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- Fava, Cristiano, et al.
(författare)
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Subjects heterozygous for genetic loss of function of the thiazide-sensitive cotransporter have reduced blood pressure
- 2008
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 17:3, s. 413-418
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Tidskriftsartikel (refereegranskat)abstract
- Gitelmans syndrome (GS) is an inherited recessive disorder caused by homozygous or compound heterozygous loss of function mutations of the NaCl cotransporter (NCCT) gene encoding the kidney-expressed NCCT, the pharmacological target of thiazide diuretics. An observational study estimated the prevalence of GS to 19/1 000 000, in Sweden, suggesting that similar to 1% of the population carries one mutant NCCT allele. As the phenotype of GS patients, who always carry two mutant alleles, is indistinguishable from that seen in patients treated with high-dose thiazide diuretics, we aimed at investigating whether subjects carrying one mutated NCCT allele have a phenotype resembling that of treatment with low-dose thiazide diuretics. We screened first-degree relatives of 18 of our patients with an established clinical end genetic diagnosis of GS for NCCT loss of function mutations and identified 35 healthy subjects carrying one mutant allele (GS-heterozygotes). Each GS-heterozygote was assigned a healthy control subject matched for age, BMI and sex. GS-heterozygotes had markedly lower blood pressure (systolic 103.3 +/- 16.4 versus 123.2 +/- 19.4 mmHg; diastolic 62.5 +/- 10.5 versus 73.1 +/- 9.4 mmHg; P < 0.001) than controls. There was no significant difference between the groups either in plasma concentration or urinary excretion rate of electrolytes, however, GS-heterozygotes had higher fasting plasma glucose concentration. Similar to patients being treated with low-dose thiazide diuretics, GS-heterozygotes have markedly lower blood pressure and slightly higher fasting plasma glucose compared with control subjects. Our findings suggest that GS-heterozygotes, the prevalence of which can be estimated to 1%, are partially protected from hypertension through partial genetic loss of function of the NCCT. However, as our study had a case-control design, it is important to underline that any potential effects on population blood pressure and risk of future cardiovascular disease need to be examined in prospective and population-based studies.
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| 2. |
- Silberberg, Gilad, et al.
(författare)
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Deregulation of the A-to-I RNA editing mechanism in psychiatric disorders
- 2012
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 21:2, s. 311-321
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Tidskriftsartikel (refereegranskat)abstract
- Schizophrenia and bipolar disorder (BPD) are common neurodevelopmental disorders, characterized by various life-crippling symptoms and high suicide rates. Multiple studies support a strong genetic involvement in the etiology of these disorders, although patterns of inheritance are variable and complex. Adenosine-to-inosine RNA editing is a cellular mechanism, which has been implicated in mental disorders and suicide. To examine the involvement of altered RNA editing in these disorders, we: (i) quantified the mRNA levels of the adenosine deaminase acting on RNA (ADAR) editing enzymes by real-time quantitative polymerase chain reaction, and (ii) measured the editing levels in transcripts of several neuroreceptors using 454 high-throughput sequencing, in dorsolateral-prefrontal cortices of schizophrenics, BPD patients and controls. Increased expression of specific ADAR2 variants with diminished catalytic activity was observed in schizophrenia. Our results also indicate that the I/V editing site in the glutamate receptor, ionotropic kainate 2 (GRIK2) transcript is under-edited in BPD (type I) patients (45.8 versus 53.9%, P= 0.023). GRIK2 has been implicated in mood disorders, and editing of its I/V site can modulate Ca(+2) permeability of the channel, consistent with numerous observations of elevated intracellular Ca(+2) levels in BPD patients. Our findings may therefore, at least partly, explain a molecular mechanism underlying the disorder. In addition, an intriguing correlation was found between editing events on separate exons of GRIK2. Finally, multiple novel editing sites were detected near previously known sites, albeit most with very low editing rates. This supports the hypothesis raised previously regarding the existence of wide-spread low-level 'background' editing as a mechanism that enhances adaptation and evolvability.
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