnosed with type 1 diabetes. The incidence of type 1 diabetes in this population over the period 1987-2002 inclusive was 35.93 with a 95% CI of 31.82-40.03. The incidence over this period increased linearly at the rate of 1.25 per 100,000 individuals per year.CONCLUSIONS -The Avalon Peninsula of Newfoundland has one of the highest incidences of type 1 diabetes reported worldwide. The incidence increased over the 16-year study period.
Diabetes Care 27:885-888, 2004T ype 1 diabetes, the most common form of diabetes in childhood, is a T-cell-mediated autoimmune disease in which both genetic and environmental factors play roles in the etiology (1,2). The incidence of childhood type 1 diabetes is known to vary widely between and within countries. The incidence of type 1 diabetes (Յ14 years) varies from 0.1/100,000 per year in China (1990China ( -1994 and Venezuela (1992) to 36.8/ 100,000 per year in Sardinia (1990Sardinia ( -1994) and 36.5/100,000 per year in Finland (1990Finland ( -1994. In most populations the incidence has been increasing (4). The incidence of type 1 diabetes in Canada is available from only a few studies, which were carried out over the past 25 years (3,5-7). Two Canadian provinces have also reported a high incidence of the disease. A 6-year study (1990 -1995) reported a mean incidence of 25.7/ 100,000 in children Ͻ15 years of age who lived in the city of Edmonton (5). A 4-year study from the province of Prince Edward Island reported a mean incidence of 24.5/ 100,000 in children Ͻ15 years of age (1990 -1993) (3). The reported mean incidence for Montreal (1971Montreal ( -1985 among children 0 -14 years was 10.1/ 100,000 (6). The lowest reported incidence was from Toronto (1976Toronto ( -1978 with a mean incidence of 9.0/100,000 per year in children Ͻ19 years of age (7).The study we are reporting was performed at the Janeway Child Health Care Centre (JCHCC), which is the only tertiary care children's hospital servicing the Province of Newfoundland and Labrador. All children with type 1 diabetes who live on the Avalon Peninsula are referred to one of the diabetologists at the JCHCC and are followed from the time of diagnosis by the Janeway Pediatric Diabetes Team. The Avalon Peninsula was chosen for a study of the incidence of diabetes because it is well def...
Background/Aims: Primary adrenal insufficiency (AI) is an important cause of morbidity in children. Our objectives were: (1) to describe the clinical presentation of children with new-onset primary AI, and (2) to identify monogenic causes of primary AI in children. Methods: Chart review and mutation detection in candidate genes were conducted for 11 patients with primary AI. Results: The likely cause of AI was determined in 9 patients. One had a homozygous MC2R mutation associated with familial glucocorticoid deficiency. Two had the same homozygous mutation in the AIRE gene which is associated with type 1 autoimmune polyglandular syndrome. One patient had a heterozygous change in this gene of undetermined significance. Five were homozygous for the previously reported p.R188C STAR mutation causing nonclassic lipoid congenital adrenal hyperplasia, representing the largest cohort of such patients from a single geographic area. In the remaining 2 patients, no clear etiology was identified. Conclusions: We recommend genetic testing for patients who have negative anti-adrenal antibodies or suggestive family history. Diagnosing a genetic etiology can provide information about prognosis and treatment, and is therefore beneficial for patients. Our high proportion of patients with nonclassic lipoid congenital adrenal hyperplasia likely represents a founder effect.
Objectives: The objectives of this study were to establish the prevalence of positive antibodies to endomysium (EMA) and tissue transglutaminase (tTG) in children with type 1 diabetes living in Newfoundland and Labrador (NL), and to examine clinical features associated with positive antibodies. Methods: Patients were recruited from the pediatric diabetes clinic. One hundred sixty-seven children with type 1 diabetes from the 280 children followed at the clinic were prospectively screened for celiac disease using EMA and tTG. The variables of Irish descent, age at onset of diabetes, duration of diabetes, sex, family history of celiac disease, hemoglobin A1C (A1C), ferritin, gastrointestinal symptoms, and body mass index were compiled for all patients. The group of patients with positive antibodies to EMA and/or tTG was compared to the group with negative antibodies. Results: The prevalence of patients with positive antibodies to EMA and/or tTG was 16.8% (n = 28). One patient had also been previously diagnosed with symptomatic celiac disease. The two statistically significant variables with positive antibodies were an earlier age at onset of diabetes (Mann-Whitney U two-tailed test: mean difference 3.2 years, 95% CI 1.7–4.8 years, p < 0.0001) and longer duration of diabetes (Mann-Whitney U two-tailed test: mean difference 2.9 years, 95% CI 1.3–4.4 years, p < 0.0001). Irish descent was associated with positive antibodies but did not reach statistical significance. On logistic regression analysis performed with these three variables together, only age at onset of diabetes remained significant. Conclusions: There is a high prevalence of celiac disease-associated antibodies in children living in NL with type 1 diabetes. Unlike other clinical features, an earlier age at onset of diabetes was predictive for positive antibodies. As the majority of children with positive antibodies did not have signs or symptoms of celiac disease, routine screening for celiac disease in type 1 diabetes is recommended.
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