Genetic Diseases

Down Syndrome

• 1/650 risk, 1/40 with maternal age of 44

• cognitive impairment and 40% congenital heart defect

Trisomy 18, Edward’s Syndrome

• 1/10,000 - 5-10% survive 1 year

• intellectual disability, low birth rate, abnormally shaped head, clenched fists, and heart defects

Trisomy 13, Platau Syndrome

• 80% die within first month

• cleft lip, close-set eyes, low-set ears, poor muscle tone, seizures, deafness, polydactly, intellectual disability, microcephaly

• mosaic: less severe version, 1/10,000

Turner’s Syndrome, 45X0

• 1/2,000 females

• pronounced webbing of the neck, short, ovarian cancer

Triple X Syndrom (XXX)

• 1/1,000 females

• no phenotype, females are still fertile

Lejune Syndrome

• 1/50,000

• characteristic cry, intellectual disability, difficulty swallowing, hyperactive & aggressive, can bear children

Structural Aberrations

deletions, duplications, inversions, and translocations

Inversions

breakage of a chromosome at 2 points and rejoining in wrong orientation

Balanced Translocation

chromosome arms exchange parts, no loss or gain of genetic material

Polydactyly

more than 5 digits on hands and/or feet

Achondroplasia

• dominant mutation within FGFR3 gene 

• short stature and limbs, prominent forehead

Myotonic Dystrophy

autosomal dominant, expanding nucleotide repeat

Myotonia

slow releaxation of muscle after contraction, heart and respiratory problems, cataracts

Marfan Syndrome

• dominant mutation on fibrillin gene

• affects protein product in elastic connective tissue

• long, spindly body, hands, and feet

• life expectancy 40-50

Epidermolysis Buliosa Simplex

autosomal dominant, trauma blistering

AMD

age-related macular degeneration, central retinal blindness