1/2. Hypokalemic nephropathy in an adult patient with partial empty sella: a classic Bartter's syndrome, a Gitelman's syndrome or both?Bartter's syndrome belongs to a group of hypokalemic renal channel diseases. These channels are located in the lipid layer of cell membranes where they exist as water channels through which ion transport is performed. Based on the type of genetic disorder and clinical presentation, Bartter's syndrome is classified as neonatal, classical and Gitelman's syndrome. Most of the cases have been noted in pediatric age groups and adult-onset cases are very rare. Moreover, an association between Bartter's syndrome and empty sella has recently been reported in 3 children. We report here the second case of an adult patient affected by Bartter's syndrome with partial empty sella. The patient showed some clinical and histological characteristics of both classic Bartter's syndrome and Gitelman's syndrome, suggesting that genotype and phenotype of Bartter's syndrome are not so clear-cut and that phenotypic overlap may occur, according to a recent hypothesis. magnetic resonance imaging disclosed a partial empty sella. A thorough endocrinological investigation showed normal hypophyseal, thyroidal, adrenal and gonadal function. Good therapeutic effects were achieved using spironolactone, ACE-inhibitor and potassium supplementation, with normalization of the kalemia. At present, the value of the association of Bartter's syndrome and empty sella remains unclear and future studies are needed to clarify the importance of this association, both in children and in adult patients affected by Bartter's syndrome.- - - - - - - - - - ranking = 1keywords = hypokalemic (Clic here for more details about this article) |
2/2. A novel splicing mutation in SLC12A3 associated with gitelman syndrome and idiopathic intracranial hypertension.We report a case of gitelman syndrome (GS) in a dizygotic twin who presented at 12 years of age with growth delay, metabolic alkalosis, hypomagnesemia and hypokalemia with inappropriate kaliuresis, and idiopathic intracranial hypertension with bilateral papilledema (pseudotumor cerebri). The patient, her twin sister, and her mother also presented with cerebral cavernous malformations. Based on the early onset and normocalciuria, bartter syndrome was diagnosed first. However, mutation analysis showed that the proband is a compound heterozygote for 2 mutations in SLC12A3: a substitution of serine by leucine at amino acid position 555 (p.Ser555Leu) and a novel guanine to cytosine transition at the 5' splice site of intron 22 (c.2633 1G>C), providing the molecular diagnosis of GS. These mutations were not detected in 200 normal chromosomes and cosegregated within the family. Analysis of complementary dna showed that the heterozygous nucleotide change c.2633 1G>C caused the appearance of 2 rna molecules, 1 normal transcript and 1 skipping the entire exon 22 (r.2521_2634del). Supplementation with potassium and magnesium improved clinical symptoms and resulted in catch-up growth, but vision remained impaired. Three similar associations of bartter syndrome/GS with pseudotumor cerebri were found in the literature, suggesting that electrolyte abnormalities and secondary aldosteronism may have a role in idiopathic intracranial hypertension. This study provides further evidence for the phenotypical heterogeneity of GS and its association with severe manifestations in children. It also shows the independent segregation of familial cavernomatosis and GS.- - - - - - - - - - ranking = 1.5383927773737keywords = alkalosis (Clic here for more details about this article) |