Normal & Abnormal Development Flashcards
Genetic disease
A disease that occurs primarily from a genetic abnormality
Inherited
Caused by an inherited genetic abnormality
Acquired
Caused by non-genetic environmental factors
Single gene disorder
-abnormality of a single gene causes disease
-classified as dominant or recessive
-classified as autosomal or sex-linked
Dominant single gene disorder
Dominant single gene disorders will produce the disease where there is only one copy of the abnormal gene
Recessive single gene disorder
Recessive single gene disorders will only be expressed if both copies of the gene are abnormal
Example of a single gene disorder
Sickle cell anaemia
What is the difference between an autosomal disorder and a sex-linked disorder?
-sex-linked inheritance occurs via the genes located on sex chromosomes
-autosomal inheritance occurs via the genes located on autosomes
What is sickle cell anaemia?
-single gene disorder
-caused by a point mutation in the beta-globin chain of haemoglobin
-produces an abnormal haemoglobin which causes erythrocytes to deform when O2 saturation is low
Polygenic gene disorder
A genetic disease which is the result of the interaction of several different genes (usually on different chromosomes)
Breast cancer as a polygenic gene disorder
-genes BRCA1 & BRCA2 have a large individual effect on breast cancer
-most of breast cancer risk is composed of incremental rises in risks by 10s-100s of apparently unrelated genes even when there is a strong family history
Congenital disease
-a disease someone is born with
-congenital diseases will be genetic but can also be acquired (occurs after birth) - this is often by a disease which is due to environmental factors but it may have a strong genetic background
Hypertrophy
Increase in size of a tissue caused by an increase in SIZE of the constituent cells
Hyperplasia
Increase in size of a tissue caused by an increase in NUMBER of the constituent cells
