Family-based association of HLA class II alleles and haplotypes with type I diabetes in Brazilians reveals some characteristics of a highly diversified population

The association of HLA class II haplotypes with type I diabetes was analyzed in 56 Southeastern Brazilian families using affected family-based controls (AFBAC) method. DRB1-DQA1-DQB1 alleles were determined by polymerase chain reaction/sequence-specific primer genotyping. This study first revealed the great haplotype diversity of Brazilians (65 different haplotypes even with incomplete DRB1 subtyping), probably due to the admixture of Africans genes with European and Amerindian genes in this population. The results revealed increased frequencies of the DRB1*03-DQA1*0501-DQB1*02 and DRB1*0401-DQA1*03-DQB1*0302 haplotypes in the patient group The highest risk for type I diabetes was associated with the heterozygote DRB1*03/*04 genotype as largely reported, and DRB1*03/X and DRB1*04/Y genotypes conferred a significant, but much lower disease risk. Protection from type I diabetes revealed some peculiarities in Southeastern Brazilians: a lack of significant protecting effect of the DRB1*1501-DQA1*0102-DQB1*0602 haplotype, and an apparent protection conferred by the DRB1*13-DQB1*0301, DRB1*11-DQB1*0301, and DRB1*01-DQB1*0501 two-locus haplotypes. The risk to type I diabetes in the highly diversified Southeastern Brazilians evidenced specific information to the prediction of the disease in this region of the country.

Turner's syndrome and thyroid disease: a transverse study of pediatric patients in Brazil

An increased prevalence of autoimmune thyroid disease (AITD) has been described in Turner's syndrome (TS), but the extent of this association is still controversial. Some studies also suggest that AITD is more frequent among patients with X-isochromosome. In order to determine the prevalence of AITD among girls with TS, and to look for an association with age and karyotype, we evaluated 71 patients with a mean age of 11.4 years (range 0-19.9). 15.5% (11/71) were hypothyroid, 17 (23.9%) were positive for thyroid peroxidase (TPO) and/or thyroglobulin (Tg) antibodies, and 24 (33.8%) had thyromegaly. No abnormality was observed before 4 years, and the highest frequencies were observed after 16 years. There were no significant differences concerning thyroid findings among patients with a 45,X karyotype, mosaics, and structural rearrangements. Half of the patients (35/71) exhibited one or more abnormalities, which demonstrates the importance of careful evaluation of thyroid function in all girls with TS.

Pre-operative control of arterial hypertension using ketoconazole in pediatric patients with adrenocortical tumors

Adrenocortical tumors are rare in childhood, appearing more frequently in some regions such as South and South-eastern regions of Brazil and India. Common clinical signs include virilization, Cushing's syndrome, feminization and hypertension, either isolated or in association. The aim of this report is to present our experience with the pre-operative use of ketoconazole in children with an adrenocortical tumor to control elevated blood pressure levels non-responsive to the usual treatment. Over the last 16 years, of 46 children diagnosed as having adrenocortical tumor, 17 developed hypertension (diastolic pressure greater than the 95th percentile for age and sex according to data from the Task Force on Blood Pressure Control in Children), associated with virilization and/or Cushing's syndrome. In three of these 17 patients, conventional antihypertensive therapy failed, and they were treated with ketoconazole (200-300 mg/day). This resulted in rapid control of the blood pressure. It is concluded that in selected patients, ketoconazole may be useful adjuvant therapy for the palliative control of the arterial hypertension secondary to adrenocortical tumors, without side effects.

Mutation distribution and CYP21/C4 locus variability in Brazilian families with the classical form of the 21-hydroxylase deficiency

Deficiency of adrenal steroid 21-hydroxylase is the most common form of congenital adrenal hyperplasia and it is considered to be responsible for 90% of the disease. This paper describes for the first time the CYP21B mutation profile in Brazilian patients. We genotyped 41 families with at least one individual affected with the classical form of the 21-hydroxylase deficiency, representing 74 unrelated alleles. In order to characterize different disease-causing alleles, genotyping was performed by Southern blot analysis with three restriction enzymes, allele-specific oligonucleotide hybridization, and allele-specific PCR. Different alleles were distinguished by TaqI C4B RFLP, gene duplications or deletions of either CYP21A + C4B or CYP21B + C4B, large gene conversions and eight mutations that might have been introduced into CYP21B from CYP21A by microconversion events. At least one mutation was detected in 24 different disease-causing alleles, which represents about 85% of the affected alleles in those families. The frequency of the 30 kb deletion of CYP21B was lower than that described for Caucasians. The mutation Sp2 showed the highest frequency (24.65%) and was present mainly in salt-wasting patients, although it was also detected in some patients with the simple virilizing form of the disease. Conversely, I172N showed a frequency of 18.91% and was found mostly in patients affected with the simple virilizing form of the disease. Five other mutations were determined at low frequency, but CL6 was not found in any of the tested alleles.

True hermaphrodites in the southeastern region of Brazil: a different cytogenetic and gonadal profile

Sex ambiguity may be due to several disorders of gonadal differentiation, including true hermaphroditism (TH), as well as male and female pseudohermaphroditism. Although TH is a rare cause of intersex in Europe and North America, in Africa it presents one of the highest frequencies. The 46,XX karyotype has been found in the majority of the reported patients (70.6%), and aberrations in the sex chromosomes have been observed in about 22% of the cases. The 46,XY karyotype has been described as less frequent. Herein we describe ten cases of TH which have been diagnosed over the last 7 years, six lateral TH, two unilateral TH, and two cases of ovotestes with absent contralateral gonad. From a total of 18 gonads analyzed, there were 8 testes, 6 ovaries and 4 ovotestes. Nine subjects had originally a male sex assignment, and in three cases this was reverted to female. Four cases had a 46,XY karyotype. Additional sex chromosome aberrations had been found in four different cases [two 46,XX/46,XY, one 45,X/47,XYY, one 46,X,del(Yq)]. A 46,XX karyotype was found in only two individuals, and both were SRY negative. Our preliminary data, especially on the constitution of chromosomes and gonads, indicate marked differences from those in the literature.

Female pseudohermaphroditism due to classical 21-hydroxylase deficiency in a girl with Turner syndrome

We report on a rare case of female pseudohermaphroditism due to classical 21-hydroxylase deficiency associated with Turner syndrome (45,X/46,XX). Difficulties in the management of both diseases are briefly discussed. We regard this rare combination as a coincidental occurrence.