Turner syndrome (TS) is an interesting model for investigating the association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and non-disjunction because of the high frequency of chromosomal mosaicism among patients with this syndrome. We determined the frequencies of MTHFR 677C -> T and 1298A -> C polymorphic mutations in 49 patients with TS and 200 control individuals. The frequency of the 677C -> T allele was 0.39 for patients and 0.29 for controls while that of the 1298A -> C allele was 0.28 for patients and 0.25 for controls. Genotype frequencies were shown to be different in patients and controls (chi2 = 12.143; p = 0.033), and this was attributable to the higher frequency of the C677C -> T /677C -> T genotype among TS patients. In homozygotes, this mutation might have an effect on somatic chromosome disjunction by decreasing MTHFR activity.

A síndrome de Turner (ST) caracteriza-se pela perda parcial ou total de um dos cromossomos X, hipogonadismo hipergonadotrófico e baixa estatura. A maioria dos estudos de densidade mineral óssea (DMO) em ST atribuem a osteoporose à ausência do desenvolvimento puberal e ao hipoestrogenismo, enquanto o envolvimento das alterações ósseas intrínsecas à ST permanece obscuro. O objetivo deste estudo foi verificar a associação entre a DMO com as variáveis como idade cronológica e óssea, peso, altura, cariótipo, doenças associadas e reposição estrogênica em pacientes com ST. Realizou-se um estudo transversal da DMO areal de L2-L4 por DEXA em 34 pacientes com diagnóstico citogenético de ST. Encontrou-se diferença estatística em relação à idade (as pacientes com z DMO < -2,5 eram as de idade mais avançada), à altura (as pacientes com z DMO < -2,5 eram as mais altas) e a reposição estrogênica (o z DMO foi menor nas pacientes que necessitaram de reposição hormonal). Sugere-se, portanto, que a idade e a reposição estrogênica podem ser fatores associados à baixa DMO na ST.

Total or partial X chromosome loss, hypergonadotrophic hypogonadism and short stature characterize Turner syndrome (TS). Delayed puberty and hypoestrogenism are the determinant factors of osteoporosis in TS, and the compromise of intrinsic bone defect is yet obscure. The aim of this study was to evaluate the association between bone mineral density (BMD) and chronological and bone age, weight, height, karyotype, associated diseases, bone age and estrogen therapy in TS patients. We performed a transversal study with areal BMD of L2-L4 with DEXA in 34 patients with cytogenetic diagnosis of TS. Statistical differences were present concerning age and height, since TS patients with z BMD <2.5 were older and taller. The z BMD analysis revealed lower values in patients who needed estrogen therapy. These results suggest that in patients with TS, age and estrogen therapy could be associated with low BMD.

A síndrome de Kallmann (SK) é caracterizada clinicamente pela associação de hipogonadismo hipogonadotrófico e anosmia ou hiposmia, para a qual três modos de herança foram descritos: ligada ao X, autossômica dominante e recessiva. O gene KAL-1, responsável pela forma da síndrome ligada ao X, foi isolado e sua organização éxon-íntron determinada. Neste estudo, duas famílias com síndrome de Kallmann ligada ao X e quatro indivíduos do sexo masculino com hipogonadismo hipogonadotrófico e anosmia foram citogeneticamente investigados por meio de técnicas de alta-resolução e FISH. A análise citogenética não revelou qualquer rearranjo cromossômico. A deleção do gene KAL-1 foi detectada por FISH em apenas um caso esporádico, em um paciente com sinais característicos de SK e palato alto. Entre os casos familiais foram observadas anomalias renais e pes cavus.

Kallmann syndrome (KS) is a disease clinically characterized by the association of hypogonadotropic hypogonadism and anosmia or hyposmia, for which three modes of transmission have been described: X-linked, autosomal recessive and autosomal dominant. The KAL-1 gene, responsible for the X-linked form of the disease, has been isolated and its intron-exon organization determined. In this study, two families with X-linked KS and four sporadic male patients with hypogonadotropic hypogonadism and anosmia were cytogenetically investigated with high-resolution techniques and FISH. Chromosomal analysis did not reveal any rearrangements or deletions. Deletion of the KAL-1 gene was detected by FISH in only one sporadic patient, with the typical features of KS and a high palate. Among the familial cases renal abnormalities and pes cavus deformity were observed.