Novel deletion alleles carrying CYP21A1P/A2 chimeric genes in Brazilian patients with 21-hydroxylase deficiency.

BACKGROUND: Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is caused by deletions, large gene conversions or mutations in CYP21A2 gene. The human gene is located at 6p21.3 within a locus containing the genes for putative serine/threonine Kinase RP, complement C4, steroid 21-hydroxylase CYP21 tenascin TNX, normally, in a duplicated cluster known as RCCX module. The CYP21 extra copy is a pseudogene (CYP21A1P). In Brazil, 30-kb deletion forming monomodular alleles that carry chimeric CYP21A1P/A2 genes corresponds to ~9% of disease-causing alleles. Such alleles are considered to result from unequal crossovers within the bimodular C4/CYP21 locus. Depending on the localization of recombination breakpoint, different alleles can be generated conferring the locus high degree of allelic variability. The purpose of the study was to investigate the variability of deleted alleles in patients with 21-hydroxylase deficiency. METHODS: We used different techniques to investigate the variability of 30-kb deletion alleles in patients with 21-hydroxylase deficiency. Alleles were first selected after Southern blotting. The composition of CYP21A1P/A2 chimeric genes was investigated by ASO-PCR and MLPA analyses followed by sequencing to refine the location of recombination breakpoints. Twenty patients carrying at least one allele with C4/CYP21 30-kb deletion were included in the study. RESULTS: An allele carrying a CYP21A1P/A2 chimeric gene was found unusually associated to a C4B/C4A Taq I 6.4-kb fragment, generally associated to C4B and CYP21A1P deletions. A novel haplotype bearing both p.P34L and p.H62L, novel and rare mutations, respectively, was identified in exon 1, however p.P30L, the most frequent pseudogene-derived mutation in this exon, was absent. Four unrelated patients showed this haplotype. Absence of p.P34L in CYP21A1P of normal controls indicated that it is not derived from pseudogene. In addition, the combination of different approaches revealed nine haplotypes for deleted 21-hydroxylase deficiency alleles. CONCLUSIONS: This study demonstrated high allelic variability for 30-kb deletion in patients with 21-hydroxylase deficiency indicating that a founder effect might be improbable for most monomodular alleles carrying CYP21A1P/A2 chimeric genes in Brazil.

Turner's syndrome and subclinical autoimmune thyroid disease: a two-year follow-up study.

Although autoimmune thyroid disease (AITD) is frequent in Turner's syndrome (TS), followup studies are scant, and there are none regarding subclinical thyroiditis. We investigated thyroid function and morphology in 17 patients with TS (mean age 14.6 years) with transient and asymptomatic variations of TSH and/or thyroid hormones. Our 2-year follow-up included measurements of TSH, free T4, T3 and TPO and Tg antibodies, ultrasound (US) (first and last evaluations) and scintigraphy (first evaluation). Thyroid volume was evaluated relative to the patients' stature. Fourteen had abnormal hormones, including four with hypothyroidism and one with hyperthyroidism, ten had positive antibodies, and all had abnormalities on US; uptake was normal in 14/16. Abnormal hormones were independent of antibodies, number of US findings, age, time of disease and volume. At the end of the follow-up, antibodies were associated with a high number of abnormal US features, particularly heterogeneous texture. Our results indicate that recurring thyroid hormone variations in TS are due to chronic AITD.

[Growth and body composition in children with type 1 diabetes mellitus]. / Crescimento e composição corporal de crianças com diabetes mellitus tipo 1.

OBJECTIVE: To evaluate the growth and body composition of pre-pubertal diabetic children, and to check for influence of the age of diabetes onset and length, sex, insulin requirement and glycosylated hemoglobin. PATIENTS AND METHODS: 59 diabetic children (39 M; 29 F), age 1.2-11.5 years, and 67 controls (36 M; 31 F), age 1.2-11.7 years were included. Weight, height, body mass index (BMI), arm circumference, skin folds, fat mass and muscle areas were evaluated and transformed into standard deviation scores (SDS). RESULTS: Among the diabetic children the mean height SDS was -0.13 (+/- 0.97) while in the control group it was 0.28 (+/- 0.86) (p= 0.013). The difference between the first and the current height SDS showed that the height SDS decreased significantly (p< 0.001) and multiple regression analysis indicated correlation with the duration of the disease. The mean arm fat SDS also revealed difference (p< 0.001). The means for weight, BMI, addition of 3 skinfolds and muscle mass did not demonstrate difference between the groups. CONCLUSIONS: The diabetic children showed reduction of height SDS during the period studied and they were significantly shorter than the controls, even though their statures were within the population standards. The arm fat area also showed an increase in relation with the controls.