Aldosterone Synthase Deficiency Type I: Hormonal and Genetic Analyses of Two Cases

1999 ◽  
Vol 52 (6) ◽  
pp. 298-300 ◽  
Author(s):  
Juan P. López-Siguero ◽  
Emilio García-García ◽  
Michael Peter ◽  
Wolfgang G. Sippell
Keyword(s):  
Type I ◽  
Genetic Analyses ◽  
Aldosterone Synthase ◽  
Deficiency Type ◽  
Aldosterone Synthase Deficiency

scholarly journals Hereditary Defect in Biosynthesis of Aldosterone: Aldosterone Synthase Deficiency 1964–19971

1997 ◽  
Vol 82 (11) ◽  
pp. 3525-3528
Author(s):  
Michael Peter ◽  
Lubna Fawaz ◽  
Stenvert L. S. Drop ◽  
Hendrik K. A. Visser ◽  
Wolfgang G. Sippell
Keyword(s):  
Stop Codon ◽  
Molecular Genetic ◽  
Premature Stop Codon ◽  
Type I ◽  
Loss Of Function ◽  
Oxidase Deficiency ◽  
Base Exchange ◽  
Aldosterone Synthase ◽  
Hereditary Defect ◽  
Deficiency Type

We studied two of the three patients with a hereditary defect in the biosynthesis of aldosterone originally described by Visser and Cost in 1964. All three presented as newborns with salt-losing syndrome and failure to thrive. The original biochemical studies showed a defect in the 18-hydroxylation of corticosterone. According to the nomenclature proposed by Ulick, this defect would be termed corticosterone methyl oxidase deficiency type I. We measured plasma steroids in the untreated adult patients and performed molecular genetic studies. Aldosterone and 18-OH-corticosterone were decreased, whereas corticosterone and 11-deoxycorticosterone were elevated, thus confirming the diagnosis of corticosterone methyl oxidase deficiency type I. Cortisol and its precursors were in the normal range. Genetic defects in the gene CYP11B2 encoding aldosterone synthase (P450c11Aldo) have been described in a few cases. We identified a homozygous single base exchange (G to T) in codon 255 (GAG) causing a premature stop codon E255X (TAG). This mutation destroys a Aoc II restriction site. Digestion of a PCR fragment containing exon 4 of CYP11B2 (261 bp) with this restriction enzyme revealed in the two patients homozygous for the E255X mutation only a 261-bp fragment, whereas the heterozygous parents had three fragments (261 bp from the mutant allele and 194 and 67 bp from the wild-type allele). The mutant enzyme had lost the five terminal exons containing the heme binding site, and thus there was a loss of function enzyme. We conclude that the biochemical phenotype of these prismatic cases of congenital hypoaldosteronism can be explained by the patients genotype.

A Mutation in the Protein S Pseudogene Is Linked to Protein S Deficiency in a Thrombophilic Family

1989 ◽  
Vol 62 (03) ◽  
pp. 897-901 ◽  
Author(s):  
Hans K Ploos van Amstel ◽  
Pieter H Reitsma ◽  
Karly Hamulyák ◽  
Christine E M de Die-Smulders ◽  
Pier M Mannucci ◽  
...  
Keyword(s):  
Total Protein ◽  
Protein S ◽  
Southern Analysis ◽  
Type I ◽  
Protein S Deficiency ◽  
S Deficiency ◽  
The Family ◽  
Dna Pattern ◽  
Deficiency Type ◽  
S Genes

SummaryProbands from 15 unrelated families with hereditary protein S deficiency type I, that is having a plasma total protein S concentration fifty percent of normal, were screened for abnormalities in their protein S genes by Southern analysis. Two probands were found to have a deviating DNA pattern with the restriction enzyme Mspl. In the two patients the alteration concerned the disappearance of a Mspl restriction site, CCGG, giving rise to an additional hybridizing Mspl fragment.Analysis of relatives of both probands showed that in one family the mutation does not co-segregate with the phenotype of reduced plasma protein S. In the family of the other proband, however, complete linkage between the mutated gene pattern and the reduced total protein S concentration was found: 12 heterozygous relatives showed the additional Mspl fragment but none of the investigated 26 normal members of the family. The mutation is shown to reside in the PSβ gene, the inactive protein S gene. The cause of type I protein S deficiency, a defect PSα gene has escaped detection by Southern analysis. No recombination has occurred between the PSα gene and the PSβ gene in 23 informative meioses. This suggests that the two protein S genes, located near the centromere of chromosome 3, are within 4 centiMorgan of each other.

Protein S mRNA in Patients with Protein S Deficiency

1995 ◽  
Vol 73 (05) ◽  
pp. 746-749 ◽  
Author(s):  
E Sacchi ◽  
M Pinotti ◽  
G Marchetti ◽  
G Merati ◽  
L Tagliabue ◽  
...  
Keyword(s):  
Gene Polymorphism ◽  
Total Protein ◽  
Restriction Analysis ◽  
Protein S ◽  
Type I ◽  
Protein S Deficiency ◽  
Phenotypic Analysis ◽  
S Deficiency ◽  
Deficiency Type ◽  
S Genes

SummaryA protein S gene polymorphism, detectable by restriction analysis (BstXI) of amplified exonic sequences (exon 15), was studied in seven Italian families with protein S deficiency. In the 17 individuals heterozygous for the polymorphism the study was extended to platelet mRNA through reverse transcription, amplification and densitometric analysis. mRNA produced by the putative defective protein S genes was absent in three families and reduced to a different extent (as expressed by altered allelic ratios) in four families. The allelic ratios helped to distinguish total protein S deficiency (type I) from free protein S deficiency (type IIa) in families with equivocal phenotypes. This study indicates that the study of platelet mRNA, in association with phenotypic analysis based upon protein S assays in plasma, helps to classify patients with protein S deficiency.

Molecular Analysis of the CYP11B2 Gene in 62 Patients with Hypoaldosteronism Due to Aldosterone Synthase Deficiency

2020 ◽  
Vol 106 (1) ◽  
pp. e182-e191
Author(s):  
Christina Merakou ◽  
Irene Fylaktou ◽  
Amalia Sertedaki ◽  
Maria Dracopoulou ◽  
Antonis Voutetakis ◽  
...  
Keyword(s):  
Gene Sequencing ◽  
Failure To Thrive ◽  
In Silico Analysis ◽  
Autosomal Recessive Disorder ◽  
Molecular Study ◽  
Aldosterone Synthase ◽  
Salt Wasting ◽  
Pathogenic Variants ◽  
Novel Variants ◽  
Aldosterone Synthase Deficiency

Abstract Context Isolated congenital hypoaldosteronism presents in early infancy with symptoms including vomiting, severe dehydration, salt wasting, and failure to thrive. The main causes of this rare autosomal recessive disorder is pathogenic variants of the CYP11B2 gene leading to aldosterone synthase deficiency. Objective To investigate the presence of CYP11B2 pathogenic variants in a cohort of patients with a clinical, biochemical, and hormonal profile suggestive of aldosterone synthase deficiency. Design Clinical and molecular study. Setting Tertiary academic Children’s Hospital, Center for Rare Pediatric Endocrine Diseases. Patients and Methods Sixty-two patients (56 unrelated patients and 6 siblings), with hypoaldosteronism and their parents, underwent CYP11B2 gene sequencing after its selective amplification against the highly homologous CYP11B1 gene. In silico analysis of the identified novel variants was carried out to evaluate protein stability and potential pathogenicity. Results CYP11B2 gene sequencing revealed that 62 patients carried a total of 12 different pathogenic CYP11B2 gene variants, 6 of which are novel. Importantly, 96% of the 56 patients carried the previously reported p.T185I variant either in homozygosity or in compound heterozygosity with another variant. The 6 novel variants detected were: p.M1I, p.V129M, p.R141Q, p.A165T, p.R448C, and the donor splice site variant of intron 8, c.1398 + 1G > A. Conclusion Molecular diagnosis was achieved in 62 patients with aldosterone synthase deficiency, the largest cohort thus far reported. Six novel genetic variants were identified as possibly pathogenic, extending the spectrum of reported molecular defects of the CYP11B2 gene.

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