Large Genomic Changes Flashcards
Incidence of down syndrome increases
As maternal age rises
Facial characteristics of down syndrome
Epicanthal folds
Flat nasal bride
3 FAS symptoms
Upturned nose
Type 1 epicantah lfold
Full exposure…no fold in this type
Type 2 epicanthal fold
Partially covers lacrimal lake…joins skin at margin of lacrimal lake
Type 3 epicanthal fold
Lake and caruncle covered almost completely…round medial papebral fissures…lower lid curves to blend in with lower skin
Type 4 epicnathal fold
Reversed epicnathal fold…originates from lwoer eyelid and blends in with upper eyelid skin
Toes - down syndrome
Larger gap between big toes and other four toes
Down syndrome pathology to brain and lens
Increased APP gene dosage…increase aBeta peptide…
In brain, increased Abeta accumulation leads to neuropathology and defects
In lens, increased ABeta leads to protein aggregation, which causes light scattering, leads to supranuclear cataracts
Edwards Syndrome…what does it affect?
Trisomy 18
Kidney, heart, CNS
Prognosis of Edwards syndrome
Most die in utero
How Edwards diagnosed
US, or via alpha-fetoprotein
Quad screening test evaluates which 4 things
AFP, uE3, HCG, DIA
Quad screening not definitive for
Trisomy 13
Chromosome number diseases typically result of
Non-disjunction of chromosomes during meiosis 2
Edwards syndrome presentation
Small head No eyebrows Malformed ears Cleft palate Clenched hands and polydactyly Testes undescended
Klinefelter syndrome
47, XXy
Males with extra X
Turneer syndrome
45, X
Lack an X (barr body)0
Management of Turner Syndrome
Specialty follow-up
Growht hormone therapy
Estrogen replacement to prevent bone degradation and encourage feminizaqtion
Turner syndrome symptoms
Neck skin folds (surgery)
Less developed breats and ovaries
Klinefelter syndrome breast effect
Gynecomastia…will have glandular tissue on breast…can have liposuction
Klinefelter syndrome tx
Testosterone supplementation
Klinefelter syndrome reporudction
Cannot father by natural means…can isolate sperm via other means
2 major types of chromosomal translocation events
Reciprocal and robertsonian
What kind of translocations are philadelphia chromosome and Burkett’s lymphoma?
Reciprocal
Reciprocal vs robertsonian translocation
Reciprocal - between non-homologous chromosomes
Robertsonian - fusion of long arms of two chromosomes
Quad screening test - Downsyndrome
AFP and uE3 down
HCG and DIA up
Quad screening test - Edwards
All down
Quad screening test - Patau
Non conclusive but AFP down
NTD, omphalocele, gastroschisis, multiple gestation - Quad screening test
AFP increase
