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Diseases Flashcards

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1
Q

Sickle Cell Anemia

A

Missense SNS in HBB gene (Glu to Val)

Tx: hydroxyurea to derepress HbF so HbF will be expressed

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2
Q

Leber’s Hereditary Optic Neuropath (LHON)

A

Mitochondrial inheritance

ROS: blindness at 20-30 years old

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3
Q

Friedreich Ataxia

A

AR
Cause: triplet (GAA) in intron 1 of frataxin gene
Mechanism: methylation and silencing of the gene, mitochondria unable to assemble ETC
ROS: ataxia and muscle weakness, neuro-degenerative, heart dz

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4
Q

Homocysteinuria

A

AR - variable expression (more severe in males)

*allelic heterogeneity, delayed onset

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5
Q

Holoprosencephaly (HEP)

A

Cause: SHH mutation
ROS: head/face deformities (cleft palate to cyclopia)

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6
Q

PKU

A

Newborn screening by mass spectroscopy

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7
Q

Becker’s Muscular Dystrophy (BMD)

A

X-linked, in-frame mutation of dystrophin gene

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8
Q

Beckwith-Weidmann Syndrome

A

Abnml methylation and imprinting of 11p15, parental uniparental disomy (IGF2
ROS: macroglossia, high birth weight
*child born of IVF has 4-9 fold higher chance of BWS

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9
Q

Angelman Syndrome

A

*UBE3A is paternally imprinted
Cause: chromosome 15q11 deletion, missing/mutated maternal UBE3A (since paternal gene is silenced the pt will have the dz phenotype)
ROS: “happy puppet”, MR, sz, wide mouth

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10
Q

Butyrlcholinesterase Polymorphism

A 
AR
Cause: BCHE gene def
Mechanism: decreased rate of metabolism of succinylcholine
ROS: prolonged paralysis
Tx: continued ventilation
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11
Q

UV Light

A

Causes pyrimiding dimers or thymine dimers

Repair: by nucleotide excision repair

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12
Q

Pleiotropy

A

mutation affecting multiple organ systems

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13
Q

Fragile X Syndrome

A

X-linked - *maternal anticipation
Cause: triplet (CGG repeat) in 5’UTR promoter before FMR1 gene, causes methylation and silencing of FMR1
ROS: MR, prominent ears, elongated face and macroorchidism (enlarged testes)
*CGG will recruit deacetylase and shut off the FMR1 gene

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14
Q

Klinefelter Syndrome

A

47, XXY due to nondisjunction in meiosis I in males
ROS: testicular atrophy, gynecomastia (male breasts), female distribution of hair, infertility
*have extra Barr body

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15
Q

Chronic Myeloid Leukemia (CML)

A

Cause: hybrid BRC-ABL fusion protein/oncogene (philadelphia chromosome)
ROS: unregulated/constitutive tyrosine kinase activity, Abl is stuck in its active form
Tx: imatinib
*t(9;22) - reciprocal translocation

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16
Q

Huntington’s Syndrome

A

Cause: triplet repeat of CAG (glutamine coding) that is
*gain of function in Huntington gene, polyglutamate disorder, delayed onset
Dx: PCR w/ electrophoresis

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17
Q

CYP2D6 Polymorphism

A

AR
Cause: CYP2D6 gene def
ROS: adverse side effects to Metoprolol, Codeine will be ineffective

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18
Q

A1AT (alpha-1 antitrypsin def)

A

Cause: mutationof SERPINA1
ROS: PMzz = emphysema, (Z allele - causes idiopathic polymerization of the protein in the liver leading to liver damage) PIzz = liver cirrhosis

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19
Q

Charcot-Marie Tooth Dz

A

AD, AR or X-linked shows locus heterogeneity

ROS: peripheral neuropathy

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20
Q

G6PD Deficiency

A

Hemolytic anemia caused by drugs inducing oxidative stress (sulfonamides, antimalarials, chloramphenicol)
*also caused by fava beans

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21
Q

Bloom Syndrome

A

Def: BLM gene, DNA helicase
ROS: small stature, narrow chin, prominent nose/ears, facial rash upon sun exposure, often DM and neuro/lung/immune syst def

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22
Q

Penetrance

A

all or nothing, whereas variable expression isn’t

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23
Q

X-Linked

A

Hemophilia A and B, G6PD deficiency, DMD and BMD, red/green color blindness, Lesch-Nyhan, X-SCID

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24
Q

Spinocerebellar Ataxia

A

Cause: CAG triplet repeat
ROS: limb ataxia, lack of muscle coordination, generally nml mental capacity
*variable age of onset, locus heterogeneity

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25
Achondroplasia
AD - full penetrance Cause: missense SNS in FGFR3 gene (codes for receptor involved in differentiation of cartilage/bone) *gain of function mutation *80% by mutation during spermatogenesis in older fathers
26
ICF (Immunodeficiency-centromeric instability-facial anomalies) Syndrome
Mutation in Dnmt3b gene | ROS: facial dysmorphism, MR, recurrent infections
27
Duchenne's Muscular Dystrophy (DMD)
X-linked recessive; frameshift mutation in dystrophin gene | *33% of pt's have new mutation due to "hot spots" on the gene
28
X-linked SCIDS
*Locus heterogeneity Defect in SCIDX1 gene, encodes for gamma-chain receptor in ILs (IL2RG), without this receptor T-cells and B-cells cannot mature
29
Allelic heterogeneity
Different mutations on same gene causing the disease
30
Steroid Sulfatase Def
.
31
Alkaptonuria
Def: homogentisic acid oxidase ROS: discoloration of cartilage and CT
32
Lynch Syndrome (HNPCC)
Cause: MSH2 or MLH1 mutation, results in microsatellite instability ROS: single polyps, accelerated
33
Marfan Syndrome
Dominant-negative AD disorder, shows pleiotropy
34
Pallister-Hall Syndrome
Cause: Gil gene mutation ROS: brain tumors, polydactyly
35
Myotonic Dystrophy
AD - maternal anticipation Cause: triplet (CTG repeat) mutation in the 3'UTR of DMPK gene Mechanism: sequesters RNA binding proteins to alternate splicing of many RNAs leading to altered cell function ROS: muscle wasting, cataracts, endocrine changes, mytonic and heart defects Dx: RFLP w/ Southern Blot
36
Wolf-Hirschhorn Syndrome
Def: deletion of chromosome 4p ROS: widely spaced eyes, prominent nose, abnml iris, cardiac anomalies, dev delay
37
Rubinstein-Taybi Syndrome
Cause: CREBBP gene mutation ROS: broad thumbs/toes, mental disability, short stature, small head, facial abnormalities
38
Ataxia telangiectasia
AR Defect in ATM (normally senses DNA damage and fixes DOUBLE STRANDED BREAKS) ROS: ataxia, inc risk of ca, subconj bv
39
Familial Adenomatous Polyposis
Mutation: APC gene (chromosome 5) ROS: multiple polyps in colon
40
Autosomal Dominant Dz (AD)
Vertical inheritance, male-to-male transmission, 50% risk of transmission E.g. - Huntington, myotonic dystrophy, familial hypercholesterolemia, osteogenesis imperfecta, Marfan, Achondroplasia, NF, acute intermittent porphyria
41
Intrinsic apoptosis pathway
Cytochrome c | - released by mitochondria
42
Burkitt Lymphoma
Cause: Myc oncogene (fused to IgH promoter @ t(8;14) --> ROS: increases production of Myc, lymphocytes fail to differentiate (undergo rapid cell divisions), commonly presents in children
43
Inherited Retinoblastoma (RB)
Cause: Rb gene mutation on chromosome 13 Mechanism: inherited/germline mutation and then second hit of somatic/sporadic mutation would cause manifestation of Ca (usually at young age) b/c the G1/S checkpoint is destroyed
44
Cytotoxic T cells
Granzyme/perforin killing, CD8+, Type IV HS
45
Li-Fraumeni Syndrome
Cause: TP53 mutation ROS: SBLA (sarcoma, breast, leukemia, adrenal gland tumors)
46
Thiopurine S-Methyltransferase Polymorphism (TPMT)
TMPT catalyzes S-methylation of thiopurine drugs, which inactivates them ROS: myelosuppression if lower does of thiopurine not given bc the pt is unable to
47
Smith-Lemli-Opitz Syndrome (SLOS)
Cause: 7-dehydrocholesterol reductase mutation (last step in cholesterol synthesis) ROS: microcephaly, MR, syndactly and polydactyly
48
Cystic Fibrosis (CF)
Defect: CFTR gene on chromosome 7 (ΔF508 most common) Mechanism: defective Cl- secretion in GI and respiratory epithelium, and defective Cl- reabsorption in sweat glands ROS: steatorrhea, pulmonary infections, fat soluble vitamin deficiency, pancreatitis, infertility in men, nasal polyps, finger clubbing Dx: ASO Dot Blot, Cl- sweat test
49
Rett Syndrome
X-linked Dominant *germline mosaicism Cause: MeCP2 mutation *affects females more than males bc males die in utero ROS: lose speech, lose acquired hand skills, sz, irregular breathing/motor control problems
50
Down Syndrome
Trisomy 21 via nondisjunction during oogenesis (meiosis I nondisjunction most common) ROS: ASD, Alzheimer’s, ALL, AML Dx: Karyotype, increased inhibin when in utero
51
Patau Syndrome
Trisomy 13 via nondisjunction during oogenesis ROS: polydactyly, cleft lip/palate, microcephalic, cardiac abnormalities, microphthalmia Dx: Karyotype
52
T-tract allele
Aka bad intron, relating to poor splicing efficiency so little mRNA is being produced and less of the protein is produced
53
Compound heterozygone
Different versions of a mutation of the same gene but still phenotypically affected with dz
54
de la Chapelle Syndrome
Cause: translocation of SRY gene on Y chromosome bc of unequal crossing over during meiosis ROS: nml male genitalia, 10% have hypospadias, infertility *46, XX
55
Herceptin
Ab against HER2 oncogene in HER2+ breast ca tumors | *blocks Tyrosine Kinase
56
Gain-of-function
Increased levels of gene expression or development of a new function of the gene product E.g. - Huntington's Dz, achondroplasia
57
Osteogenesis Imperfecta (OI)
AD, shows pleiotropy and locus heterogeneity Defect: COL1A1 or COL1A2 Mechanism: decreased production of otherwise normal type I collagen Type 1 - haploinsufficiency AD Type 2, 3, 4 - dominant negative AD ROS: blue sclera, abnormal ossicles, fractures *
58
DiGeorge Syndrome
Cause: microdeletion of 22q11 ROS: cardiac abnormalities, abnml facies, thymine aplasia, cleft palate, hypocalcemia/hypoparathyroidism Dx: FISH *aka VCFS
59
Locus heterogeneity
Mutations at different loci that cause the same dz phenotype
60
Wilms Tumor (Nephroblastoma)
Cause: loss-of-function of WT1 gene on chromosome 11 (WT1 encodes for TF important in control of cell growth and differentiation) Biopsy: glomerular structures *assoc w/ WAGR complex, Denys-Drash, and Beckwith-Weidemann
61
Sporadic Retinoblastoma (RB)
Mechanism: new mutation of Rb gene on chromosome 13 ("second hit" bc pt has already inherited a germline mutation and the second somatic mutation causes the dz phenotype)
62
Cri-du-chat Syndrome
Cause: deletion of chromosome 5p ROS: cat-like cry, severe intellectual disability, speech problems, microcephaly Dx: FISH
63
Prader Willi Syndrome
*SNRPN is maternally imprinted Cause: chromosome 15p11 deletion, missing/mutated paternal Snrpn (since maternal gene is silenced the pt will have the dz phenotype) ROS: obesity, hyperplasia
64
Hypochondroplasia (HYP)
Cause: mutation in proximal and distal tyrosine kinase ROS: mild severity, limps disproportionate
65
N-acetyltransferase 2 Polymorphism
Homozygous AR Mechanism: decreased catalyzation of isoniazid/hydralazine/sulfonamides ROS: neuropathy and hepatotoxicity (isoniazid administration), drug induced SLE (hydralazine/procanimide administered), hypersensitifity rxn's (Sulfonamides administered)
66
Swyer Syndrome (Pure Gonadal Dysgenesis)
Cause: loss of function mutation of SRY ROS: nml female genitalia, delayed puberty, 👆🏽LH causing clitoromegaly *46, XY
67
Familial Hypercholesterolemia
AD - haploinsufficiency, delayed age of onset Deficiency: LDL receptor ROS: elevated LDL (isolated)
68
Acute Intermittent Porphyria (AIP)
AD - haploinsufficiency Deficiency: porphobilinogen delaminates Accumulation: porphobilinogen, δ-ALA ROS: urine darkens on standing, polyneuropathy, psych disturbances, precipitated by drugs (CYP inducers +) EtOH and starvation
69
Lesch-Nyhan Syndrome
X-linked Defect: HGPRT (purine salvage) Accumulation: uric acid ROS: self mutilation
70
Gorlin Syndrome
Cause: patched (Ptc) mutation ROS: early age basal cell carcinoma, rib defects
71
Myoclonic Epilepsy (MERRF)
Mitochondrial inheritance ROS: progressive epilepsy, ragged red muscle fibers *heteroplasmy
72
Malignant Hyperthermia
AD Cause: ryanodine receptor def (RYR1 gene) ROS: tachycardia, HTN, muscle rigidity, hyperthermia, hyperkalemia, acidosis
73
Turner Syndrome
Defect: 45X_ Mechanism: paternal nondisjunction in meiosis I ROS: short stature, webbed neck, gonadal dysgenesis, primary amenorrhea *germline mosaicism
74
Thanatrophoric Dysplasia (TD)
Cause: mutation in distal tyrosine kinase ROS: severe (often lethal), usually still born or die shortly after birth
75
Dominant-negative
Mutant gene product interferes with the function of the normal gene product E.g. - OI Type 2, 3, 4; Marfan
76
MELAS
Mitochondrial inheritance ROS: encephalomyopathy, lactic acidosis, stroke-like episodes *heteroplasmy
77
Xeroderma Pigmentosum
AR - locus heterogeneity (mutation in 9 diff NER genes) Defect: can’t repair thymidine dimers caused by UV light ROS: extreme sun sensitivity, sunburn, blistering, freckled skin lesions Complication: skin malignancies (all 3 types)
78
Incontinentia Pigmenti
X-linked dominant Def: IKBKG (inhibitor of kappa light polypeptide gene) Effects primarily females bc males die in utero ROS: rashes/blisters, MR, retinal detachment, "marble cake appearance" of skin *variable expressivity due to X-inactivation
79
Haploinsufficiency
Loss-of-function mutations in which 1/2 nml levels of the gene product result in phenotypic effects E.g. - Familial Hypercholesterolemia, AIP, OI Type I
80
Hemochromatosis
``` AR with allelic heterogeneity Cause: mutation in the HFE gene ROS: delayed age of onset Dx: ASO Dot Blot *variable expressivity ```
81
Hemophilia A
X-linked - allelic heterogeneity Deficiency: Factor VIII ROS: increased tendency to bleed Labs: increased PTT, normal BT
82
Tay-Sachs
AR - frameshift mutation Deficiency: Hexosaminidase A Accumulation: ganglioside ROS: cherry-red spot on macula, onion skin lysosomes
83
Autosomal Recessive Dz (AR)
Horizontal inheritance, parents are carriers and siblings more commonly effected (2 carrier parents = 25% chance of affected child) E.g. - CF, PKU, Tay Sachs, Sickle cell, thalassemia, hemochromatosis, homocystineuria, SCID due to ADA deficiency, alkaptonuria
84
Edward Syndrome
Defect: trisomy 18 via nondisjunction during oogenesis ROS: clenched fists/overlapping fingers, rocker bottom feet, congenital ❤️ defects, low-set ears, microcephalic, intellectual disability Dx: karyotype
85
Anticipation
A phenotype can become more severe in successive generations, due to expansion of repeat sequences e.g. -triplet repeats get larger from one generation to the next so expressivity of the phenotype gets worse
86
Neurofibromatosis (NF-1)
AD - *allelic heterogeneity ("hot spot") Cause: NF1 mutation (can't shut off RAS) ROS: cafe-au-lait spots, neurofibromas, Lisch nodules in iris *variable expressivity

Genetics (3 decks)

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