What is a multifactorial disease?

What is a multifactorial disease?

ABSTRACT: Multifactorial diseases are the result of complex interactions between genetic and environmental factors, thus they are also called complex diseases . The complex phenotypes of multifactorial disorders can be described into two broad categories.

What is the difference between multifactorial inheritance and polygenic inheritance?

The effects of those genes are cumulative, that is, no gene is considered to be dominant or recessive to another. On the other hand, multifactorial inheritance describes a trait whose manifestations are determined by two or more genes, accompanied by environmental factors.

What is polygenic inheritance?

Many characteristics of living beings are influenced by multiple genes. In such cases the characters, instead of being clearly marked, manifest continuous variations between two extremes. This phenomenon is sometimes called character fusion or quantitative inheritance .

What is a Polygenic disease?

These diseases can be defined into two main groups: those that affect just one gene and those that affect several. When only one gene is altered, we say it is a monogenetic disease; when more than one gene has been affected, we say they are multifactorial diseases , also called polygenic .

What are multifactorial characteristics?

The inheritance of semi-continuous or quasi-continuous characteristics is called multifactorial , since such characteristics have variable environmental influence and are determined by several genes. It is also called complex inheritance, due to the complex interactions between several genetic and environmental factors.

What are multifactorial diseases?

Multifactorial : or Polygenic When more than one gene is affected, interference from environmental factors may occur. We can highlight in this group diseases such as Cancer, Alzheimer’s disease, heart disease and hypertension, among others.

How are genetic diseases classified?

Currently, genetic diseases are classified into three types: Monogenetic: Also called Mendelian diseases . These are diseases in which only one gene is modified and , in most cases, they are hereditary; Polygenic: Also called multifactorial diseases .

What are Genetic diseases?

The main genetic diseases in humans are :

  • Down’s syndrome. Down syndrome is a genetic disorder caused by the presence of an extra chromosome in pair 21. …
  • Sickle cell anemia. …
  • Diabetes. …
  • Cancer. …
  • Color blindness. …
  • Duchene muscular dystrophy. …
  • Cystic fibrosis. …
  • Patau syndrome.


What are hereditary and genetic diseases?

As we have already said, genetic diseases are diseases caused by genetic mutation . This means that due to some factor – stress, poor diet, infections, radiation, etc. – the DNA has been modified or damaged, causing the disease to begin. Hereditary diseases are those transmitted between generations.

What are the main hereditary diseases?

What are the main hereditary diseases ?

  1. Obesity. Obesity is one of the most common hereditary diseases in our society, and is characterized by an increase in fat in the body — generally caused by the consumption of excess calories in food. …
  2. Hemophilia A. …
  3. Sickle Cell Anemia. …
  4. Cancer. …
  5. Diabetes. …
  6. Hypertension.


What are recessive diseases?

Examples of autosomal recessive diseases include phenylketonuria, cystic fibrosis and sickle cell anemia. How are recessive diseases inherited?

What is an autosomal recessive disease?

An autosomal recessive disease is characterized by affecting men and women in the same proportion and induced by the recessive gene originating from the crossing of the individual’s parents. The disease only manifests itself if there are 2 recessive alleles .

What are the autosomal dominant diseases?

This type of inheritance is called autosomal dominant inheritance . It is characteristic of SCAs, Huntington’s disease , Myotonic Dystrophy, Familial Amyloidotic Polyneuropathy and many other diseases , each caused by a specific gene.

What is an autosomal dominant disease?

Autosomal means the presence of a pair of genes on a pair of chromosomes other than the one that determines sex, therefore both female and male individuals may be affected.

What is the difference between Autosomal recessive and dominant?

An inheritance is said to be recessive when a certain characteristic is only expressed in homozygosity, that is, an allele alone is not capable of expressing a certain characteristic. We say that an inheritance is dominant when only one of the alleles is sufficient to manifest that characteristic.

What is a dominant gene?

Dominant genes are those that determine a hereditary characteristic even when in a single dose in the genotype. That is, they determine their character even in the absence of their dominant allele . They are classified as: Homozygous Dominant (pure), represented by the capital letters, AA, BB, VV.

What is autosomal dominant inheritance, is it X-linked and what are its characteristics?

Genes located on the X chromosome that have a corresponding allele on the Y chromosome follow the sex- linked inheritance pattern . … Thus, sex- linked inheritance is restricted to sex chromosomes. While, autosomal inheritance is what occurs in autosomal chromosomes .

What difference between sex-linked diseases is restricted to sex?

Sex-linked inheritance refers to part of the X chromosome not homologous to Y. Sex – restricted inheritance refers to part of the Y chromosome not homologous to The father will donate the Y chromosome to determine his sex .

What is Dutch heritage?

Holandric inheritance , linked to the Y chromosome, or sex-restricted inheritance . The Y chromosome has some genes that are exclusive to it, in the curved portion that is not homologous to the X. These genes, also known as holandric genes, characterize the so-called sex-restricted inheritance .

What inheritance patterns should be observed in a Y-linked trait?

That’s why we say that women are the homogametic sex and men are the heterogametic sex. … The genes located in the region of the X chromosome, which does not have homology in Y , follow an inheritance pattern called X- linked inheritance or sex- linked inheritance .

Why in inheritance linked to Y chromosomes only the man can pass the inheritance to his son?

The man , in turn, can pass the defective gene only to his daughter, as he donates only the X chromosome to his daughter . As the man has XY chromosomes , at the time of fertilization, to generate a boy, he will be responsible for providing the chromosome Y , which does not have the characteristics linked to the X chromosome .

How does Y-linked inheritance happen?

Y – linked or sex-restricted inheritance This is mainly due to a gene called SRY (“sex-determining region of Y ”). SRY is found only on the Y chromosome and encodes a protein that activates other genes necessary for male development. Thus, XX embryos do not have SRY and become female.

How many sex chromosomes can be found in a sperm?

The Y chromosome is one of the chromosomes responsible for sex determination. Human sex cells (the egg and sperm ) typically have 23 chromosomes each. In each set of 23 pairs of chromosomes , humans have a pair of chromosomes responsible for sex.

What is color blindness and what is the inheritance pattern for this disease?

Color blindness is a type of inheritance linked to the X chromosome. It occurs more frequently in males and, most of the time, alters the perception of red and green colors.

What does the SRY gene do?

The SRY gene acts as an inducer in male sexual determination. Its expression in somatic cells of the genital crest precedes the first signs of testicular development.

What happens if there is a mutation in SRY?

Mutations in this gene are the cause of several disorders related to the development of the genitals and male sexual characteristics, such as: Androgen insensitivity syndrome: it can be caused by a defect in the part of this gene responsible for androgen receptors (such as testosterone).

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