Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Testicular aging starts form age 30 with progressive deterioration of vascularization, the density of capillaries, the diminution of the efficacy of the blood-testis barrier, the aging of Sertoli cells, which results in fall of production of androgen-binding protein. These changes lead to a slow reduction of the number of spermatozoa, although it is their quality that is responsible for male fertility. Analysis of the number, morphology, and mobility of spermatozoa of men aged 25-59 showed that the quality varies depending on age: the maximum values are reached between age 25 and 35, decreasing afterwards. The aging finally results in a degradation of the number and especially in the quality of spermatozoa, which is not satisfactory in individuals of very young age either. Whether male of female, parental aging poses a problem, because fertility diminishes and the risk of anomalies of the conceptus increase with the age of parents. It has been demonstrated that the new, autosomal dominant mutations responsible for fetal deaths or the numerous malformation syndromes, such as achondroplasia, Apert's disease, ossifying fibrodysplasia, and Marfan's syndrome, may be linked to paternal aging. The frequency of each of these syndromes is very low: 15-28 cases per million births for achondroplasia. Also, the frequency of anomalies attributable to paternal aging after the 40s reaches .3-.5% of births. Neurofibromatosis or von Recklinghausen's disease, hemophilia A, the myopathy of Duchenne, schizophrenia, and the performance of 18-year-old males on psychometric tests have been associated with paternal aging. The aging of gonads cannot be prevented, but one could avoid the consequences of the aging of gametes by avoiding having children after 35 or 40 years of age. This has been recommended to women for about 15 years, and perhaps should also be recommended to men.
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PMID:[Evolution of male fertility as a function of age and risks in progeny]. 1228 63

Delayed childbearing is a common phenomenon in industrialized countries. This review focuses on age-associated alterations of male fertility and genetic risks. Semen volume, sperm motility and sperm morphology decrease with age, whereas the data concerning sperm concentration are conflicting. The age-related changes of semen parameters reflect the histological modifications which are found to varying degrees in individual testes. Men aged >40 years contribute to reduced fertility and fecundity of a couple, especially when the female partner is also of advanced age. Because relatively few children are born to older fathers and genetic diseases are rare, there is little statistical power supporting an association of genetic diseases in the offspring with advancing paternal age. Nevertheless, autosomal dominant diseases and some diseases of complex aetiology, such as schizophrenia, are associated with advancing paternal age. The single point mutations in sperm which are responsible for achondroplasia and Apert's syndrome, two autosomal dominant diseases, increase with the man's age. In case of Apert's syndrome this increase is believed to be due to a pre-meiotic selection of mutant spermatogonia. Although structural chromosome anomalies and disomies of certain chromosomes increase in sperm with the man's age, paternal age is, with the exception of trisomy 21, not associated with numerical or de novo structural chromosomal aberrations in newborns. However, even if the genetic risk for progeny from older fathers is slightly increased, the risk to the individual is low.
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PMID:Reproductive functions of the ageing male. 1519 59

Advanced paternal age has been associated with an increased risk for spontaneous congenital disorders and common complex diseases (such as some cancers, schizophrenia, and autism), but the mechanisms that mediate this effect have been poorly understood. A small group of disorders, including Apert syndrome (caused by FGFR2 mutations), achondroplasia, and thanatophoric dysplasia (FGFR3), and Costello syndrome (HRAS), which we collectively term "paternal age effect" (PAE) disorders, provides a good model to study the biological and molecular basis of this phenomenon. Recent evidence from direct quantification of PAE mutations in sperm and testes suggests that the common factor in the paternal age effect lies in the dysregulation of spermatogonial cell behavior, an effect mediated molecularly through the growth factor receptor-RAS signal transduction pathway. The data show that PAE mutations, although arising rarely, are positively selected and expand clonally in normal testes through a process akin to oncogenesis. This clonal expansion, which is likely to take place in the testes of all men, leads to the relative enrichment of mutant sperm over time-explaining the observed paternal age effect associated with these disorders-and in rare cases to the formation of testicular tumors. As regulation of RAS and other mediators of cellular proliferation and survival is important in many different biological contexts, for example during tumorigenesis, organ homeostasis and neurogenesis, the consequences of selfish mutations that hijack this process within the testis are likely to extend far beyond congenital skeletal disorders to include complex diseases, such as neurocognitive disorders and cancer predisposition.
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PMID:Paternal age effect mutations and selfish spermatogonial selection: causes and consequences for human disease. 2232 59

There is robust evidence from epidemiological studies that the offspring of older fathers have an increased risk of neurodevelopmental disorders, such as schizophrenia and autism. The authors present a novel mechanism that may contribute to this association. Because the male germ cell undergoes many more cell divisions across the reproductive age range, copy errors taking place in the paternal germline are associated with de novo mutations in the offspring of older men. Recently it has been recognized that somatic mutations in male germ cells that modify proliferation through dysregulation of the RAS protein pathway can lead to within-testis expansion of mutant clonal lines. First identified in association with rare disorders related to paternal age (e.g., Apert syndrome, achondroplasia), this process is known as "selfish spermatogonial selection." This mechanism favors propagation of germ cells carrying pathogenic mutations, increasingly skews the mutational profile of sperm as men age, and enriches de novo mutations in the offspring of older fathers that preferentially affect specific cellular signaling pathways. This mechanism not only offers a parsimonious explanation for the association between advanced paternal age and various neurodevelopmental disorders but also provides insights into the genetic architecture (role of de novo mutations), neurobiological correlates (altered cell cycle), and some epidemiological features of these disorders. The authors outline hypotheses to test this model. Given the secular changes for delayed parenthood in most societies, this hypothesis has important public health implications.
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PMID:"Selfish spermatogonial selection": a novel mechanism for the association between advanced paternal age and neurodevelopmental disorders. 2363 89

Infertility and fecundity problems concern 10-18% of partners in their reproductive years compromising around one million females and males in Poland. Research and analysis of factors that affect male fertility are limited, especially, regarding the age of the father and determining the age at which quality of semen decreases. Age of the father has greater impact than maternal age, on cases of sporadic autosomal dominant congenital diseases such as Apert, Crouzon, Pfeiffer, Noonan and Costello syndromes, multiple endocrine neoplasia (types 2A and 2B) and achondroplasia. However, there are only a few reports taking paternal advanced age into consideration for pre-mature birth, low Apgar scores or admission to a neonatal intensive care department. Paternal age increases the frequency of congenital diseases such as heart malformations as well as oral, palate and lip cleft. Moreover, mental disorders (autism, schizophrenia, bipolar disorder, low IQ level as well as ADHD) also occur more frequently in advanced father's age. Advanced paternal age is defined differently in every research. It depends on disorders in offspring we are talking about. Paternal age has an impact on child's health and development and it is as significant as maternal age, when it comes to reproductive matters.
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PMID:Paternal age is affected by genetic abnormalities, perinatal complications and mental health of the offspring. 3204 16