Dataset Information

Detection of Small CYP11B1 Deletions and One Founder Chimeric CYP11B2/CYP11B1 Gene in 11β-Hydroxylase Deficiency.

ABSTRACT:

Objective

11β-Hydroxylase deficiency (11β-OHD) caused by mutations in the CYP11B1 gene is the second most common form of congenital adrenal hyperplasia. Both point mutations and genomic rearrangements of CYP11B1 are important causes of 11β-OHD. However, the high degree of sequence identity between CYP11B1 and its homologous gene CYP11B2, presents unique challenges for molecular diagnosis of suspected 11β-OHD. The aim of this study was to detect the point mutation, indel, small deletion of CYP11B1 and chimeric CYP11B2/CYP11B1 gene in a one-tube test, improving the genetic diagnosis of 11β-OHD.

Methods

Optimized custom-designed target sequencing strategy was performed in three patients with suspected 11β-OHD, in which both the coverage depth of paired-end reads and the breakpoint information of split reads from sequencing data were analysed in order to detect genomic rearrangements covering CYP11B1. Long-range PCR was peformed to validate the speculated CYP11B1 rearrangements with the breakpoint-specifc primers.

Results

Using the optimized target sequencing approach, we detected two intragenic/intergenic deletions of CYP11B1 and one chimeric CYP11B2/CYP11B1 gene from three suspected patients with 11β-OHD besides three pathogenic heterozygous point mutation/indels. Furthermore, we mapped the precise breakpoint of this chimeric CYP11B2/CYP11B1 gene located on chr8:143994517 (hg19) and confirmed it as a founder rearrangement event in the Chinese population.

Conclusions

Our optimized target sequencing approach improved the genetic diagnosis of 11β-OHD.

SUBMITTER: Xie H

PROVIDER: S-EPMC9171383 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature

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Publications

Detection of Small CYP11B1 Deletions and One Founder Chimeric CYP11B2/CYP11B1 Gene in 11β-Hydroxylase Deficiency.

Xie Hua H Yin Hui H Ye Xue X Liu Ying Y Liu Na N Zhang Yu Y Chen Xiaoli X Chen Xiaobo X

Frontiers in endocrinology 20220524

<h4>Objective</h4>11β-Hydroxylase deficiency (11β-OHD) caused by mutations in the CYP11B1 gene is the second most common form of congenital adrenal hyperplasia. Both point mutations and genomic rearrangements of CYP11B1 are important causes of 11β-OHD. However, the high degree of sequence identity between CYP11B1 and its homologous gene CYP11B2, presents unique challenges for molecular diagnosis of suspected 11β-OHD. The aim of this study was to detect the point mutat ...[more]

PMID: 35685215

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Project description:BackgroundCongenital adrenal hyperplasia (CAH) due to steroid 11β-hydroxylase deficiency (11β-OHD) is a rare form of CAH associated with low renin hypertension, hypokalemia, hyperandrogenemia and ambiguous genitalia in affected females. Herein we describe the clinical, hormonal and molecular characteristics of two Uzbekistan siblings with 11β-OHD and analyze the effects of a splicing mutation.Case presentationA 46,XX girl presented with genital ambiguity and low renin hypertension; her 46,XY brother presented with precocious puberty. Hormonal studies suggested 11β-OHD. Mutation analysis was performed by PCR followed by Sanger sequencing of the entire coding regions and their flanking introns of the CYP11B1 gene. Mutation analysis showed that both patients were compound heterozygous for IVS7 + 1G > A, and c.421C > T. Although the identified mutations have been previously described, this is, to our knowledge, the first report of these mutations in compound heterozygotes. A minigene assay was used to determine the effects of the splicing mutation. The constructs containing either the wild-type or the splice-site mutant CYP11B1 genomic DNA of exons-introns 6-9 were transfected into COS-7 cells; subsequently, RNA splicing was assessed by reversed transcribed-PCR of CYP11B1 complementary DNA. The minigene assay revealed that the IVS7 + 1G > A mutation resulted in two shorter incorrectly spliced products; one skipping the exon 7 and the other skipping the exons 7-8. The c.421C > T mutation leads to the introduction of a premature stop codon at residue 141 (p.R141X). These mutations are expected to code non-functional proteins.ConclusionCompound heterozygous mutations (IVS7 + 1G > A and p.R141X) in the CYP11B1 gene were found to cause 11β-OHD. The IVS7 + 1G > A mutation causes aberrant splicing of CYP11B1 leading to exon skipping. This finding could facilitate the future novel therapies targeted on splicing modulation to treat human disease.

Project description:Unlabelled11β-hydroxylase deficiency (11β-OHD), an autosomal recessive inherited disorder, accounts for 5-8% of congenital adrenal hyperplasia. In Greece, no cases of 11β-OHD have been described so far. The patient presented at the age of 13 months with mild virilization of external genitalia and pubic hair development since the age of 3 months. Hormonal profile showed elevated 11-deoxycortisol, adrenal androgens and ACTH levels. ACTH stimulation test was compatible with 11β-OHD. DNA of the proband and her parents was isolated and genotyped for CYP11B1 gene coding cytochrome P450c11. The girl was found to be compound heterozygous for two CYP11B1 novel mutations, p.Ala386Glu (exon 7), inherited from the father and p.Leu471Argin (exon 9) from the mother. Hydrocortisone supplementation therapy was initiated. Four years after presentation she remains normotensive, her growth pattern is normal and the bone age remains advanced despite adequate suppression of adrenal androgens.Learning points11β-hydroxylase (CYP11B1) deficiency (11OHD; OMIM +202010) is the second most common cause of CAH accounting for approximately 5-8% of cases with an incidence of 1:100 000-1:200 000 live births in non-consanguineous populations.Two CYP11B1 inactivating novel mutations, p.Ala386Glu and p.Leu471Arg are reportedRegarding newborn females, in utero androgen excess results in ambiguous genitalia, whereas in the male newborn diagnosis may go undetected. In infancy and childhood adrenal androgen overproduction results in peripheral precocious puberty in boys and various degrees of virilization in girls.Accumulation of 11-deoxycorticosterone and its metabolites causes hypertension in about two thirds of patients.Diagnosis lies upon elevated 11-deoxycortisol and DOC plus upstream precursors, such as 17α-hydroxyprogesterone and Δ4-androstenedione.The established treatment of steroid 11β-OHD is similar to that of steroid 21-hydroxylase deficiency and consists of glucocorticoid administration in order to reduce ACTH-driven DOC overproduction resulting in hypertension remission and improvement of the virilization symptoms.

Project description:BackgroundCumulative exposure to high glucocorticoid levels is detrimental for the brain and may have particular implications in later life. A feature of late-life depression is increased cortisol secretion. Variants in the CYP11B1 gene, which codes for the enzyme responsible for cortisol synthesis, could influence risk of late-life depression, but this hypothesis has not been examined. We investigated the associations between variants in the CYP11B1 gene and late-life depression, taking into account history of depression and potential sex-specific effects.MethodsWe assessed depression in 1007 community-dwellers aged 65 years or older (60% women) at baseline and over a 14-year follow-up. A clinical level of depression was defined as a score of ≥ 16 on the Centre for Epidemiology Studies Depression scale or a diagnosis of current major depression based on the Mini-International Neuropsychiatric Interview and according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV). We examined incident and recurrent depression in participants without or with a history of major depression, respectively. We genotyped 5 single-nucleotide polymorphisms (SNPs) spanning CYP11B1. We used multivariable analyses to adjust for age, body mass index, cardiovascular ischemic pathologies, hypertension, cognitive impairment and anxiety.ResultsIn women, rs6471580 and rs7016924 were associated with a 50% lower rate of incident (new-onset) late-life depression, and rs11783855 was associated with a 2.4-fold higher rate of late-life depression. These associations remained after correction for multiple testing, but we found no associations for recurrent depression in women or men.LimitationsThis study focused on the major gene involved in corticosteroid biosynthesis, but other genes may also be implicated in this pathway.ConclusionVariants of the CYP11B1 gene appear to be susceptibility factors for late-life depression in a sex-specific manner.

Project description:Objective: 11β-hydroxylase deficiency (11βOHD) is a rare autosomal recessive disorder caused by mutations in the CYP11B1 gene. It is characterized by virilization, hypertension, and significant final height impairment. In this study, we aim to investigate the clinical and molecular characteristics of four unrelated Chinese patients with 11βOHD disorder. Methods: The clinical information of four 11βOHD patients were carefully reviewed. Genetic analysis was performed using next-generation sequencing (NGS) based panel analysis. NGS coverage depth was analyzed to detect exonic copy-number variants (CNVs) on patient 1. Quantitative PCR (qPCR) was subsequently performed to confirm the CNVs detected from the NGS coverage depth analysis. Results: The mean age of the patients at diagnosis was 4.7 years (range, 2.0-9.3 years). Two genetically female patients (patients 1 and 2) with 11βOHD presented severe virilization of external genitalia and were raised as males. Two genetically male patients (patients 3 and 4) presented precocious puberty. Additionally, patients 1, 3, and 4 presented with hypertension. In patient 4, unilateral adrenal mass was detected and removed at the age of 9 years. Interestingly, the height of patient 4 (174.4 cm, +6.7 SD) wasn't impaired and reached his mid-parental height (173 cm). Three novel variants in the CYP11B1 gene (c.1150_1153del, c.217C>T, and c.400G>C) were identified by NGS. Various bioinformatics tools revealed potential pathogenic effects for the novel variants, and evolutionary-conservation revealed that the novel missense variant affected an amino acid that is highly conserved among species. Furthermore, NGS coverage depth analysis and qPCR identified a novel heterozygous deletion of exons 1-6 in patient 1. Conclusion: Our study expands the spectrum of mutations of the CYP11B1 gene in Chinese population. In addition, We reported the first case of a patient with classical 11βOHD disorder, whose final height wasn't compromised.

Dataset Information

Detection of Small CYP11B1 Deletions and One Founder Chimeric CYP11B2/CYP11B1 Gene in 11β-Hydroxylase Deficiency.

Objective

Methods

Results

Conclusions

Publications

Detection of Small <i>CYP11B1</i> Deletions and One Founder Chimeric <i>CYP11B2/CYP11B1</i> Gene in 11β-Hydroxylase Deficiency.

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