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Inborn errors of metabolism

A large class of genetic diseases resulting from congenital disorders of enzyme activities due to defects of single genes that code for enzymes, leading to the accumulation of toxic substances.

Phenylketonuria (PKU)

An inborn error of amino acid metabolism due to an error in the gene for phenylalanine hydroxylase, leading to increased levels of phenylalanine in the blood and severe mental retardation if untreated.

Mendelian inheritance

Principles of inheritance first established by Gregor Mendel, which include the law of segregation, law of dominance, and law of independent assortment.

Allele

Different versions of a gene that can exist at a particular locus, which may be dominant or recessive.

Homozygous

An organism that has two identical alleles for a particular gene.

Heterozygous

An organism that has two different alleles for a particular gene.

Autosomal recessive inheritance

A mode of inheritance where a disease is caused by the absence of an intact gene and requires two copies of the mutated gene for the condition to manifest.

Genetic diversity

Variation in the genetic makeup among individuals within a population, resulting from mutations, gene swapping during meiosis, and random errors in DNA replication.

Karyotype

A visual display of all chromosomes in a cell, used to assess chromosomal abnormalities.

Monogenic disease

A disease caused by a single gene mutation, such as sickle cell anemia and cystic fibrosis.

Polygenic disease

A disease that is caused by the combined effects of multiple genes and often environmental factors, such as diabetes and coronary heart disease.

Congenital metabolic diseases

Another term for inborn errors of metabolism, highlighting their presence at birth and genetic basis.

Cofactor

A non-protein chemical compound that is required for the biological activity of a protein, such as an enzyme.

Mitosis

Normal cell division that occurs throughout life, producing two identical daughter cells.

Meiosis

The process of cell division that produces gametes (egg and sperm), which undergo genetic variation through recombination.

SNP (Single Nucleotide Polymorphism)

A variation in a single nucleotide that occurs at a specific position in the genome, often used as a marker in genetics.

Genetic liability

The susceptibility to genetic conditions due to inherited genetic factors.

Environmental liability

The susceptibility to genetic conditions due to environmental factors.

Phenylalanine restriction

A dietary intervention for individuals with PKU that limits phenylalanine intake to prevent toxic accumulation.

Sickle cell anemia

An autosomal recessive disease that affects red blood cells, causing them to deform and leading to various health complications.

Threshold theory

A concept used to explain polygenic diseases, where a certain threshold of genetic and environmental factors must be exceeded for the disease to manifest.

Gene swapping

The process that occurs during meiosis where chromosomes exchange genetic material, contributing to genetic diversity.

DNA replication

The process of copying the DNA molecule before cell division, where errors can lead to mutations.