3: Genetic Disorders

GENETIC DISORDERS

health problems that happen because of some type of abnormality in a person's genetic material

genetic disorders

not all __ can be detected by a karyotype

KARYOTYPE

an individual's collection of chromosomes

KARYOTYPE

also refers to a laboratory technique that produces an image of an individual's chromosomes

karyotypes

it can only see the number and structure of chromosomes, they cannot determine if it's heterozygous or homozygous

aneuploidy

nondisjunction

NUMERICAL MUTATIONS

ANEUPLOIDY

a condition where there is an addition or deletion of one or more chromosomes

ANEUPLOIDY

in certain chromosome pairs can result in the survival of an offspring, but with severe abnormalities or developmental difficulties (however, it can be disruptive to the extent it can kill the embryo)

trisomy and monosomy

types of aneuplody

NONDISJUNCTION

is the failure of a pair of homologous chromosomes or a pair of sister chromatids to separate during mitosis or meiosis

Down syndrome (trisomy 21)

Patau syndrome (trisomy 13)

Edward Syndrome (trisomy 18)

Klinefelter Syndrome (XXY)

Turner Syndrome (XO)

Jacob Syndrome (XYY)

Trisomy X Syndrome (XXX)

types of nondisjunction

Down syndrome

trisomy 21

Patau syndrome

trisomy 13

Edward Syndrome

trisomy 18

Klinefelter Syndrome

XXY

Turner Syndrome

XO

Jacob Syndrome

XYY

Trisomy X Syndrome

XXX

STRUCTURAL MUTATIONS

alterations that affect whole chromosomes and whole genes rather than just individual nucleotides

STRUCTURAL MUTATIONS

these mutations result from errors in cell division that cause a section of a chromosome to break off, be duplicated, or move onto another chromosome

Translocation

Inversion

Deletion

Duplication

STRUCTURAL MUTATIONS

Translocation

the transfer of genetic material between two non-homologous chromosomes

Translocation

the common form involves a single break in each of the two chromosomes and an exchange of the broken pieces

Myeloid leukemia

Translocation disease

Inversion

the sequence of a gene (orientation) changed which involves two breaks in a chromosome, followed by the broken ends reattaching in reverse order

Inversion

the change in arrangement of genes may result in phenotypic changes that are usually not damaging

paracentric and pericentric

two types of inversions

Paracentric

both breaks occur in one arm of the chromosome

Pericentric

the centromere is involved, and each arm has a breakpoint

Deletion

breaks in a chromosome > deleted genetic material > shorter chromosome

Deletion

usually caused by breaks in a way chromosome and a consequent loss of one or more genes and the effects increase as more genes get deleted

Cri-du-chat

- deletion in chromosome 5

deletion disease

Duplication

a part of a chromosome is duplicated, or present in 2 copies

Duplication

these extra instructions can lead to errors in the development of a baby