Diseases Flashcards
Prader-Willi Syndrome
del 15q11-q13 of paternally derived chromosome or imprinting issues. SNORD116 a snoRNA genes which may be involved in mRNA modification. Hypotonic, trouble eating in infancy then excessive eating, short stature, sleep apnea from obesity, hypogonadism, opthalmic problems and intellectual disability. Growth hormone can improve stature and reduce apetite.
Angelman Syndrome
del 15q11-q13 of maternally derived chromosome or imprinting issues. Repressed gene UBE3A, a ubiquitin ligase. Short stature, severe intellectual disabilities,autism, seizures.
Acute Promyelocytic Leukemia
t(15;17)(q24;q21). PML/RARA fusion. High bone marrow blasts. Characterized by Auer rods. Treated with retinoic acid (vitamin a
Acute Myelogenous Leukemia
t(8;21)(q22;q22). ETO/AML fusion.
Chronic Myeloid Leukemia
t(9;22)(q34;q11.2). BCR/ABL1 fusion. Night sweats, fatigue, lobulated cells, splenomegaly. Treated with Gleevec.
IDIC 15
Supernumerary marker chromosome 47, i15q (inverted duplicted isodicentric) or a simple maternally inherited interstitial duplication of causes autism, hypotonia, seizures.
Early onset Alzheimer’s Disease
Locus heterogeneity related disease resulting in amyloid-B build up. Early onset the result of a mutation in PS-1, PS-2, or APP genes result in the same phenotype.
Androgen Insensitivity
Mutated X linked gene for androgen receptor. XY females that don’t develop uterus.
Adrenal Hyperplasia
46 XX female is exposed to testosterone and has abnormal cortisol production resulting in ambiguous genetalia
Smith-Lemli-Opitz syndrome
AR, Abnormal cholesterol synthesis (a precursor to testosterone) resulting in ambiguous male genitalia
Kallman syndrome
X linked AR, the hypothalamus doesn’t stimulate the pituitary to produce LH and FSH which normally stimulate testosterone production.
Hypospadias
Other than Smith-Lemli-Opitz and Kallman syndromes, a del 4p16.3 results in non funtional Steriod 5a-reductase, a necessary protein in testosterone metabolism
Duchanne Muscular Dystrophy
DMD Xp21.2 Large deletions, nonsense or frameshift mutations cause premature termination of protein. Abnormal gait, calf pseudohypertrophy, progressive deterioration of myocardium and respiratory muscles. Gower’s manuver.
Becker Muscular Dystrophy
Similar to but more mild than DMD and occurs at same locus, but the result of an inframe deletion which leaves protein semi funcitonal
Osteogenesis Imperfecta Type 1
AD. Premature termination of COL1A1 the gene for procollagen 1. Collagen composed of 2x procollagen 1 and 1x procollagen 2. Mutant gene results in slow collagen production thus reduced amount in tissue. Brittle bones, increased fractures, blue schlera.
Osteogenesis Imperfecta Type 2, 3, 4
Mutated COL1A2 (frameshift) resulting in abnormal procollagen 2 production. 1/2 of collagen made normal but 1/2 have the mut protein. More severe phenotype than the loss of function in OIT type 1. Often lethal.
Hemoglobin Kempsey
Asp99Asn missense mutation resulting in a higher oxygen binding affinity. At distal tissue sites, unable to unload much oxygen which causes body to up reg RBC production causing polycythemia
Fragile X
CGG repeats in 5’UTR of FMR1 cuase methylation and supression of transcription. Characteristic facies, hypotonia, cognitive deficits, and autism.
Huntington Disease
CAG repeats in the Huntington Disease gene (HD gene) results in a long chain of glutamine residues rendering the protein non functional. Norm 40. Severe neurodegenerative disorder with an onset correlated to # of repeats. Genetic anticipation; paternal expansion only.
Myotonic Dystrophy
CTG repeats in DMPK gene resulting in weakness, myotonia, cognitive defects. Less than 35 repeats is normal but repeats can get into the thousands with increasing phenotypic severity and earlier onset. Maternal expansion.
Phenylkentonuria
Defects in Phenylalanine hydroxylase (PAH) or cofactor BH4. Results in high phe level in blood and urine, epilepsy, cog defects and microcephaly. High alelic heterogeneity with varied phenotype severity. Treat with low phe diet W/ BH4 mut, patient also needs medicine for nuerotransmitter balance.
1a-antitrypsin deficiency
(ATD) Mutation in SERPINA1 a protease inhibitor that is suicide inhibitor of serine protease elastase. Elastin necessary for tissue but too much is bad. Increased risk of developing emphysema, liver cirrhosis, liver cancer. Symptoms more severe in smoker or high pollution. Z/Z is 15% act, improperfolding cuases accumulation and liver damage. S/S is 50% active, unstable protein but normal. S/Z mild.
Tay-Sach’s Disease
Lysosomal Storage Disorder where HexA is defective. HEXA (ch15) and HEXB (ch5) make HexA (a and b subs + activator) and HexB (2x b sub) enzymes that breakdown GM2 gangliosides. Also may be caused by GM2AP activator needed for GM2gang degredation.
Turner Syndrome
45, XO. Short stature, webbed neck, edema, shield chest, wide nipples, renal and cardiovascular anomalies (bicuspid aortic valve), failure in ovarian development. Sterile. Can be mosaic.