Disorders of sex development (DSD) are congenital conditions in which chromosomal, gonadal, or phenotypic sex is atypical. Clinical management of DSD is often difficult and currently only 13% of patients receive an accurate clinical genetic diagnosis. To address this we have developed a massively parallel sequencing targeted DSD gene panel which allows us to sequence all 64 known diagnostic DSD genes and candidate genes simultaneously. We analyzed DNA from the largest reported international cohort of patients with DSD (278 patients with 46,XY DSD and 48 with 46,XX DSD). Our targeted gene panel compares favorably with other sequencing platforms. We found a total of 28 diagnostic genes that are implicated in DSD, highlighting the genetic spectrum of this disorder. Sequencing revealed 93 previously unreported DSD gene variants. Overall, we identified a likely genetic diagnosis in 43% of patients with 46,XY DSD. In patients with 46,XY disorders of androgen synthesis and action the genetic diagnosis rate reached 60%. Surprisingly, little difference in diagnostic rate was observed between singletons and trios. In many cases our findings are informative as to the likely cause of the DSD, which will facilitate clinical management. Our massively parallel sequencing targeted DSD gene panel represents an economical means of improving the genetic diagnostic capability for patients affected by DSD. Implementation of this panel in a large cohort of patients has expanded our understanding of the underlying genetic etiology of DSD. The inclusion of research candidate genes also provides an invaluable resource for future identification of novel genes.

https://repub.eur.nl/pub/94541/REPUB_94541_OA.pdf

Disorders of sex development: insights from targeted gene sequencing of a large international patient cohort

Massive palindromes in the human Y chromosome harbor mirror-image gene pairs essential for spermatogenesis. During evolution, these gene pairs have been maintained by intrapalindrome, arm-to-arm recombination. The mechanism of intrapalindrome recombination and risk of harmful effects are unknown. We report 51 patients with isodicentric Y (idicY) chromosomes formed by homologous crossing over between opposing arms of palindromes on sister chromatids. These ectopic recombination events occur at nearly all Y-linked palindromes. Based on our findings, we propose that intrapalindrome sequence identity is maintained via noncrossover pathways of homologous recombination. DNA double-strand breaks that initiate these pathways can be alternatively resolved by crossing over between sister chromatids to form idicY chromosomes, with clinical consequences ranging from spermatogenic failure to sex reversal and Turner syndrome. Our observations imply that crossover and noncrossover pathways are active in nearly all Y-linked palindromes, exposing an Achilles' heel in the mechanism that preserves palindrome-borne genes.

Isodicentric Y Chromosomes and Sex Disorders as Byproducts of Homologous Recombination that Maintains Palindromes

Background: Androgen receptor (AR) gene mutations are the most frequent cause of 46,XY disorders of sex development (DSD) and are associated with a variety of phenotypes, ranging from phenotypic women [complete androgen insensitivity syndrome (CAIS)] to milder degrees of undervirilization (partial form or PAIS) or men with only infertility (mild form or MAIS). Objective: The aim of the study was to characterize the contribution of the AR gene to the molecular cause of 46,XY DSD in a series of Spanish patients. Setting: We studied a series of 133 index patients with 46,XY DSD in whom gonads were differentiated as testes, with phenotypes including varying degrees of undervirilization, and in whom the AR gene was the first candidate for a molecular analysis. Methods: The AR gene was sequenced (exons 1 to 8 with intronic flanking regions) in all patients and in family members of 61% of AR-mutated gene patients. Results: AR gene mutations were found in 59 individuals (44.4% of index patients), of whom 46 (78%)...

/pdf/novel-60-and-recurrent-40-androgen-receptor-gene-mutations-4ljidx6dld.pdf

Novel (60%) and Recurrent (40%) Androgen Receptor Gene Mutations in a Series of 59 Patients with a 46,XY Disorder of Sex Development

MicroRNAs (miRNAs) are secreted by cells in vesicles, bound in a ribonucleoprotein complex or as free molecules. These miRNA secretion pathways are dysregulated in cancer, making miRNAs attractive candidate molecules for liquid biopsies. A number of studies have investigated the regulation of miRNA secretion into blood and urine and suggested that miRNAs are noninvasive diagnostic, prognostic and surveillance markers in urological carcinomas, and research in this area has increased over the past 5 years. However, methodological and analytical pitfalls exist and require addressing to enable future translation of the laboratory findings regarding miRNAs as biomarkers into clinical practice in bladder cancer, kidney cancer, prostate cancer and testicular cancer.

/pdf/the-translational-potential-of-micrornas-as-biofluid-markers-1kmdjx3a50.pdf

The translational potential of microRNAs as biofluid markers of urological tumours

microRNAs (miRNAs) are small non-coding RNAs that control gene expression posttranscriptionally and are part of the giant non codifying genoma. Cumulating data suggest that miRNAs are promising potential biomarkers for many diseases, including cancer. Prostate cancer (PCa) detection is currently based in the serum prostate-specific antigen biomarker and digital rectal examination. However, these methods are limited by a low predictive value and the adverse consequences associated with overdiagnosis and overtreatment. New biomarkers that could be used for PCa detection and prognosis are still needed. Recent studies have demonstrated that aberrant expressions of microRNAs are associated with the underlying mechanisms of PCa. This review attempts to extensively summarize the current knowledge of miRNA expression patterns, as well as their targets and involvement in PCa pathogenesis. We focused our review in the value of circulating and urine miRNAs as biomarkers in PCa patients, highlighting the existing discrepancies between different studies, probably associated with the important methodological issues related to their quantitation and normalization. The majority of studies have been performed in serum or plasma, but urine obtained after prostate massage appears as a new way to explore the usefulness of miRNAs. Large screening studies to select a miRNA profile have been completed, but bioinformatics tools appear as a new approach to select miRNAs that are relevant in PCa development. Promising preliminary results were published concerning miR-141, miR-375 and miR-21, but larger and prospective studies using standardized methodology are necessary to define the value of miRNAs in the detection and prognosis of PCa.

https://www.degruyter.com/downloadpdf/j/cclm.2017.55.issue-5/cclm-2015-1073/cclm-2015-1073.xml

miRNAs as novel biomarkers in the management of prostate cancer.

To compare the expression of two promising circulating micro-ribonucleic acids (miRNAs 21 and 221) in patients with prostate cancer to subjects without cancer and to evaluate their potential role as specific noninvasive molecular biomarkers for prostate cancer diagnosis, circulating miRNAs 21 and 221 expression profiles were analyzed in 20 men aged 50–75 years, presenting with lower urinary tract symptoms (LUTSs) and undergoing transrectal ultrasound (TRUS)-guided prostate biopsy based on either elevated serum prostate-specific antigen (PSA) (>4.0 ng/ml) or suspicious digital rectal examination (DRE). The performance of miRNAs 21 and 221 in differentiating prostate cancer from nonmalignant cases was evaluated and compared to DRE and elevated PSA. miRNA 21 was overexpressed in 90 % of group A vs. 10 % of group B, while miRNA 221 was overexpressed in 80 % of group A vs. 20 % of group B (p = 0.001). MiRNA 21 overexpression had the highest performance as a diagnostic test with a sensitivity of 90 % and a specificity 90 % (p = 0.02). No correlations were noted between Gleason score of prostate cancer cases and relative quantity (RQ) 21 (r = −0.355, p = 0.292) or RQ 221 (r = −0.044, p = 0.892). Our study showed that serum miRNAs 21 and 221 expression profiling tests may be used as specific noninvasive molecular biomarkers for prostate cancer diagnosis due to their higher sensitivity and specificity with a high negative predictive value leading to a decrease in the biopsies taken for patients with elevated serum PSA values.

Circulating miRNAs 21 and 221 as biomarkers for early diagnosis of prostate cancer

Extracellular miR-145, miR-223 and miR-326 expression signature allow for differential diagnosis of immune-mediated neuroinflammatory diseases

The phenotypic spectrum of patients carrying NR5A1 mutations ranges from 46,XY gonadal dysgenesis to male infertility. Phenotypic variability could be due to digenic or oligogenic inheritance of pathogenic variants in other testis-determining genes. Here, exome sequencing identified 2 pathogenic de novo NR5A1 mutations in 2 patients with 46,XY gonadal dysgenesis, p.Q206Tfs*20 and p.Arg313Cys. The latter patient also carried a missense mutation in MAP3K1. Our data extend the number of NR5A1 gene mutations associated with gonadal dysgenesis. The combination of an NR5A1 mutation with a MAP3K1 variant may explain the phenotypic variability associated with NR5A1 mutations.

Identification of NR5A1 Mutations and Possible Digenic Inheritance in 46,XY Gonadal Dysgenesis.

Isodicentric chromosome formation is the most common structural abnormality of the Y chromosome. As dicentrics are mitotically unstable, they are subsequently lost during cell division resulting in mosaicism with a 45,X cell line. We report on six patients with variable signs of disorders of sex development (DSD) including ambiguous genitalia, short stature, primary amenorrhea, and male infertility with azoospermia. Cytogenetic studies showed the presence of a sex chromosome marker in all patients; associated with a 45,X cell line in five of them. Fluorescence in situ hybridization (FISH) technique was used to determine the structure and the breakage sites of the markers that all proved to be isodicentric Y chromosomes. Three patients, were found to have similar breakpoints: idic Y(qter→ p11.32:: p11.32→ qter), two of them presented with ambiguous genitalia and were found to have ovotesticular DSD, while the third presented with short stature and hypomelanosis of Ito. One female patient presenting with primary amenorrhea, Turner manifestations and ambiguous genitalia revealed the breakpoint: idic Y (pter→q11.1::q11.1→pter). The same breakpoint was detected in a male with azoospermia but in non-mosaic form. An infant with ambiguous genitalia and mixed gonadal dysgenesis (MGD) had the breakpoint at Yq11.2: idic Y(pter→q11.2::q11.2→pter). SRY signals were detected in all patients. Sequencing of the SRY gene was carried out for three patients with normal results. This study emphasizes the importance of FISH analysis in the diagnosis of patients with DSD as well as the establishment of the relationship between phenotype and karyotype.

Isodicentric Y chromosomes in Egyptian patients with disorders of sex development (DSD).

Androgen resistance syndromes [i.e. 5 alpha-reductase deficiency (5 alpha RD) and androgen receptor (AR) defects] are frequently reported among Egyptian intersex patients. This study examined AR and 5 alpha-reductase 2 (5 alpha R2) gene mutations among a sample of such cases as a first step towards instituting a screening program. Five families with a typical hormonal profile of 5 alpha RD were screened for major deletions of exons 3-5 of the 5 alpha R2 gene, using polymerase chain reaction (PCR) and electrophoresis. Thereafter, screening for point mutations was carried out by single strand conformational polymorphism (SSCP) analysis, followed by nucleotide sequencing. Seven patients with androgen insensitivity syndrome (AIS) were subjected to molecular analysis of AR exons B-H by a similar protocol, except for the use of denaturing gradient gel electrophoresis (DGGE) for screening point mutations. No major deletions were found in either gene. One family had abnormal electrophoretic mobility on SSCP of exon 5 of the 5 alpha R2 gene, resulting from a point mutation (C to T substitution) at codon 246. Another family, showing retarded mobility on DGGE, had a point mutation (G to A substitution) at codon 889 of the AR gene. In conclusion, the study revealed two mutations previously reported in other geographically distinct populations, inferring the possibility of mutational hot spots in the genes.

Mona L. Essawi

Papers

Circulating miRNAs 21 and 221 as biomarkers for early diagnosis of prostate cancer

Extracellular miR-145, miR-223 and miR-326 expression signature allow for differential diagnosis of immune-mediated neuroinflammatory diseases

Identification of NR5A1 Mutations and Possible Digenic Inheritance in 46,XY Gonadal Dysgenesis.

Isodicentric Y chromosomes in Egyptian patients with disorders of sex development (DSD).

Molecular analysis of androgen resistance syndromes in Egyptian patients.