Genetics of Down Syndrome and Turner Syndrome

A condition where there is an abnormal number of chromosomes in a cell, often resulting from errors during cell division. This can involve an extra or missing chromosome (aneuploidy) or an entire extra set of chromosomes (polyploidy).

The failure of chromosomes to separate properly during cell division, leading to an abnormal number of chromosomes in the daughter cells. This can occur during meiosis (gamete formation) or mitosis (regular cell division).

A type of nondisjunction that occurs during meiosis (sex cell division), leading to gametes with an incorrect number of chromosomes. This can result in offspring with chromosomal disorders.

A type of nondisjunction that happens during mitosis (regular cell division), leading to cells with an incorrect number of chromosomes within the organism. This can contribute to the development of certain cancers.

An individual with a normal set of two chromosomes (2n) for each pair.

A condition where an organism possesses one extra set of the entire genome, resulting in three sets of chromosomes (3n).

A condition characterized by the presence of one extra chromosome, resulting in three copies of that chromosome (2n+1).

A condition characterized by the absence of one chromosome, resulting in only one copy of that chromosome (2n-1).

A condition where a portion of chromosome 5 is deleted, resulting in a characteristic cat-like cry in infants.

A change in chromosome structure where a segment is lost.

When a chromosome segment is repeated, leading to an extra copy of genes.

Changes that affect the arrangement of genetic material within a chromosome. Examples include translocations, deletions, duplications, inversions and ring chromosomes.

Occurs when a chromosome breaks and the broken ends rejoin in a reversed order.

A type of chromosomal abnormality where a chromosome loses its ends and forms a ring shape.

A type of chromosomal rearrangement where parts of two non-homologous chromosomes exchange segments.

This refers to conditions where a single copy of a gene is not sufficient to produce a normal phenotype, causing developmental abnormalities.

A condition where an individual possesses an extra copy of chromosome 21.

A type of Down Syndrome where the extra chromosome 21 is attached to another chromosome, often chromosome 14.

The presence of two or more genetically distinct cell lines in an individual.

A chromosomal disorder resulting from the presence of an extra X chromosome in males (XXY), leading to physical and developmental differences.

A chromosomal disorder caused by the absence of one X chromosome in females (X0), resulting in various physical and developmental features.

The process by which one of the two X chromosomes in females is inactivated to equalize the expression of X-linked genes with males.

A genetic disorder characterized by the presence of only one X chromosome in females (XO), leading to various physical and developmental features. It is often associated with short stature, infertility, and sometimes heart defects.

A genetic condition in males with an extra Y chromosome (47,XYY).

A genetic condition in females with an extra X chromosome (47,XXX).

The 23rd pair of chromosomes that determine an individual's sex.

A process where the expression of a gene depends on its parent of origin. It means a gene's expression is determined by whether it was inherited from the mother or father.

A type of chromosome structure anomaly where a segment of a chromosome is lost.

A type of chromosome structure anomaly where a segment of a chromosome is duplicated, leading to an extra copy of those genes.

The alteration of chromatin structure, influencing gene expression. It refers to changes in how tightly DNA is packed, impacting how easily genes are accessed and transcribed.

A genetic disorder where a specific gene is silenced due to imprinting, resulting in developmental delays, severe speech impairment, and characteristic happy demeanor.

A genetic disorder impacting both physical and intellectual development, characterized by poor weight gain in infancy, excessive weight gain later, delayed sexual maturity, and an obsession with food.

A genetic disorder where three copies of chromosome 21 are present instead of the usual two.