Genetic and Congenital Disorders CH. 5

Vocabulary flashcards covering key terms related to genetic and congenital disorders, chromosomal aberrations, single-gene inheritance patterns, and teratogenic infectious agents.

Euploid Cells

Cells that have a multiple of the normal number of chromosomes, including haploid and diploid forms.

Polyploid Cells

Euploid cells that possess more than the diploid number of chromosomes.

Triploidy

A form of polyploidy where a zygote has three copies of each chromosome.

Tetraploidy

A condition in which a zygote has four copies of each chromosome, totaling $92$ chromosomes.

Aneuploidy

A condition where a somatic cell does not contain an exact multiple of $23$ chromosomes.

Trisomy

A specific type of aneuploidy in which a cell contains three copies of one chromosome.

Monosomy

The presence of only one copy of any chromosome in a cell, which is often fatal.

Nondisjunction

The failure of homologous chromosomes or sister chromatids to separate normally during meiosis or mitosis, usually causing aneuploidy.

Chromosomal Mosaics

Trisomies that occur in only some cells of the body, creating two or more distinct cell lines each with a different karyotype.

Partial Trisomy

A chromosomal alteration where only an extra portion of a chromosome is present in each cell, resulting in less severe effects than complete trisomy.

Down Syndrome (Trisomy 21)

An autosomal aneuploidy occurring in $1:800$ live births, characterized by mental challenges, a low nasal bridge, epicanthal folds, a protruding tongue, short stature, and poor muscle tone.

Turner Syndrome

A sex chromosome aneuploidy in females having a single X chromosome, characterized by short stature (around $$4'7

Klinefelter Syndrome

A sex chromosome aneuploidy in individuals with male appearance having at least two X chromosomes and a Y chromosome, characterized by long limbs, gynecomastia, sparse body hair, small testes, and inability to produce sperm.

Cri Du Chat Syndrome

A genetic condition resulting from the deletion of the short arm of chromosome 5 ($5p^{-}$), named for its distinctive cat-like cry and marked by low birth weight, severe mental challenge, microcephaly, and heart defects.

Fragile X Syndrome

A fragile site disorder involving a microscopic break on the long arm of the X chromosome, causing severe cognitive impairment; it is the second most common genetic cause of mental retardation after Down syndrome.

Autosomal Dominant Inheritance

A pattern of single-gene inheritance where the abnormal allele is dominant on an autosome, expressing equally in males and females without skipping generations.

Achondroplasia

An autosomal dominant disorder causing dwarfism, characterized by short limbs, fatty skin folds, a low nasal bridge, and a prominent forehead.

Neurofibromatosis

An autosomal dominant disorder (von Recklinghausen disease) involving a tumor suppressor gene that causes variable expressions such as dark skin spots, malignant neurofibromas, scoliosis, gliomas, and neuromas.

Autosomal Recessive Disorders

Genetic disorders caused by recessive abnormal alleles on autosomes, requiring homozygosity for disease expression and typically appearing in siblings rather than parents.

Cystic Fibrosis

An autosomal recessive disorder caused by defective chloride channel transport, leading to salt imbalance and abnormally thick, dehydrated mucus that severely impacts the lungs and pancreas.

Consanguinity

The mating of biologically related individuals (inbreeding), which significantly increases the recurrence risk of autosomal recessive conditions in offspring.

Hemophilia A

An X-linked recessive bleeding disorder caused by a congenital deficiency of Factor VIII, also known as classic hemophilia.

Hemophilia B

An X-linked recessive bleeding disorder caused by a congenital deficiency of Factor IX, also referred to as Royal's Disease.

TORCH Infections

An acronym for teratogenic infectious agents during pregnancy: Toxoplasmosis, Other, Rubella, Cytomegalovirus, and Herpes.