genetics Flashcards
Downs syndrome usually occurs due to
nondisjunction in Meiosis in the Ovum
(can also occur due to robertsonian translocation)
-advanced maternal age is a risk factor
pts with down’s syndrome at risk for which cancers
AML ALL
acetylation of histones
enhances gene transcription
deacetylation of histones
silences the genes
-in HD, the mt huntington gene enhances the deacetylation of genes
hypermethylation of a transcription gene
leads to gene silencing
neonate with lymphemeda and cystic hygromas
tuners syndrome
t (15,17)
acute promyelocytic leukemia
-PML/RARalpha
M3 varian of AML
-younger pts, on smear see many auer rods, in
t(8,14)
Burkitts lymphoma
-c-myc translocated to immunoglobin gnee
t (9,22)
philadelphia chromosome, CML, bcr-abl
t (11, 14)
mantle cell B lymphoma
-activation of cyclin D gene
situs inversus + recurrent sinopulmonary infections
kartagener syndrome (immotile cilia syndrome)
-due to failure of dyenin arms to develop normally
-causes decreased clearing of epithelial cells
leads to infertility in men and can lead to infertility in women as well due to decreased fallopian tube cilia mobility
-autosomal recessive
neonate with low-set ears, clenched fists, overlapping fingers, micrognathia, microcephaly, arnold chiari, rocker bottom feet, HYPERtonia, VSD, PDA, Meckels, malrotation
Edwards, trisomy 18
-key abnormal hand (clenched with overlapping fingers)
cleft lip/palate, micropthalmia, coloboma, cyclops, deafness, scalp defects, PDA
Patau, trisomy 12
-most die within week and others rarely survive past 6 months,
ataxia, cardiomyopathy, pes cavus, hammer toes, kyphoscoliosis,
Friedrich ataxia
-chromosome 9, increaased trinucleotide repeats
-10% also develop Diabetes mellitus
death usually by cardiomyopathy and/or bulbar dysfunction
multiple telangiectasia of skin and mucosa with recurrent epistaxis
hereditary hemorrhagic telangiectasia (Osler-Rendu-Weber syndrome)
FGFR 3 mutation
achondroplasia (dwarfism)
autosomal dominant, lethan in homozygous dominant
-therfore heterozygous person has 50% chance of having a short kid
ectopia lensis, MR, vascular thromboses, marfanoid, osteoporosis
homocystinuria,
cystathionine beta synthase deficiency
an example of pleiotrophy
increased AFP
increased Ach
Neural tube defects
hypotonia, poor feeding, macroglossia, jaundice, constipation, hoarse cry
congenital hypothyroidism
prevents normal brain devleopment and myelination during early life
-also at higher risk of congenital heart risk (ASD/VSD)
-irreversible mental retardation,
-a normal screening test
chromosome 22 long arm deletion
DiGeorge
CATCH 22
Cleft lip/cardiac anomalies like interrupted aortic arch
Abnormal facies
Thymic hypoplasia-recurrent viral infection due to decreased T cell maturation
Hypocalcemia due to pit abnormalities
t (14,18)
follicular lymphoma (a non-Hodgkin lymphoma)
leading to overexpression of bcl-2–> a proto-oncogene tha tprevents the release of pro-apoptotic factors)
14-immunoglobin heavy chain enhancer
histone located outside of nucleosome core
Histone H1, aid in DNA packing of regions between each core making entire structure more tight
inside (H2A, H2B, H3, H4)X2
genetics of Alzheimer’s
ApoE4 associated with familial late onset AD
Presenilin 1 on chr 14, presenilin 2 on chr 1, and amyloid precursor protein on 21 associated with early onset AD
polygenic conditions
- androgenetic alopecia
- epilepsy
- schizophrenia
- glaucoma
- ischemic heart disease
- hypertension
- TIID
- malignancy
