Refining the mutational spectrum and gene-phenotype correlates in pontocerebellar hypoplasia: results of a multicentric study.

BACKGROUND: Pontocerebellar hypoplasias (PCH) comprise a group of genetically heterogeneous disorders characterised by concurrent hypoplasia of the pons and the cerebellum and variable clinical and imaging features. The current classification includes 13 subtypes, with ~20 known causative genes. Attempts have been made to delineate the phenotypic spectrum associated to specific PCH genes, yet clinical and neuroradiological features are not consistent across studies, making it difficult to define gene-specific outcomes. METHODS: We performed deep clinical and imaging phenotyping in 56 probands with a neuroradiological diagnosis of PCH, who underwent NGS-based panel sequencing of PCH genes and MLPA for CASK rearrangements. Next, we conducted a phenotype-based unsupervised hierarchical cluster analysis to investigate associations between genes and specific phenotypic clusters. RESULTS: A genetic diagnosis was obtained in 43 probands (77%). The most common causative gene was CASK, which accounted for nearly half cases (45%) and was mutated in females and occasionally in males. The European founder mutation p.Ala307Ser in TSEN54 and pathogenic variants in EXOSC3 accounted for 18% and 9% of cases, respectively. VLDLR, TOE1 and RARS2 were mutated in single patients. We were able to confirm only few previously reported associations, including jitteriness and clonus with TSEN54 and lower motor neuron signs with EXOSC3. When considering multiple features simultaneously, a clear association with a phenotypic cluster only emerged for EXOSC3. CONCLUSION: CASK represents the major PCH causative gene in Italy. Phenotypic variability associated with the most common genetic causes of PCH is wider than previously thought, with marked overlap between CASK and TSEN54-associated disorders.

Sperm Count and Hypogonadism as Markers of General Male Health.

BACKGROUND: Some evidence suggests that infertile men, who are at increased risk for hypogonadism, metabolic derangements, and osteoporosis, have higher long-term morbidity and mortality than controls, but data are scarce and not conclusive. OBJECTIVE: We tested whether semen quality and reproductive function could represent a marker of general male health. DESIGN, SETTING, AND PARTICIPANTS: A retrospective study of 5177 individuals from a prospectively collected database of 11516 males of infertile couples who had semen analysis in a tertiary university center. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Of them, 5177 had all data for reproductive hormones, testis ultrasound, and biochemical determinations for glucose and lipid metabolism. Hypogonadism was defined as testosterone <10.5nmol/l and/or luteinizing hormone >9.4 IU/l. Individuals with a total sperm count of <10 million had genetic testing (karyotype, Y chromosome microdeletions, and CFTR gene mutations) and those with hypogonadism underwent dual-energy x-ray absorptiometry for bone mineral density. Descriptive statistics and odds ratio (OR) calculation were used. RESULTS AND LIMITATIONS: Men with a low sperm count (<39 million/ejaculate) are at a high risk of hypogonadism (OR 12.2, 95% confidence interval [CI] 10.2-14.6) and have higher body mass index, waist circumference, systolic pressure, low-density lipoprotein cholesterol, triglycerides, and homeostatic model assessment (HOMA) index; lower high-density lipoprotein cholesterol; and a higher prevalence of metabolic syndrome (OR 1.246, 95 CI 1.005-1.545). All data are worse in men with hypogonadism, but a low sperm count per se is associated with a poor metabolic parameter. Men with hypogonadism have lower bone mineral density and 51% prevalence of osteoporosis/osteopenia. Longitudinal studies are necessary to support these data. CONCLUSIONS: This is the largest study with comprehensive evaluation of semen quality and reproductive function, etiology and risk factor determination, and metabolic, cardiovascular, and osteoporosis risk assessment, performed in men referred for fertility evaluation. A low sperm count is associated with poorer metabolic, cardiovascular, and bone health. Hypogonadism is mainly involved in this association, but a low sperm count in itself is a marker of general health. PATIENT SUMMARY: This large study evaluated semen quality, reproductive function, and metabolic risk in men referred for fertility evaluation, and showed that a man's semen count is a marker of his general health. Men with low sperm counts are more likely than those with normal sperm counts to have greater body fat, higher blood pressure, higher "bad" (low-density lipoprotein) cholesterol and triglycerides, and lower "good" (high-density lipoprotein) cholesterol. They also have a higher frequency of metabolic syndrome and insulin resistance, a condition that can lead to diabetes. Men with low sperm counts had a 12-fold increased risk of hypogonadism or low testosterone levels, and half of them had osteoporosis or low bone mass. Fertility evaluation gives men the unique opportunity for health assessment and disease prevention.

Contemporary genetics-based diagnostics of male infertility.

Introduction Thousands of genes are implicated in spermatogenesis, testicular development and endocrine regulation of testicular function. The genetic contribution to male infertility is therefore considerable, and basic and clinical research in the last years found a number of genes that could potentially be used in clinical practice. Research has also been pushed by new technologies for genetic analysis. However, genetic analyses currently recommended in standard clinical practice are still relatively few. Areas covered We review the genetic causes of male infertility, distinguishing those already approved for routine clinical application from those that are still not supported by adequate clinical studies or those responsible for very rare cause of male infertility. Genetic causes of male infertility vary from chromosomal abnormalities to copy number variations (CNVs), to single-gene mutations. Expert opinion Clinically, the most important aspect is related to the correct identification of subjects to be tested and the right application of genetic tests based on clear clinical data. A correct application of available genetic tests in the different forms of male infertility allows receiving a better and defined diagnosis, has an important role in clinical decision (treatment, prognosis), and allows appropriate genetic counseling especially in cases that should undergo assisted reproduction techniques.

Molecular Bases of Sperm Thermotaxis: Old and New Knowledges.

Sperm thermotaxis, namely the temperature-oriented motility of sperm cells, is a key process involved in ejaculated sperm guidance towards the oocyte for fertilization pourposes. Since its discovery in 2003, many studies clarified the dynamics, the sensitivity and the overall weight of this process in the comprehensive context of fertilization. However, the identification of sperm thermosensor/ s remained elusive until recently. The most recent cues about the molecular bases of the old known process of thermotaxis are here revised. Moreover, the possible pathophysiological and therapeutic repercussions deriving from the widening of this process are also discussed.

New Markers for Predicting Fertility of the Male Gametes in the Post Genomic Era.

A number of tests have been proposed to assess male fertility potential, ranging from routine testing by light microscopic method for evaluating semen samples, to screening test for DNA integrity aimed to look at sperm chromatin abnormalities. Spermatozoa are an extremely differentiated cell population, having critical functions for embryo development and heredity, apart from giving haploid paternal DNA to the oocyte. Some aspects are essential to set this specific purpose. The ability of spermatozoa to perform its reproductive function takes place in the spermatogenesis, a highly specialized process depending on multiple factors with effect on male fertility. In the past 30 years, large-scale analyses of transcriptomic and proteomic analyses in mammals have generated a large amount of information on numerous biomolecules involved in spermatogenesis and male germ cell reproductive function. Sperm proteome represents the protein content that spermatozoa needs to survive and work correctly and modifications of sperm proteome play a role in determining functional changes leading to a decrease of reproductive competence into affected spermatozoa. The post-genomic approach consists of different methodologies for concurrently testicular transcriptome studies, protein compositional analysis and metabolomics findings of the spermatozoa in humans.

Lactase non-persistent genotype distribution in Italy.

BACKGROUND: Adult-type hypolactasia is a frequent condition of lactose malabsorption; in Europe the distribution of adult-type hypolactasia have been shown to display a North-South gradient. Genotyping for LCT-13910 C>T polymorphism has been proposed as a useful diagnostic marker of adult-type hypolactasia. Data concerning lactase non-persistent genotype distribution in Italy are confused and not well characterized. The aim of this study was to determine the prevalence of CC-genotype corresponding to lactase non-persistence in Italian population. METHODS: We genotyped 1312 adult Italian subjects for LCT-13910 C>T polymorphism by KASPar chemistry (KBioscience Ltd., Hoddesdon, England, UK). RESULTS: The frequency of the lactase non-persistence genotype of our sample was 62.3% that was higher than the values published for adult hypolactasia in Italy. In our study a frequency of 58.6%, 74.1% and 67.1% was detected in the three main macro-regions of Italy (North, Center, and South), respectively. CONCLUSIONS: For the first time we analyzed the distribution of the LCT-13910 CC genotype in a big population of Italian subjects. Our data did not validate the presence of a North-South gradient for adult hypolactasia along the Italian peninsula.

Is there any clinical relevant difference between non mosaic Klinefelter Syndrome patients with or without Androgen Receptor variations?

Klinefelter Syndrome (KS) is the most common chromosomal disorder in men leading to non-obstructive azoospermia. Spermatozoa can be found by TESE in about 50% of adults with KS despite severe testicular degeneration. We evaluated AR variations and polymorphism length in 135 non-mosaic KS patients, aimed to find possible correlation with clinical features, sex hormones and sperm retrieval. Among 135 KS patients we found AR variations in eight subjects (5.9%). All variations but one caused a single amino acid substitution. Four variations P392S, Q58L, L548F, A475V found in six patients had been previously described to be associated with different degrees of androgen insensitivity. Moreover we observed in two patients Y359F and D732D novel variations representing respectively a missense variation and a synonymous variation not leading to amino acid substitution. All the Klinefelter patients with AR gene variations were azoospermic. Spermatozoa were retrieved with TESE for two men (40%), sperm retrieval was unsuccessful in other 3 patients. This is the only study reporting AR variations in KS patients. Relevant clinical differences not emerged between AR mutated and not AR mutated KS patients, but does each variation play an important role in the trasmission to the offspring obtained by ART in this patients?

CTNND2 deletion and intellectual disability.

Neurodevelopmental disorders are a group of diseases characterized by either structural or functional alterations. The clinical spectrum can vary from isolated intellectual disability to more complex syndromes. Molecular karyotyping can explain 14%-18% of cases due to the presence of large pathogenic CNVs. Moreover, small CNVs involving single genes might result in a monogenic disease. In this article we report two cases of intragenic CTNND2 deletion, detected by molecular karyotyping, in patients with isolated intellectual disability.

Next generation sequencing in nonsyndromic intellectual disability: from a negative molecular karyotype to a possible causative mutation detection.

The identification of causes underlying intellectual disability (ID) is one of the most demanding challenges for clinical Geneticists and Researchers. Despite molecular diagnostics improvements, the vast majority of patients still remain without genetic diagnosis. Here, we report the results obtained using Whole Exome and Target Sequencing on nine patients affected by isolated ID without pathological copy number variations, which were accurately selected from an initial cohort of 236 patients. Three patterns of inheritance were used to search for: (1) de novo, (2) X-linked, and (3) autosomal recessive variants. In three of the nine proband-parent trios analyzed, we identified and validated two de novo and one X-linked potentially causative mutations located in three ID-related genes. We proposed three genes as ID candidate, carrying one de novo and three X-linked mutations. Overall, this systematic proband-parent trio approach using next generation sequencing could explain a consistent percentage of patients with isolated ID, thus increasing our knowledge on the molecular bases of this disease and opening new perspectives for a better diagnosis, counseling, and treatment.