Genotyping of a Chinese family with 46,XX and 46,XY 17-hydroxylase deficiency

17 alpha-hydroxylase deficiency: A case report of young Chinese woman with a rare gene mutation

We report a young adult woman with 17 alpha-hydroxylase deficiency (17α-OHD) in Shandong province of China. The patient carried compound heterozygous mutations in the CYP17A1 gene: c.985-987 delinsAA (p.Tyr329LysfsX90) and c.1486C > T (p.Arg496Cys). The patient's hypertension and hypokalemia were resolved after taking medications of glucocorticoid, aldactone, and calcium antagonists.

Ovarian gonadoblastoma with dysgerminoma in a girl with 46,XX karyotype 17a-hydroxylase/17, 20-lyase deficiency: A case report and literature review

17α-hydroxylase/17,20-lyase deficiency (17-OHD), caused by mutations in the gene of the cytochrome P450 family 17 subfamily A member 1 (CYP17A1), is a rare type of congenital adrenal hyperplasia (CAH), usually characterized by cortisol and sex steroid deficiency combined with excessive mineralocorticoid. Gonadoblastoma is a relatively rare ovarian tumor that is frequently seen among patients with 46,XY gonadal dysgenesis. Rarely have they been reported in female patients with normal 46,XX karyotype. Here, we report an interesting case of an 11-year-old Chinese girl who presented acute abdominal pain that was later attributed to tumor rupture of right ovarian gonadoblastoma with dysgerminoma. Further evaluations revealed hypertension and hypokalemia. Hormonal findings showed increased progesterone, hypergonadotropic hypogonadism, and low cortisol levels. Her chromosome karyotype was 46,XX without Y chromosome material detected. Genetic analysis revealed that the patient had a homozygous pathogenic variant c.985_987delTACinsAA (p.Y329Kfs*90) in exon 6 of the CYP17A1 gene and that her parents were all heterozygous carriers of this pathogenic variant. Due to the variable clinical manifestations of 17-OHD, meticulous assessment including genetic analysis is necessary. Further study is warranted to unravel the mechanism of gonadoblastoma in a patient with normal karyotypes.

Prevalence of CYP17A1 gene mutations in 17α-hydroxylase deficiency in the Chinese Han population

BACKGROUND

17α-hydroxylase deficiency is a rare autosomal recessive disorder caused by mutations in the cytochrome P450 family 17 subfamily A member 1 gene. The major clinical presentation includes hypertension, hypokalemia, male pseudohermaphroditism and female gonadal dysplasia. Hundreds of pathogenic variants have been reported in this disorder, and some common mutations were found to be race-specific.

CASE PRESENTATION

In this study, we reported 5 Chinese girls with 17α-hydroxylase deficiency from Henan Province. The patients all came to the hospital for hypertension, and they also presented with sexual infantilism. The average age of the patients was 14 years old, ranging from 12 to 17 years old. They all had reduced blood cortisol, estradiol (E2), and testosterone (TESTO) and increased adrenocorticotropic hormone (ACTH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH). They all had the appearance of females; however, three of the chromosome karyotypes were 46XX, and two were 46XY.

CONCLUSIONS

All of the patients carried a mutation on the 329 amino acid of CYP17A1 exon 6. By summarizing the currently known pathogenic mutations of 17α-hydroxylase deficiency, we demonstrated the prevalence of these gene mutations in Chinese Han and non-Chinese populations.

Functional Identification of Compound Heterozygous Mutations in the CYP17A1 Gene Resulting in Combined 17α-Hydroxylase/17,20-Lyase Deficiency

BACKGROUND

We previously reported a patient with congenital adrenal hyperplasia (CAH) with compound heterozygous mutations in the cytochrome P450 17A1 (CYP17A1) gene. One allele had a p.His373Leu and the other a new p.Glu383fsX36 mutation. The aim of this study was to investigate the functional properties of a new allele present in a compound heterozygote of CYP17A1.

METHODS

To understand how p.His373Leu and p.Glu383fsX36 affect P450c17 enzymatic activity, wild type and mutant CYP17A1 cDNAs were cloned into flag-tagged pcDNA3 vector and introduced into human embryonic kidney cells 293T (HEK293T) cells. Protein expression levels of CYP17A1 were then analyzed. And the activities of 17α-hydroxylase and 17,20-lyase of CYP17A1 were evaluated by measuring the conversion of progesterone to 17α-hydroxyprogesterone and of 17α-hydroxypregnenolone to dehydroepiandrosterone, respectively. In addition a computer model was used to create the three-dimensional structure of the mutant CYP17A1 enzymes.

RESULTS

Production of the p.His373Leu mutant protein was significantly lower than that of the wild type protein, and the p.Glu383fsX36 protein was hardly produced. Similarly the enzymatic activity derived from the p.His373Leu mutant vector was significantly lower than that obtained from the wild type vector, and little activity was obtained from the p.Glu383fsX36 vector. Three-dimensional modeling of the enzyme showed that p.His373 was located in region important for heme-binding and proper folding. Neither the p.His373Leu nor the p.Glu383fsX36 mutant protein formed a heme-binding structure.

CONCLUSION

Enzyme activity measured in both mutants disappeared completely in both 17α-hydroxylase and 17,20-lyase. This result accounts for the clinical manifestations of the patient with the compound heterozygous CYP17A1 mutations.

Three new Brazilian cases of 17α-hydroxylase deficiency: clinical, molecular, hormonal, and treatment features

BACKGROUND

Deficiency of 17α-hydroxylase (17OHD) is a rare form of adrenal hyperplasia. Diagnosis is generally delayed, impairing appropriate treatment.

CASE PRESENTATION

Here, we report the clinical, molecular, hormonal, and treatment data of three unrelated 17OHD patients, aged 14-16 years with hypergonadotrophic hypogonadism; uncontrolled hypertension; primary adrenal insufficiency; and high progesterone, low to normal potassium, and low dehydroepiandrosterone, androstenedione, and testosterone levels. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) at baseline and after an adrenocorticotropic hormone test showed low cortisol and cortisone and high deoxycorticosterone (DOC) and corticosterone levels; both DOC/21-deoxycortisol and costicosterone/cortisol ratios were very high. Patient 2 had 46,XX karyotype and patients 1 and 3, had 46,XY. A molecular analysis showed that two of the patients were homozygous for p.W406R mutation and the other patient was compound heterozygous for p.W406R and p.P428L. Hypertension was controlled only after the administration of both prednisone and mineralocorticoid antagonist.

CONCLUSIONS

Hypertension in young women must lead to diagnostic suspicion, even in the pre-pubertal period. The basal level of progesterone is an indicator of 17OHD. Mineral and glucocorticoid ratios obtained from LC-MS/MS can reinforce the diagnosis. Hypertension can be controlled using glucocorticoid replacement therapy and mineralocorticoid antagonist.

Clinical and molecular manifestation of fifteen 17OHD patients: a novel mutation and a founder effect

17-hydroxylase deficiency (17OHD) has long been regarded as a rare form of congenital adrenal hyperplasia, inherited in an autosomal recessive pattern. Fifteen patients with 17OHD were described from clinical manifestations and hormone profile. Then, CYP17A1 gene was amplified and sequenced in a new patient. Heterozygous mutations c. 431_433del, p.K144del/c. 985_987delinsAA, p.Y329 fs were identified. Functional study indicated the novel mutation K144del completely abolished enzyme activity. In the three-dimensional model, the K144del mutation completely destroyed the alpha helix in the steroid binding domain. Sixteen SNPs within CYP17A1 gene were selected and genotyped in 7 unrelated families to determine whether Y329 fs had founder effect in China. Haplotyping study showed that all c. 985_987delinsAA mutation shared the same haplotype. However, from GWAS data of 2760 controls, this special haplotype was found only in one chromosome. In conclusion, we identified a novel (K144del) and a widely reported (Y329 fs) heterozygous mutations of CYP17A1 gene from a 17OHD patient. Haplotyping analysis showed the common mutation Y329 fs in China came from the same ancestor, which explains the reason that 17OHD was the second cause of CAH in China.

A new compound heterozygous mutation in the CYP17A1 gene in a female with 17α-hydroxylase/17,20-lyase deficiency

BACKGROUND

Congenital adrenal hyperplasia due to 17α-hydroxylase/17,20-lyase deficiency (OMIM #202110) is a rare autosomal recessive disorder, which is caused by mutations of the CYP17A1 gene located on chromosome 10q24.3. It has been reported that the type of mutation of the CYP17A1 gene was associated with the extent of 17α-hydroxylase/17,20-lyase deficiency, and the prevalence of common mutation was different among ethnic groups.

CASE

A 21-year-old Korean female presented with primary amenorrhea and sexual infantilism, and intermittent hypokalemic episodes. Laboratory test was consistent with hypergonadotropic hypogonadism. The karyotype was 46,XX[20]. Genomic DNA was extracted from peripheral blood leukocytes. All the eight exons of the CYP17A1 gene including flanking regions of introns were amplified by PCR. The mutations of the CYP17A1 gene were detected by direct sequencing. A compound heterozygous mutation was identified; one allele had a missense mutation of c.1118A>T (p.His373Leu), which was reported previously and induced the complete loss of both 17α-hydroxylase/17,20-lyase activity. This mutation has been known to be one of the common mutation types in East Asia. The other allele had a novel 1-bp deletion c.1148delA causing frameshift, premature termination codon (p.Glu383fs) and induced truncated enzymes.

CONCLUSION

Our experience for stepwise clinical, laboratory and molecular approach would be helpful to diagnose these patients accurately and understand the genetic events in 17α-hydroxylase/17,20-lyase deficiency patients.

CYP17A1 mutations identified in 17 Chinese patients with 17α-hydroxylase/17,20-lyase deficiency

CONTEXT

17α-hydroxylase deficiency (17OHD) is a relatively rare disease, accounting for about 1% of congenital adrenal hyperplasia cases. The CYP17A1 gene mutation can lead to this disease. Human CYP17A1 gene is located on chromosome 10q24.3. It consists of eight exons encoding 508 amino acids. To date, more than 50 mutations in exons and introns of the CYP17A1 gene have been reported to cause complete or partial 17OHD.

OBJECTIVE

The aim of this study was to investigate the CYP17A1 gene mutation types in 17 Chinese patients, containing 11 complete and six partial 17OHD patients.

SETTING

We conducted the study in the Department of Obstetrics and Gynecology of Peking Union Medical College Hospital.

PATIENTS

Seventeen patients were studied with complete or partial 17OHD.

MAIN OUTCOME MEASURES

The CYP17A1 gene was sequenced and we measured steroid and sex hormone levels.

RESULTS

Analysis of the CYP17A1 gene in our patients revealed 12 different kinds of mutation. Two mutations (IVS1-1G>A and L209P) were novel mutations. Mutation c.985_987delTACinsAA (Y329KfsX418) in Exon 6 was the most common mutation in Chinese patients, accounting for 50 percents of the mutant alleles (17/34). Exon 6 was the hot spot since most mutations were detected in this exon (59%, 20/34 alleles). There was no mutation detected in the Exons 4 and 5.

17α-hydroxlyase/17, 20-lyase deficiency in three siblings with primary amenorrhea and absence of secondary sexual development

BACKGROUND

17α-hydroxlyase/17, 20-lyase deficiency (17OHD) is a rare phenotype of congenital adrenal hyperplasia that can cause primary amenorrhea.

CASE

Three phenotypically female siblings visited the adolescent gynecologic clinic complaining of primary amenorrhea and absence of secondary sexual developments. All had constant high blood pressure and showed a hypergonadotropic hypogonadal state with high progesterone and low testosterone levels. Two were genotypically females and one was genotypically a male; all were confirmed to have 17OHD, and estrogen replacement, glucocorticoids, and antihypertensive drugs were Prescribed to the patients.

SUMMARY AND CONCLUSION

Identifying a 17OHD patient complaining of primary amenorrhea in a gynecologic clinic is important for proper management.

Molecular study of five Chinese patients with 46XX partial 17a-hydroxylase/17,20-lyase deficiency

CONTEXT

Partial 17a-hydroxylase/17,20 lyase deficiency (17OHD) is a rare subtype of 17OHD caused by CYP17 gene mutations.

OBJECTIVE

Five Chinese 46,XX patients and one family with partial 17OHD were genotyped.

PATIENTS

The five patients derived from different families and one of them had another patient in family. The diagnosis of partial 17OHD was established through clinical and laboratory characteristics in Peking Union Medical College Hospital, China, from 2000 to 2010.

RESULTS

Seven CYP17 gene mutations are identified from these patients. Among them, R449C and L209P are two novel missense mutations. Four patients are found to have a compound heterozygous mutations and one patient has only one mutation. The patients with family history are also found to have parent origin of gene mutations.

CONCLUSION

Two novel missense mutations in CYP1 7 are found in this study. Comparing with previous reports, the different combination of mutations may have various effects on the activities of the 17-hydroxylase and/or17,20-lyase.