Clinical and molecular genetic features of cases of isolated hypogonadotropic hypogonadism, associated with defects in <i>GNRHR</i> genes

Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder characterised by lack of pubertal development and infertility, due to deficient production, secretion or action of gonadotropin-releasing hormone (GnRH). Clinically, there are variants of CHH with hypo-/anosmia (Kalman syndrome) and normosmic hypogonadotropic hypogonadism. Given a growing list of gene mutations accounting for CHH, the application of next generation sequencing (NGS) comprises an excellent molecular diagnostic approach because it enables the simultaneous evaluation of many genes. Biallelic mutations in GNRHR gene lead to the development of hypogonadotropic hypogonadism with normosmia. In this paper, we describe 16 patients with proven GnRH resistance and estimate the frequency of pathogenic variants in the GNRHR gene in the Russian population.

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Idiopathic hypogonadotropic hypogonadism: a rare cause of primary amenorrhoea in adolescence—a review and update on diagnosis, management and advances in genetic understanding.

BMJ Case Reports ◽

10.1136/bcr-2020-239495 ◽

2021 ◽

Vol 14 (4) ◽

pp. e239495

Author(s):

Grace Cham ◽

Brooke O'Brien ◽

Rebecca MN Kimble

Keyword(s):

Genetic Disorders ◽

Pubertal Development ◽

Hypogonadotropic Hypogonadism ◽

Gene Mutations ◽

Serum Levels ◽

Breast Development ◽

Idiopathic Hypogonadotropic Hypogonadism ◽

Primary Amenorrhoea ◽

Normal Menstrual Cycle ◽

Uterine Growth

Idiopathic hypogonadotropic hypogonadism (IHH) refers to a family of genetic disorders that affect the production and/or action of gonadotropic-releasing hormone, resulting in reduced serum levels of sex steroids. This condition has a prevalence of 1–10 cases/100 000 births and is characterised by the absence of spontaneous pubertal development. In women, the condition is characterised by the onset of normal adrenarche, with the absence of thelarche and menarche. Pubertal induction for breast development and uterine growth with oestradiol, and sequential maintenance of a normal menstrual cycle and adequate oestrogen for bone health, with an oestrogen and progesterone, is considered first-line treatment. Pregnancy can be achieved in patients who have received and responded to treatment with ovulation induction with exogenous gonadotrophins. Advances in genetic testing have led to increased research and understanding of the underlying genetics of IHH with gene mutations described in up to 50% of all IHH cases.

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Genetic investigation of 211 Chinese families expands the mutational and phenotypical spectra of hereditary retinopathy genes through targeted sequencing technology

BMC Medical Genomics ◽

10.1186/s12920-021-00935-w ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Zhouxian Bai ◽

Yanchuan Xie ◽

Lina Liu ◽

Jingzhi Shao ◽

Yuying Liu ◽

...

Keyword(s):

Sanger Sequencing ◽

Molecular Genetic ◽

Gene Mutations ◽

Central China ◽

Targeted Sequencing ◽

Sequencing Data ◽

Targeted Next Generation Sequencing ◽

Pathogenic Variants ◽

Number Of Patients ◽

Ophthalmologic Examination

Abstract Background Hereditary retinopathy is a significant cause of blindness worldwide. Despite the discovery of many mutations in various retinopathies, a large number of patients remain genetically undiagnosed. Targeted next-generation sequencing of the human genome is a suitable approach for the molecular diagnosis of retinopathy. Methods We describe a cohort of 211 families from central China with various forms of retinopathy; 95 patients were investigated using multigene panel sequencing, and the other 116 with suspected Leber hereditary optic neuropathy (LHON) were tested by Sanger sequencing. The detected variation of targeted sequencing was verified by PCR-based Sanger sequencing. We performed a comprehensive analysis of the cases using sequencing data and ophthalmologic examination information. Results Potential causal mutations were identified in the majority of families with retinopathy (57.9% of 95 families) and suspected LHON (21.6% of 116 families). There were 68 variants of a certain significance distributed in 31 known disease-causing genes in the 95 families; 37 of the variants are novel and have not been reported to be related to hereditary retinopathy. The NGS panel solution provided a 45.3% potential diagnostic rate for retinopathy families, with candidate gene mutations of undefined pathogenicity revealed in another 12.6%of the families. Conclusion Our study uncovered novel mutations and phenotypic aspects of retinopathy and demonstrated the genetic and clinical heterogeneity of related conditions. The findings show the detection rate of pathogenic variants in patients with hereditary retinopathy in central China as well as the diversity and gene distribution of these variants. The significance of molecular genetic testing for patients with hereditary retinopathy is also highlighted.

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Spectrum and frequency of GJB2 (Cx26) gene mutations in patients with hearing impairments in the Republic of Buryatia

Nauchno-prakticheskii zhurnal «Medicinskaia genetika» ◽

10.25557/2073-7998.2021.07.26-36 ◽

2021 ◽

pp. 26-36

Author(s):

В.Г. Пшенникова ◽

А.М. Чердонова ◽

Ф.М. Терютин ◽

Г.П. Романов ◽

А.В. Соловьев ◽

...

Keyword(s):

Molecular Genetic ◽

Gene Mutations ◽

Total Sample ◽

Molecular Genetic Analysis ◽

Gjb2 Gene ◽

Hearing Impairments ◽

C 23 ◽

Syndromic Hearing Loss ◽

The Republic ◽

Biallelic Mutations

В диагностике наследственной несиндромальной потери слуха высокую информативность обеспечивают методы молекулярно-генетического анализа мутаций гена GJB2 (Cx26). Впервые в Республике Бурятия (Восточная Сибирь) путем прямого секвенирования были определены спектр и частота мутаций гена GJB2 у 165 индивидов с нарушениями слуха. В обследованной выборке было обнаружено 13 известных аллельных вариантов гена GJB2 (c.-254C>T, c.-49G>A, c.-23+1G>A, c.35delG, c.79G>A, c.101T>C, c.109G>A, c.235delC, c.299_300delАТ, c.327_328delinsA, c.341A>G, c.457G>A и c.516G>C). У пациентов бурятов мутационный спектр был представлен пятью патогенными GJB2-вариантами: c.-23+1G>A (4,1%), c.109G>A (0,6%), c.235delC (1,4%), c.327_328delGGinsA (0,6%), c.516G>C (0,6%). Среди русских пациентов было обнаружено пять мутаций: c.35delG (25,7%), c.-23+1G>A (3,3%), c.101Т>С (0,6%), c.109G>A (1,9%), c.299_300delАТ (0,6%). Вклад биаллельных мутаций гена GJB2 в этиологию потери слуха в общей выборке пациентов из Бурятии составил 15,8% (26/165). При распределении пациентов по этнической принадлежности вклад биаллельных мутаций гена GJB2 в этиологию потери слуха у русских составил 28,9% (22/76), в то время как у бурятов лишь 5,1% (4/79). Таким образом, результаты нашего исследования свидетельствуют о том, что мутации гена GJB2 не являются основной причиной потери слуха у бурятов. Вероятно, у большей части GJB2-негативных пациентов потеря слуха может быть обусловлена мутациями в других генах, ответственных за развитие наследственных нарушений слуха. In the diagnosis of hereditary non-syndromic hearing loss (HL), the methods of molecular genetic analysis of the GJB2 (Cx26) gene mutations provide high valuable information. For the first time, in the Republic of Buryatia (Eastern Siberia), the spectrum and frequency of GJB2 gene mutations were determined in a sample of 165 individuals with HL using sequencing of significant regions of the GJB2 gene. A total of 13 known allelic variants were found (c.-254C>T, c.-49G>A, c.-23+1G>A, c.35delG, c.79G>A, c.101T>C, c.109G>A, c.235delC, c.299_300delAT, c.327_328delinsA, c.341A>G, c.457G>A u c.516G>C). In the sample of Buryat patients, the mutation spectrum was represented by five GJB2 variants: c.-23+1G>A (4.1%), c.109G>A (0.6%), c.235delC (1.4%), c.327_328delGGinsA (0.6%), c.516G>C (0.6%). Five mutations were found among Russian patients: c.35delG (25.7%), c.-23+1G>A (3.3%), c.109G>A (1.9%), c.101T>C (0.6%), c.299_300delAT (0.6%). In general, the contribution of biallelic mutations of the GJB2 gene to the etiology of HL in the total sample of patients in Buryatia was 15.8% (26/165). When the total sample of patients was divided by ethnicity the contribution of biallelic mutations of the GJB2 gene to the etiology of HL in Buryat patients was 5.1% (4/79), and in Russian patients - 28.9% (22/76). Thus, the results of our study indicate that the mutations in the GJB2 gene are not the main cause of HL in Buryats. Probably, in some GJB2-negative patients (84.2% in our study), HL may be due to the mutations in other genes responsible for the development of hereditary hearing impairments.

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Spectrum of DICER1 Germline Pathogenic Variants in Ovarian Sertoli–Leydig Cell Tumor

Journal of Clinical Medicine ◽

10.3390/jcm10091845 ◽

2021 ◽

Vol 10 (9) ◽

pp. 1845

Author(s):

Elisa De Paolis ◽

Rosa Maria Paragliola ◽

Paola Concolino

Keyword(s):

Leydig Cell ◽

Case Reports ◽

Molecular Genetic ◽

Young Female ◽

Micro Rna ◽

Loss Of Function ◽

Pathogenic Variants ◽

Genetic Features ◽

Dicer1 Syndrome ◽

Significant Discovery

Sertoli–Leydig Cell Tumors (SLCTs) are rare ovarian sex cord-stromal neoplasms, which predominantly affect adolescents and young female adults. The SLCTs clinical diagnosis and treatment remains challenging due to the rarity and the varied presentation. A large majority of SLCTs are unilateral, but also bilateral neoplasms have been reported, sometimes in the context of DICER1 syndrome. In fact, the most significant discovery regarding the molecular genetics basis of SLCTs was the finding of somatic and germline pathogenic variants in the DICER1 gene. The DICER1 protein is a key component of the micro-RNA processing pathway. Germline DICER1 pathogenic variants are typically inherited in an autosomal dominant pattern and are most often loss-of-function variants dispersed along the length of the gene. Contrarily, DICER1-related tumors harbor a characteristic missense “RNase IIIb hotspot” mutation occurring in trans, or, less frequently, loss of heterozygosity (LOH) event involving the wild-type allele. While DICER1 mutations have been identified in approximately 60% of SLCTs, especially in the moderately or poorly differentiated types, there are only a few case reports of ovarian SLCT with underlying germline DICER1 mutations. In this review, we focus on the molecular genetic features of SLCT, performing an extensive survey of all germline pathogenic variants modifying the whole sequence of the DICER1 gene. We point out that DICER1 genetic testing, coupled with an accurate variants classification and timely counseling, is of crucial importance in the clinical management of ovarian SLCT-affected patients.

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GNRHR biallelic and digenic mutations in patients with normosmic congenital hypogonadotropic hypogonadism

Endocrine Connections ◽

10.1530/ec-17-0104 ◽

2017 ◽

Vol 6 (6) ◽

pp. 360-366 ◽

Cited By ~ 6

Author(s):

Catarina I Gonçalves ◽

José M Aragüés ◽

Margarida Bastos ◽

Luísa Barros ◽

Nuno Vicente ◽

...

Keyword(s):

Autosomal Recessive ◽

Pubertal Development ◽

Hypogonadotropic Hypogonadism ◽

Autosomal Recessive Inheritance ◽

Cross Sectional Study ◽

Cross Sectional ◽

Congenital Hypogonadotropic Hypogonadism ◽

Frameshift Deletion ◽

Monoallelic Mutation ◽

Biallelic Mutations

Objective Normosmic congenital hypogonadotropic hypogonadism (nCHH) is a rare disorder characterised by lack of pubertal development and infertility, due to deficient production, secretion or action of gonadotropin-releasing hormone (GnRH) and, unlike Kallmann syndrome, is associated with a normal sense of smell. Mutations in the GNRHR gene cause autosomal recessive nCHH. The aim of this study was to determine the prevalence of GNRHR mutations in a group of 40 patients with nCHH. Design Cross-sectional study of 40 unrelated patients with nCHH. Methods Patients were screened for mutations in the GNRHR gene by DNA sequencing. Results GNRHR mutations were identified in five of 40 patients studied. Four patients had biallelic mutations (including a novel frameshift deletion p.Phe313Metfs*3, in two families) in agreement with autosomal recessive inheritance. One patient had a heterozygous GNRHR mutation associated with a heterozygous PROKR2 mutation, thus suggesting a possible role of synergistic heterozygosity in the pathogenesis of the disorder. Conclusions This study further expands the spectrum of known genetic defects associated with nCHH. Although GNRHR mutations are usually biallelic and inherited in an autosomal recessive manner, the presence of a monoallelic mutation in a patient should raise the possibility of a digenic/oligogenic cause of nCHH.

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Simultaneous Detection of NF1, SPRED1, LZTR1, and NF2 Gene Mutations by Targeted NGS in an Italian Cohort of Suspected NF1 Patients

Genes ◽

10.3390/genes11060671 ◽

2020 ◽

Vol 11 (6) ◽

pp. 671

Author(s):

Donatella Bianchessi ◽

Maria Cristina Ibba ◽

Veronica Saletti ◽

Stefania Blasa ◽

Tiziana Langella ◽

...

Keyword(s):

Simultaneous Detection ◽

Gene Mutations ◽

Neurofibromatosis Type ◽

Pathogenic Variant ◽

Large Deletions ◽

Pathogenic Variants ◽

Legius Syndrome ◽

Nf1 Gene ◽

One Year ◽

Next Generation Sequencing Ngs

Neurofibromatosis type 1 (NF1) displays overlapping phenotypes with other neurocutaneous diseases such as Legius Syndrome. Here, we present results obtained using a next generation sequencing (NGS) panel including NF1, NF2, SPRED1, SMARCB1, and LZTR1 genes on Ion Torrent. Together with NGS, the Multiplex Ligation-Dependent Probe Amplification Analysis (MLPA) method was performed to rule out large deletions/duplications in NF1 gene; we validated the MLPA/NGS approach using Sanger sequencing on DNA or RNA of both positive and negative samples. In our cohort, a pathogenic variant was found in 175 patients; the pathogenic variant was observed in NF1 gene in 168 cases. A SPRED1 pathogenic variant was also found in one child and in a one year old boy, both NF2 and LZTR1 pathogenic variants were observed; in addition, we identified five LZTR1 pathogenic variants in three children and two adults. Six NF1 pathogenic variants, that the NGS analysis failed to identify, were detected on RNA by Sanger. NGS allows the identification of novel mutations in five genes in the same sequencing run, permitting unambiguous recognition of disorders with overlapping phenotypes with NF1 and facilitating genetic counseling and a personalized follow-up.

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Molecular and genetic features of colorectal carcinoma: pathomorphological demonstration of clinical cases and literature review

Morphologia ◽

10.26641/1997-9665.2021.2.59-67 ◽

2021 ◽

Vol 15 (2) ◽

pp. 59-67

Author(s):

I.S. Shpon'ka ◽

O.O. Bondarenko ◽

I.O. Molokova

Keyword(s):

Colorectal Carcinoma ◽

Literature Review ◽

Molecular Genetic ◽

Tumor Grade ◽

Molecular Diagnostic ◽

Morbidity Rate ◽

City Region ◽

Kras Gene ◽

Genetic Features ◽

Formalin Fixed Paraffin Embedded

Background. Colorectal carcinoma (CRC) is one of the most widespread malignancies worldwide; its morbidity rate is on the third place amidst the most common cancers. According to present data, such molecular markers as CyD1, HIF1α, LC3B, p21, p53 as well as the detection of KRAS gene amplification could be used for evaluation of tumor grade, its invasiveness, risk of metastases, sensitivity to anti-EGFR treatment, and further prognosis for patient’s survive. Objective. The purpose of this study was to make a literature review of the CRC molecular diagnostic approaches and demonstrate 5 cases of colorectal carcinoma in patients of Dnipro-city region in purpose to reveal their molecular-genetic features. Methods. Five formalin fixed paraffin embedded specimens of colorectal carcinoma from patients of Dnipro-city region were evaluated pathomorphologically with histological, immunohistochemical and fluorescence in situ hybridization methods. Results. Case study revealed increased level of p53, p21, and LC3B expression, minor elevation of CyD1 and HIF1α expression in demonstrated samples. Amplification of KRAS gene was not found. Conclusion. Our data analysis had revealed multiple studies dedicated to CRC molecular diagnostics with controversial results, what could be explained by both variable methodological approaches and epidemiological peculiarities of CRC in different sites of the globe. Therefore, there is a necessity in empirical identification of the molecular-genetic features of colorectal carcinomas in patients of our region that could improve current state of the art in CRC diagnostic and treatment approaches. Achieved data are the result of the trial and our research of this issue is ongoing.

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Novel missense mutation of SASH1 in a Chinese family with dyschromatosis universalis hereditaria

BMC Medical Genomics ◽

10.1186/s12920-021-01014-w ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Lu Cao ◽

Ruixue Zhang ◽

Liang Yong ◽

Shirui Chen ◽

Hui Zhang ◽

...

Keyword(s):

Missense Mutation ◽

Sequence Alignment ◽

Multiple Sequence Alignment ◽

Molecular Genetic ◽

Family Members ◽

Clinical Manifestations ◽

Gene Mutations ◽

Mendelian Inheritance ◽

Chinese Family ◽

Multiple Sequence

Abstract Background Dyschromatosis universalis hereditaria (DUH) is a pigmentary dermatosis characterized by generalized mottled macules with hypopigmention and hyperpigmention. ABCB6 and SASH1 are recently reported pathogenic genes related to DUH, and the aim of this study was to identify the causative mutations in a Chinese family with DUH. Methods Sanger sequencing was performed to investigate the clinical manifestation and molecular genetic basis of these familial cases of DUH, bioinformatics tools and multiple sequence alignment were used to analyse the pathogenicity of mutations. Results A novel missense mutation, c.1529G>A, in the SASH1 gene was identified, and this mutation was not found in the National Center for Biotechnology Information Database of Short Genetic Variation, Online Mendelian Inheritance in Man, ClinVar, or 1000 Genomes Project databases. All in silico predictors suggested that the observed substitution mutation was deleterious. Furthermore, multiple sequence alignment of SASH1 revealed that the p.S510N mutation was highly conserved during evolution. In addition, we reviewed the previously reported DUH-related gene mutations in SASH1 and ABCB6. Conclusion Although the affected family members had identical mutations, differences in the clinical manifestations of these family members were observed, which reveals the complexity of the phenotype-influencing factors in DUH. Our findings reveal the mutation responsible for DUH in this family and broaden the mutational spectrum of the SASH1 gene.

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One in seven pathogenic variants can be challenging to detect by NGS: an analysis of 450,000 patients with implications for clinical sensitivity and genetic test implementation

Genetics in Medicine ◽

10.1038/s41436-021-01187-w ◽

2021 ◽

Author(s):

Stephen E. Lincoln ◽

Tina Hambuch ◽

Justin M. Zook ◽

Sara L. Bristow ◽

Kathryn Hatchell ◽

...

Keyword(s):

Diagnostic Yield ◽

Copy Number Variants ◽

Low Complexity ◽

Clinical Genetic ◽

Clinical Sensitivity ◽

Pathogenic Variants ◽

Wide Range ◽

Large Indels ◽

Next Generation Sequencing Ngs ◽

The Impact

Abstract Purpose To evaluate the impact of technically challenging variants on the implementation, validation, and diagnostic yield of commonly used clinical genetic tests. Such variants include large indels, small copy-number variants (CNVs), complex alterations, and variants in low-complexity or segmentally duplicated regions. Methods An interlaboratory pilot study used synthetic specimens to assess detection of challenging variant types by various next-generation sequencing (NGS)–based workflows. One well-performing workflow was further validated and used in clinician-ordered testing of more than 450,000 patients. Results In the interlaboratory study, only 2 of 13 challenging variants were detected by all 10 workflows, and just 3 workflows detected all 13. Limitations were also observed among 11 less-challenging indels. In clinical testing, 21.6% of patients carried one or more pathogenic variants, of which 13.8% (17,561) were classified as technically challenging. These variants were of diverse types, affecting 556 of 1,217 genes across hereditary cancer, cardiovascular, neurological, pediatric, reproductive carrier screening, and other indicated tests. Conclusion The analytic and clinical sensitivity of NGS workflows can vary considerably, particularly for prevalent, technically challenging variants. This can have important implications for the design and validation of tests (by laboratories) and the selection of tests (by clinicians) for a wide range of clinical indications.

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One4Two®: An Integrated Molecular Approach to Optimize Infertile Couples’ Journey

Genes ◽

10.3390/genes12010060 ◽

2021 ◽

Vol 12 (1) ◽

pp. 60

Author(s):

Valeria D’Argenio ◽

Federica Cariati ◽

Rossella Tomaiuolo

Keyword(s):

Disease Genes ◽

Diagnostic Efficacy ◽

Whole Process ◽

Pathogenic Variants ◽

Limiting Step ◽

Number Of Genes ◽

Infertile Couples ◽

Next Generation Sequencing Ngs ◽

And Diffusion ◽

Generation Sequencing

The current diagnostic path of infertile couples is long lasting and often ineffective. Genetic tests, in particular, appear as a limiting step due to their jeopardized use on one side, and to the limited number of genes evaluated on the other. In this context, the development and diffusion, also in routine diagnostic settings, of next generation sequencing (NGS)-based methods for the analyses of several genes in multiple subjects at a time is improving the diagnostic sensitivity of molecular analyses. Thus, we developed One4Two®, a custom NGS panel to optimize the diagnostic journey of infertile couples. The panel validation was carried out in three steps analyzing a total of 83 subjects. Interestingly, all the previously identified variants were confirmed, assessing the analytic sensitivity of the method. Moreover, additional pathogenic variants have been identified underlying the diagnostic efficacy of the proposed method. One4Two® allows the simultaneous analysis of infertility-related genes, disease-genes of common inherited diseases, and of polymorphisms related to therapy outcome. Thus, One4Two® is able to improve the diagnostic journey of infertile couples by simplifying the whole process not only for patients, but also for laboratories and reproduction specialists moving toward an even more personalized medicine.

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