Congenital and Hereditary

congenital disease

abnormality present at birth even though it may not be detected until sometime after birth

maternal infections that cause fetal deformities

Toxoplasmosis, other (zika virus), rubella, cytomegalovirus, herpes

monosomy

absence of a chromosome in a cell

trisomy

presence of an extra chromosome

chromosome deletion

chromosome breaks during meiosis, and broken pieces are lost or translocated

translocation

misplaced chromosome attaches to another chromosomes

gene

sequence of DNA that codes for a protein and gives rise to a physical trait

locus

area of chromosome where a gene is located

alleles

alternative forms of a gene found on a maternal and paternal chromosomes

homologous pair

chromosomes from each parent paired together

homozygous

alleles are same

heterozygous

alleles are different

dominant gene

expressed in either homozygous or heterozygous state

Recessive gene

expressed only in homozygous state

codominant gene

both alleles of a pair are expressed

sex linked gene

genes carried on sex chromosome produced sex linked traits

turner syndrome

infertile, webbed neck, low hairline, low ears

triple X syndrome

fertility unaffected, tall, delayed speech, mild intellectual disabilities

Klinefelter syndrome

infertile, large breast, wide hips, minimal body hair

XXY syndrome (Jacobs syndrome)

fertility unaffected, tall, cystic acne, speech delays, behavioral issues

fragile X syndrome

abnormality of X chromosome near tip, major cause of mental deficiency