Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0235394 (wasting)
 8,040 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pseudohypoaldosteronism type 1 (PHA1, OMIM 264350) is an uncommon inherited disorder characterized by salt-wasting and end-organ unresponsiveness to mineralocorticoids. A complete genome search using homozygosity mapping in eleven consanguineous families with PHA1 provided conclusive evidence of linkage with heterogeneity. The disease locus mapped to chromosome 16p12.2-13.11 in six families and to 12p13.1-pter in the other five families. These two chromosomal regions harbour the genes encoding the three subunits of the human amiloride sensitive epithelial sodium channel (hENaC): SCNN1B and SCNN1G on 16p and SCNN1A on 12p. Our linkage results have been further supported by the recent report of mutations in the alpha and beta subunit genes in PHA1 patients. We now report the identification of a 3' splice site mutation in SCNN1G (318-1 G-->A) in three families showing linkage to 16p. Abnormal splicing results with the production of two messenger RNAs, one arising from activation of an adjacent cryptic splice site and the other from skipping of the downstream exon. The two corresponding mutant gamma hENaC subunits are predicted to have three highly conserved amino acids in the extracellular domain replaced by a novel amino acid (KYS106-108-->N) and truncation from 649 to 134 amino acids respectively. These three families all originate from the Indian sub-continent and the probands have severe generalized PHA. They share a common haplotype which suggests the presence of a founder mutation in this sub-population.
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PMID:A novel splice-site mutation in the gamma subunit of the epithelial sodium channel gene in three pseudohypoaldosteronism type 1 families. 864 Feb 38

Pseudohypoaldosteronism type I (PHA1) is characterized by neonatal renal salt wasting with dehydration, hypotension, hyperkalaemia and metabolic acidosis, despite elevated aldosterone levels. Two forms of PHA1 exist. An autosomal recessive form features severe disease with manifestations persisting into adulthood. This form is caused by loss-of-function mutations in genes encoding subunits of the amiloride-sensitive epithelial sodium channel (ENaC; refs 2,3). Autosomal dominant or sporadic PHA1 is a milder disease that remits with age. Among six dominant and seven sporadic PHA1 kindreds, we have found no ENaC gene mutations, implicating mutations in other genes. As ENaC activity in the kidney is regulated by the steroid hormone aldosterone acting through the mineralocorticoid receptor, we have screened the mineralocorticoid receptor gene (MLR) for variants and have identified heterozygous mutations in one sporadic and four dominant kindreds. These include two frameshift mutations (one a de novo mutation), two premature termination codons and one splice donor mutation. These mutations segregate with PHA1 and are not found in unaffected subjects. These findings demonstrate that heterozygous MLR mutations cause PHA1, underscore the important role of mineralocorticoid receptor function in regulation of salt and blood pressure homeostasis in humans and motivate further study of this gene for a potential role in blood pressure variation.
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PMID:Mutations in the mineralocorticoid receptor gene cause autosomal dominant pseudohypoaldosteronism type I. 966 4

Pseudohypoaldosteronism (PHA) type 1 presents in infancy with potential life-threatening salt wasting and failure to thrive. Plasma renin activity and aldosterone levels are markedly elevated. PHA1 is inherited in either an autosomal recessive or autosomal dominant trait. The autosomal dominant form manifests with renal salt loss in infancy and a gradual improvement with advancing age. We report the case of a renal form of PHA1 in a German family. PCR and direct sequencing revealed a heterozygous point mutation, c488C>G (S163X), leading to a premature stop codon in the index patient. The segregation analysis revealed the identical mutation in the patient's father, who showed no symptoms of PHA at the time of investigation or before. The family was screened for amino acid polymorphisms in the amiloride-sensitive epithelial sodium channel, which could be a cause for phenotypic differences within the family. PCR and direct sequencing revealed identical epithelial sodium channel haplotypes in the patient and his father. These polymorphisms can, therefore, not be responsible for the difference in clinical presentation. It remains to be elucidated whether other defects or polymorphisms in genes coding for regulatory proteins participating in sodium homeostasis are a cause of the heterogeneity of the clinical manifestations in autosomal dominant PHA1.
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PMID:Identification of a novel mutation in the human mineralocorticoid receptor gene in a german family with autosomal-dominant pseudohypoaldosteronism type 1: further evidence for marked interindividual clinical heterogeneity. 1267 57

We have analyzed the human mineralocorticoid receptor (hMR) gene in 14 families with autosomal dominant or sporadic pseudohypoaldosteronism (PHA1), a rare form of mineralocorticoid resistance characterized by neonatal renal salt wasting and failure to thrive. Six heterozygous mutations were detected. Two frameshift mutations in exon 2 (insT1354, del8bp537) and one nonsense mutation in exon 4 (C2157A, Cys645stop) generate truncated proteins due to premature stop codons. Three missense mutations (G633R, Q776R, L979P) differently affect hMR function. The DNA binding domain mutant R633 exhibits reduced maximal transactivation, although its binding characteristics and ED(50) of transactivation are comparable with wild-type hMR. Ligand binding domain mutants R776 and P979 present reduced or absent aldosterone binding, respectively, which is associated with reduced or absent ligand-dependent transactivation capacity. Finally, P979 possesses a transdominant negative effect on wild-type hMR activity, whereas mutations G633R and Q776R probably result in haploinsufficiency in PHA1 patients. We conclude that hMR mutations are a common feature of autosomal dominant PHA1, being found in 70% of our familial cases. Their absence in some families underscores the importance of an extensive investigation of the hMR gene and the role of precise diagnostic procedures to allow for identification of other genes potentially involved in the disease.
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PMID:Different inactivating mutations of the mineralocorticoid receptor in fourteen families affected by type I pseudohypoaldosteronism. 1278 47

Pseudohypoaldosteronism type I (PHA1) is a condition associated with salt wasting leading to dehydration, hypotension, hyperkalemia, and metabolic acidosis. Sporadic cases and two familial forms, one autosomal dominant and one autosomal recessive form, have been described. The autosomal dominant or sporadic form manifests milder salt wasting that remits with age. Mutations in the gene encoding the mineralocorticoid receptor (MR) have been identified in patients with the autosomal dominant inheritance. However, recent studies suggest that the autosomal dominant and sporadic forms are genetically heterogeneous and that additional genes might be involved. We report on the study of 15 members of a Swedish five-generation family with the autosomal dominant form of PHA1. Interestingly, neuropathy was found in two of five affected individuals. A novel heterozygous nonsense mutation C436X in exon 2 was identified in the index patient by linkage analysis, PCR, and direct sequencing of the MR gene. Analysis of the family demonstrated that the mutation segregated with PHA1 in the family. It is unclear whether the neuropathy is associated with the mutation found. Our results together with previously published data suggest that loss-of-function mutations of the MR gene located at 4q31.1, commonly are associated with the autosomal dominant form of PHA1.
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PMID:A novel nonsense mutation of the mineralocorticoid receptor gene in a Swedish family with pseudohypoaldosteronism type I (PHA1). 1471 54

Type I pseudohypoaldosteronism (PHA1) is a rare form of mineralocorticoid resistance characterized by neonatal renal salt wasting and failure to thrive. Typical biochemical features include high levels of plasma aldosterone and renin, hyponatremia and hyperkalemia. Different mutations of the human mineralocorticoid receptor (hMR) gene have been identified in subjects affected by the autosomal dominant or sporadic form of the disease. Our laboratory has investigated a large number of subjects with familial and sporadic PHA1. Several different mutations have been detected, which are localized in different coding exons of the hMR gene. These mutations either create truncated proteins, either affect specific amino acids involved in receptor function. In this paper, we review hMR mutations described to date in PHA1 and their functional characterization. We discuss the absence of mutations in some kindreds and the role of precise phenotypic and biological examination of patients to allow for identification of other genes potentially involved in the disease.
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PMID:Inactivating mutations of the mineralocorticoid receptor in Type I pseudohypoaldosteronism. 1513 10

Mineralocorticoid resistance, also known as type I pseudohypoaldosteronism (PHA1), is a rare inherited disease characterized by salt wasting, dehydration and failure to thrive in the newborn. Two different forms of the disease, which present with either systemic or exclusively renal resistance to aldosterone, are associated with two different modes of inheritance. The generalized, recessive form of the disease is due to abnormalities in the epithelial sodium channel, and inactivating mutations of the mineralocorticoid receptor are responsible for the autosomal dominant form of PHA1 and some sporadic cases. Here, we review the role of aldosterone in the maintenance of normal sodium balance and discuss the different forms of mineralocorticoid resistance and the underlying genetic abnormalities. Although important progress has been made in the past years, there remain several families in whom the genetic defect has not been identified. Precise clinical diagnosis and establishment of intermediate phenotypes should be helpful for identifying other genes involved in PHA1 and gaining new insight into the regulation of sodium homeostasis.
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PMID:Mineralocorticoid resistance. 1535 79

Aldosterone plays a key role in electrolyte balance and blood pressure regulation. Type 1 pseudohypoaldosteronism (PHA1) is a primary form of mineralocorticoid resistance characterized in the newborn by salt wasting, hyperkalemia, and failure to thrive. Inactivating mutations of the mineralocorticoid receptor (MR; NR3C2) are responsible for autosomal dominant and some sporadic cases of PHA1. The question as to whether other genes may be involved in the disease is of major importance because of the potential life-threatening character of the disease, the potential cardiovascular effects of compensatory aldosterone excess, and the role of the mineralocorticoid system in human hypertension. We present the first comprehensive study seeking nucleotide substitutions in coding regions, intron-exon junctions, and untranslated exons, as well as for large deletions. A total of 22 MR gene abnormalities were found in 33 patients. We demonstrate that MR mutations are extremely frequent in PHA1 patients classified according to aldosterone and potassium levels and give indications for accurate clinical and biological investigation. In our study the possibility of a genocopy exists in three PHA1 kindreds. The other patients without MR mutations might have different diseases resembling to PHA1 in the neonatal period, which could be identified by extensive clinical and functional exploration.
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PMID:Mineralocorticoid receptor mutations are the principal cause of renal type 1 pseudohypoaldosteronism. 1697 28

Aldosterone plays an essential role in the maintenance of fluid and electrolyte homeostasis in the distal nephron. Loss-of-function mutations in two key components of the aldosterone response, the mineralocorticoid receptor and the epithelial sodium channel ENaC, lead to type 1 pseudohypoaldosteronism (PHA1), a rare genetic disease of aldosterone resistance characterized by salt wasting, dehydration, failure to thrive, hyperkalemia and metabolic acidosis. This review describes the clinical, biological and genetic characteristics of the different forms of PHA1 and highlights recent advances in the understanding of the pathogenesis of the disease. We will also discuss genotype-phenotype correlations and new clinical and genetic entities that may prove relevant for patient's care in neonates with renal salt losing syndromes and/or failure to thrive.
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PMID:Aldosterone resistance: structural and functional considerations and new perspectives. 2166 33

Type I pseudohypoaldosteronism (PHA1) is a rare form of mineralocorticoid resistance presenting in infancy with renal salt wasting and failure to thrive. Here, we present the case of a 6-week-old baby girl who presented with mild hyponatraemia and dehydration with a background of severe failure to thrive. At presentation, urinary sodium was not measurably increased, but plasma aldosterone and renin were increased, and continued to rise during the subsequent week. Despite high calorie feeds the infant weight gain and hyponatraemia did not improve until salt supplements were commenced. Subsequently, the karyotype was reported as 46,XX,inv (4)(q31.2q35). A search of the OMIM database for related genes at or near the inversion breakpoints, showed that the mineralocorticoid receptor gene (NR3C2) at 4q31.23 was a likely candidate. Further FISH analysis showed findings consistent with disruption of the NR3C2 gene by the proximal breakpoint (4q31.23) of the inversion. There was no evidence of deletion or duplication at or near the breakpoint. This is the first report of a structural chromosome disruption of the NR3C2 gene giving rise to the classical clinical manifestations of pseudohypoaldosteronism type 1 in an infant.
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PMID:Structural chromosome disruption of the NR3C2 gene causing pseudohypoaldosteronism type 1 presenting in infancy. 2193 99


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