Inherited Disorders

3 Key excerpts on "Inherited Disorders"

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  eBook - ePub

  Diagnostics and Gene Therapy for Human Genetic Disorders

  • K.V. Chaitanya(Author)
  • 2022(Publication Date)
  • CRC Press

    (Publisher)

  3 Genetic Disorders

  DOI: 10.1201/9781003343790-3

  3.1 Introduction

  Human genome sequencing and its annotation have rapidly increased the knowledge of genetic disease. We can mark the traditional category of genetic diseases with a specific genetic contribution through the human genome, facilitating a list of diseases contributed by genes and the environment. Future genomics knowledge makes a significant contribution to the rapid diagnosis of genetic diseases. All humans are at risk of acquiring these genetic diseases due to exposure to mutagens and radiation, which lead to a high rate of genetic mutations. The high prevalence of these genetic diseases, particularly in specific communities is also due to social and cultural factors, such as consanguineous marriage, resulting in a high rate of autosomal recessive conditions including congenital malformations, stillbirths, and mental retardation. Further, maternal age above 35 years is associated with a high frequency of chromosomal abnormalities in the offspring.

  A genetic disease can vary in severity from being lethal right before birth to requiring continuous monitoring and support during all stages of human life. Genetic disease at birth is a severe burden leading to early death or lifelong chronic morbidity. Around 8 million children are born globally per year with severe genetic malformations. Among them, 90% of the infants are born in mid or low-income countries, and the data in the developing countries is uncertain primarily because of the genetic diversity and non-diagnosis of genetic diseases. In developed countries, genetic and congenital disorders are the second most common reason for infant death, occurring at the rate of 25 - 60 per 1000 births. The current chapter focuses on the main reasons for genetic disorders and their classification.

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  Developmental Psychology

  • Amanda Ludlow, Roberto Gutierrez(Authors)
  • 2014(Publication Date)
  • Bloomsbury Academic

    (Publisher)

  Genetic influence on cognitive abilities reveals a steady increase in the heritability of general cognitive ability from childhood through adulthood (Haworth et al., 2010). 60 Developmental Psychology Genetic abnormalities It is not uncommon for genetic abnormalities to occur, when a sperm or ovum is formed the number of chromosomes may divide unevenly resulting in more or less than the normal 23 chromosomes, in some cases, about one in every 200 live births. The majority of neurodevelop-mental disorders are caused by genetic abnormalities. A genetic disorder is an illness caused by abnormalities in genes or chromosomes, which are often present before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions. A genetic disorder may be caused by an inherited genetic condition in some people, by new mutations in other people, and by non-genetic causes in still other people. Genes contain the information used by other parts of a cell to make proteins. Proteins are the body’s building blocks. Each protein performs a specific job. They make up the structure of your organs and tissues and are needed for all of your body’s chemical functions. Each gene contains information for making at least one protein. If this information is changed, then the cell may not be able to make that protein, or it may not be able to make a form of the protein that the body can use. There are four main genetic types of neurodevelopmental disorders. Types of neurodevelopmental disorders 1 Disorders that result from mutations in a single gene . Examples are , phenylketonuria and fragile X syndrome . Fragile X occurs because the FMR1 gene is unable to make normal amounts of usable Fragile X Mental Retardation Protein, or FMRP. 2 Chromosomal disorders in which an entire chromosome is missing or deleted. Examples are Down syndrome or Turner syndrome . Down syndrome occurs when there is an extra copy of chromosome 21.

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  The Genetic Gods

  Evolution and Belief in Human Affairs

  • John C. Avise(Author)
  • 2009(Publication Date)
  • Harvard University Press

    (Publisher)

  Instead, some afºictions resulted from endogenous, heritable, mechanistically understandable molecular foul-ups. 3 Sci-entists came to realize that the elaborate metabolic machineries of the human body are subject to heritable design ºaws, sometimes with serious health consequences. With the development and application of biomedical technolo-gies in recent decades, the list of metabolic disorders ascribed to simple genetic defects in humans has grown rapidly (see Figure 3.1). Since the early 1960s, gene catalogues inspired by Garrod’s work have provided growing encyclopedias to these human ge-netic conditions. One of these modern tomes, The Metabolic and Molecular Bases of Inherited Disease (MMBID), occupies nearly 5,000 pages of ªne print detailing the genetics, biochemical bases, and clinical symptoms of approximately ªve hundred single-gene dis-orders in humans. A recent edition of another such compendium, Mendelian Inheritance in Man (MIM), describes more than 6,000 human genes, of which about 75 percent are reported to have mutational defects associated with a disease phenotype. In recent years, MIM has been online and is updated daily by computerized searches of the scientiªc literature. 4 Some hereditary disorders are characterized far better than oth-ers. Alkaptonuria has been studied intensively since Garrod’s early T H E G E N E T I C G O D S 54 research, as evidenced by the sixteen pages devoted to its detailed clinical, biochemical, and genetic description in the 1995 MMBID catalogue. Although a few ªne points of the alkaptonuria defect remain unknown, the gene responsible was localized recently to chromosome 3 in the total human complement of twenty-three chromosomal pairs.

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