Named Disorders

Question 1

Friederich Ataxia

Answer 1

(AR) GAA repeats on Chr9 –> frataxin mutation; defective Fe binding protein in mitochondria. This damages dorsal columns (proprioception and vibration sense) as well as spinocerebellar tracts (ataxia, frequent falling). Also see kyphoscoliosis and pes cavus; risk of death from HCM; presents in adolescence (ages 5-15).

Question 2

Charcot-Marie-Tooth disease

Answer 2

(AD) Progressive hereditary neurodegenerative disorders due to defective production of the structure and function proteins of the peripheral nerves/myelin sheath. Presents as sensory and motor loss, as well as kyphoscoliosis and pes cavus, around age 30-40.

Question 3

Metachromatic Leukodystrophy

Answer 3

(AR) Lysosomal storage disorder due to arylsulfatase A deficiency and cerebroside sulfate accumulates, which impairs myelin sheath production (“leuko”- white dystrophy).
Get central and peripheral demyelination with ataxia around age 9-12mo, dementia, developmental delay, muscle weakness, atrophy, MRI showing demyelination.

Question 4

Isolated Atrial Amyloidosis (IAA)

Answer 4

form of senile amyloidosis (associated with aging) where ANP is misfolded and deposited in the cardiac atria; increases the risk of afib

Question 5

Actinic keratosis

Answer 5

Premalignant skin lesions that are rough with sandpaper like texture, “felt more than seen”, and start out as small/flat then become elevated and maybe even form horns (hyperkeratosis).
Caused by UV damage, therefore seen in people who worked outside a long time. Can progress to SCC (

Question 6

Acyl-CoA Dehydrogenase deficiency

Answer 6

The most common deficiency resulting in impaired FA oxidation; the missing enzyme is the one that starts FA oxidation (once the acyl-CoA has been transported into the mitochondrion by carnitine). Clinical = fasting child with vomiting and lethargy, maybe a seizure, and hypoglycemia and NO KETONES (no acetoacetate - hypoketotic hypoglycemia).
Differentiate from GSD because there will be no ketones here.
Differentiate from primary carnitine deficiency because that will also have muscle weakness, cardiomyopathy, and elevated TGs in addition to hypoketotic hypoglycemia.

Question 7

CGD

Answer 7

lack of NADPH oxidase means impaired NT respiratory burst and thus inc vulnerability to catalase positive bugs -
Especially Serratia, S. aureus, Burkholderia cepacia, Aspergillus, and Nocardia

Question 8

Homocystinuria

Answer 8

Methionine cycle = Met –> SAM –> SAH –> Homocysteine; Hom –> Met, OR Hom –> Cystathione –> Cysteine
If you can’t convert Homo–> cysteine (MC 2/2 deficiency of cystathione synthase) then homocysteine accum, which makes for a hypercoagulable state, can cause acute coronary syndrome (like 12yo with angina, or CVA), can also result in ectopia lentis, ID, and long slender fingers.
This would make cysteine an essential aa for these people because they can’t make it from homocysteine. Can also supplement B6 because even when the enzyme is deficient, 50% of patients respond to supplemental pyridoxine. Should also reduce dietary methionine.

Question 9

Hunter’s syndrome

Answer 9

deficiency of iduronate sulfatase; heparan sulfate and dermatan sulfate accumulate; similar to Hurler’s (gargolyism) except - no corneal clouding, and very aggressive

Question 10

Hurler’s syndrome

Answer 10

deficiency of alpha-L-iuduronidase; heparan sulfate and dermatan sulfate accumulate; developmental delay, loss of milestones (develop normally for a while, then they regress), gargoylism = dwarfism, distinct facial features (frontal bossing, hypertelorism, widened nasal bridge, gapped teeth, gingival hyperplasia, and thickened tongue), cloudy corneas, HSM, airway obstruction (from thickened tongue, leads to death)

Question 11

Hyperplastic arteriolosclerosis

Answer 11

when a patient has persistent diastolic HTN (>130), the arterioles get onion-like concentric thickening of the walls; this can lead to sustained HTN, kidney damage (oliguria), increased RAAS activity (vicious cycle), and potentially cranial sx like Has, papilledema, HTNive encephalopathy, and retinal hemorrhage/exudate

Question 12

Kallman syndrome

Answer 12

delayed puberty + anosmia

2/2 defective migration of GnRH cells into hypothalamus, so there’s no secretion of GnRH from hypothalamus

Question 13

Klinefelter syndrome

Answer 13

47,XXY male - primary hypogonadism, tall, gynecomastia, learning/social difficulties; dec. testosterone from damaged Leydig cells, inc. FSH/LH (no feedback; sclerosed seminiferous tubules), and inc. estradiol
Clinical hallmark is the hypogonadism - small firm testes; lack of 2ndary sex development - despite being tall

Question 14

Krabbe’s Disease

Answer 14

deficiency of galactocerebrosidase; galactocerebide accumulates; CNS symptoms like delayed development, optic atrophy (blindness), Globoid cells (multi-nuc MPs); “4mo old with seizures, irritability, vomiting, developmental delay, inability to track(blind)…”; differentiate from Fabry’s by optic atrophy

Question 15

Marfan vs. Ehlers-Danlos: mutation and clinical picture

Answer 15

Marfan = mutated fibrillin, all elastin all the time; person is really tall with long limbs, sunken chest; but doesn’t affect cartilage like joints

EDS = defective collagen synthesis (often lysyl hydroxylase or procollagen peptidase) to where the person has hypermobile joints, stretchy skin, and fragile tissue vulnerable to bruising

Question 16

MEN1, MEN2a, MEN2b

Answer 16

MEN 1: pituitary, parathyroid, pancreas
MEN 2A: parathyroid, pheo’s; medullary thyroid
MEN 2B: oral/GI neuroma, pheo’s; medullary thyroid

Question 17

Necrolytic migratory erythema

Answer 17

an elevated painful and pruritic rash affecting the face, groin, and extremities, the papules/plaques coalesce to form large lesions with bronze indurations; features in glucagonoma, which will also see high glucagon and which may present as new onset DM, +/- anemia of chronic disease

Question 18

Niemann-Pick Disease

Answer 18

deficiency of sphingomyelinase; sphingomyelin accumulates; tetrad of neuro probs/neurodegeneration, HSM, foam cells (fatty accumulation of sphingomyelin in MPs), cherry red macula

Question 19

Ornithine Transcarbamylase deficiency

Answer 19

Urea cycle: carbamoyl phosphate + ornithine –> citrulline

Deficiency = accum. carbamoyl phosphate, gets pushed into the pyrimidine synthesis pathway but then gets stuck at orotic acid
Findings: orotic acidemia/aciduria and hyperammonemia (a metabolic emergency - manifests as AMS/unresponsive and tachypnea); triggered by illness or excessive protein intake

*Differentiate from orotic aciduria alone: no megaloblastic anemia in OTC deficiency

Question 20

Primary carnitine deficiency

Answer 20

without sufficient carnitine (mitochondrial membrane transport protein for FAs), FA can’t be transported into the mitochondria; they won’t be oxidized and no acetyl-CoA will be produced for either TCA or ketone bodies

Question 21

Sarcoidosis

Answer 21

histo: non-caseating granulomas with epithelioid cells; CXR = bilateral hilar lymphadenopathy; typically a young black woman with non-specific sx like fever/malaise/wt loss; +/- skin involvement ranging from macules to painful shin nodules (erythema nodosum)

Question 22

Small Cell Lung Cancer

Answer 22

neoplasm of primitive cells from basal layer of bronchial epithelium; can have varying degrees of neuroendocrine differentiation, as such they may stain for chromogranin/synaptophysin/NCAM-1 (aka CD56)/neuron-specific enolase, and/or they may express neurofilaments and contain secretory granules; look like LCs but typically larger, arrange in sheets or clusters
This is the cancer associated with all the syndromes: Cushing’s, PTHrP, SIADH, Eaton-Lambert

Question 23

Tay-Sachs Disease

Answer 23

deficiency of hexosaminidase A (Tay-Six dz); GM2 ganglioside accumulates; neurological problems (CNS/peripheral), cherry red macula, NO HSM everrrrrr, onion skin lysosomes

Question 24

Lynch syndrome - associated cancers

Answer 24

colorectal; endometrial; ovarian

–> from MSH mutation

Question 25

CREST Syndrome

Answer 25

A type of limited scleroderma (limited meaning it doesn't include viscera) Anti-centromere antibodies are specific for limited scleroderma whereas anti-topo I are specific for diffuse scleroderma (aka systemic sclerosis) ``` C = calcinosis R = Raynaud's E = Esophageal dysmotility (like GERD or dysphagia) S = sclerodactyly (begins as non-pitting edema, then becomes thickened, ulcerated skin of hands/feet) T = telangiectasias ```

Question 26

Androgenetic alopecia

Answer 26

aka male-pattern baldness these people have higher levels of 5-alpha-reductase (turns testosterone into DHT) and a higher quantity of androgen receptors. Finasteride (a 5-a-reductase inhibitor) will reverse androgenetic alopecia.

Question 27

Turner syndrome

Answer 27

46,X Loss of paternal X chromosome Results in webbed neck/cystic hygromas, broad chest with wide nipples, streak/atrophic ovaries, short stature, horseshoe kidney, bicuspid aortic valve, coarctation of the aorta (diminished LE pulses), low set ears, low hairline, lymphedema (swelling of bilateral extremities), and overall short stature

Question 28

Congenital torticollis

Answer 28

A contracture of the SCM caused by fetal malpositioning in utero, or traumatic delivery (breech). This causes injury and fibrosis to the SCM, resulting in a fetal head position that is away from the side of injury. Typically presents clinically by 2-4wks of age.

Question 29

Triad of Wiskott Aldrich syndrome (and the rest of the disease)

Answer 29

Triad = thrombocytopenia, recurrent infections, eczema Disease is an X-linked deficiency of both B and T cells Tx is bone marrow transplant WASP = the defective protein, which results in T cells not being able to polarize and therefore can't make the immunologic synapse, can't activate B cells; also plays role in the small platelets (removed by the spleen hence thrombocytopenia)

Question 30

Alkaptonuria

Answer 30

AR deficiency of homogentisic acid dioxygenase; get accumulation of homogentisic acid (on its way to fumarate for TCA cycle). Relatively benign in childhood, then severe arthritis in adult life with pigment deposition in cartilage (blue-back spots in sclera and ear); the deposits are also in joints which causes ankylosis, restricted movement, and pain +pee that turns black overnight

Question 31

Hirschsprung's disease

Answer 31

Failure of neural crest cells to migrate down to form the submucosal (Meissner's) and myenteric (Auerbach) plexus; always involves the rectum because that would be the farthest sites to migrate to. Dx with submucosal biopsy of the narrowed portion of the bowel (because the dilated part proximal to that is where everything is getting stuck, that's why it's big).

Question 32

Lead poisoning

Answer 32

Child or someone who works in industry - abdominal pain, weakness, constipation, and in severe cases neuro sx (causing HA, cognitive sx, peripheral neuropathy) Blood smear: basophilic stippling on background of hypochromic, microcytic anemia vs. Acute porphyria - episodes of abdominal pain without tenderness, and no anemia

Question 33

Arginase deficiency

Answer 33

In urea cycle* Normally: converts Arginine + H2O --> Ornithine + Urea Without it: build up of Arginine in blood, spastic diplegia, and growth delay ("3yo boy with progressive bilateral leg stiffness and abnormal involuntary movements with delayed cognitive development") Differentiator is nearly no hyperammonemia at all *The only urea cycle enzyme deficiency that is XLR

Question 34

Fanconi anemia

Answer 34

Inherited disorder of bone marrow causing aplastic anemia. The patient will also be short and thumbs are absent. Increased risk of malignancy like MDS and AML.

Question 35

Polyarteritis nodosa

Answer 35

medium-vessel vasculitis - usually idiopathic; associated with HbsAg - renal, skeletal, neuro, and visceral (GI) vessels (NOT lung); episodes of system symptoms due to ischemia - string of pearls on imaging from: transmural inflammation of vessel wall with fibrinoid/eosinophilic necrosis - immune complex mediated, especially when associated with HepBsAg (30% of cases)

Question 36

Leser-Trelat

Answer 36

the acute eruption of multiple seborrheic keratoses that are associated with underlying internal malignancy

Question 37

Myotonic muscular dystrophy

Answer 37

- 2nd MC inherited muscle disorder (AD), behind DMD - caused by CTG repeats - will always see myotonia (slow relaxation) and cataracts; frontal balding and gonadal atrophy are also common

Question 38

Essential Fructosuria vs. Aldolase B deficiency

Answer 38

Essential Fructosuria is benign (AR) and fructose will simply be excreted in the urine. Aldolase B deficiency is bad and presents as soon as fruit juice is introduced into the diet; infants will get jaundice, hepatomegaly, and failure to thrive.

Question 39

Rett Syndrome

Answer 39

- hypotonia and hand ringing - loss of developmental milestones around age 5-18mo as well as deceleration of head growth (early sign) - normally in girls - most cases are due to de novo mutation in X linked gene

Question 40

Wilson Disease

Answer 40

mutation in ATP-B7 Cu transport protein in the Golgi - will see Cu overflowing from HCs because it can't be excreted; will instead be deposited in tissues like the brain, cornea - therefore hepatic, neuro/psych, and Kayser-Fleischer rings are clinical findings - lab findings include increased Cu in liver biopsy and in urine, as well as decreased Ceruloplasmin (serum Cu transport) - treat with D-Penicillamine

Question 41

Minimal change disease

Answer 41

- a protein loss in the kidneys defined by loss of negative charge selectivity in the GBM; will see Albumin (and potentially other proteins like IgG or B2-microglobulin) in the urine - this type of nephropathy is a selective nephropathy

Question 42

Guillan-Barre

Answer 42

- antibodies against myelin; so you get segmental demyelination and endoneural inflammatory infiltrate (on LM will see LC/MPs) - most often following URI, esp. Campylobacter jejuni

Question 43

Tuberous sclerosis

Answer 43

brain tubers, subependymal hamartomas, ash-leaf skin patches, renal angiomyolipoma, cardiac rhabdomyoma, facial angiofibroma

Question 44

Multiple sclerosis

Answer 44

- neuro issues separated by time and space, due to demyelination with relative sparing of the axons by autoantibodies - IgG oligoclonal bands in CSF, sclerotic plaques (astrocytosis/glial scarring/inflammation) on MRI, as well as lipid-laden MPs from myelin clean-up - Intranucleuar opthalmoplegia (INO) is a sx caused by demyelination of the MLF

Question 45

Familial Hypocalciuric Hypercalcemia

Answer 45

- mutated CaSR (a GPCR) that can't tell if you have enough Ca; so PTH is high, Ca in blood is high, and Ca in urine is low - benign, AD disorder - mutated CaSR found in kidneys and parathyroid gland

Question 46

Major Depressive Disorder

Answer 46

A major depression (all day consecutively) lasting longer than 2 weeks Without mania or hypomania because then that would be bipolar; must rule out bipolar and substance issues.

Question 47

Hashimoto thyroiditis

Answer 47

The MCC of hypothyroidism in the US - first inflammatory infiltrate and destruction of the thyroid - then high TSH because it's trying to get it produced - thyroid doesn't work so T4 is low - T3 is normal though, until late-stage

Question 48

Achalasia

Answer 48

an esophageal dysmotility disorder in which there's a loss of ganglion cells in the lower esophagus; carries inc. risk of SCC

Question 49

Three important inherited mitochondrial disorders

Answer 49

1. Leber hereditary optic neuropathy --> bilateral vision loss 2. Myoclonic epilepsy with ragged red fibers --> seizures and myopathy associated with exercise 3. Mitochondrial encephalomyopathy with lactic acidosis and stroke-like symptoms (MELAS) --> kid has prior seizures, now with stroke like symptoms as well as myopathy (sister might not be as bad due to heteroplasmy)

Question 50

Transference vs. Counter-transference | and Displacement

Answer 50

Transference is when a patient puts expectations/has feelings toward a physician that are not so much about the physician themself but rather about whoever in their past that the physician reminds them of; like a patient with daddy issues is upset when the physician cancels because he thinks he's being abandoned again. Counter-transference is when the physician does it to the patient; puts expectations on this based on people from the doc's past. Displacement = the chain of yelling

Question 51

Opsoclonus-Myoclonus syndrome

Answer 51

- a syndrome of myoclonus, associated with rhythmic conjugate eye movements - most often associated with neuroblastoma, which happens to be the most common extracranial childhood cancer in kids and peaks at 2yo

Question 52

Paget Disease of Bone

Answer 52

Overactive Osteoclasts *even though it's diagnosed by inc. alk-phos (OBs) and really hard but lamellar bone; it originates because there's overactive OCs for some reason, eating the bone, and the OBs have to react quickly and don't make their best bone

Question 53

Congenital CMV

Answer 53

seizures, ventriculomegaly, periventricular calcifications, sensorineural hearing loss, chorioretinitis *TORCHeS infection

Question 54

Post-Strep Glomerulonephritis

Answer 54

- hematuria + proteinuria + RBC casts in urine + hypercellular glomeruli on LM (from LC infiltration and endothe/mesangial proliferation) * *Especially in a kid, after URI. - Additional findings will include ASO Abs, anti-DNAse B, anti-cationic proteinase, and dec. C3 in serum - On IF: coarse, granular deposits of IgG and C3

Question 55

Jervell | Lange-Nielsen syndromes

Answer 55

These are congenital long QT syndromes that are associated with torsades and sensorineural deafness. Other variants include Romano-Ward and Burgada.

Question 56

Ortner syndrome

Answer 56

the impingement of the left recurrent laryngeal nerve that is caused by enlargement of the left atrium from say mitral stenosis

Question 57

Henoch-Schönlein pupura

Answer 57

- small vessel vasculitis typically occurring in boys age 2-10; follows viral or strep URI - thought to be IgA deposition mediated - effects most prominently seen in GI (bleeding, edema, intussusception); kidney (crescent formation, mesangial proliferation); palpable purpura on buttocks and legs; and joints (self-limited arthralgias and arthritis in large joints)

Question 58

Sequence of Hyperaldosteronism

Answer 58

- too much ALD produced, get Na retention, water follows, loss of K+/H+ - kidneys get high pressure inflow and secrete natriuretic peptide to compensate which dumps Na and H20 - leads to a limit to net sodium retention, avoidance of overt volume overload (so no edema, etc.) - results in electrolyte imbalance enough to create paresthesias/muscle weakness, but on labs will see normal Na, low K, and low H/high bicarb (alkalosis)

Question 59

Complications of OSA

Answer 59

- systemic HTN and pulmonary HTN - from chronic NE/SNS activity - R heart failure (2/2 Pulm HTN) - a-fib, arrhythmias, and coronary disease - increased risk of stroke, SCD

Question 60

Acute Intermittent Porphyria

Answer 60

deficiency of Porphobilinogen deaminase (converts Porphobilinogen to Urobilinogen) 5 P's: 1. painful abdomen 2. port-wine colored urine 3. polyneuropathy 4. psychological disturbances 5. precipitated by drugs (barbiturates)

Question 61

Porphyria cutanea tarda

Answer 61

deficiency of Uroporphyrinogen decarboxylase (converts Uroporphyrinogen to Coproporphyrinogen) - most common porphyria - tea colored urine, blistering cutaneous photosensitivity

Question 62

Ammonioagenesis

Answer 62

Glutamine is made in the liver and transported to the kidney (carries amino groups to get rid of) Metabolized by ?????? into 2 bicarbs (reabsorbed to blood) and 1 NH4+ which is excreted (into lumen/urine)

Question 63

Dysostosis Multiplex

Answer 63

mucopolysaccharide disorder: deficiency of beta-galactosidase, build-up of keratan sulfate/GM1; causes neurodegeneration, seizures, HSM, gait problems, joint problems, muscle weakness, skeletal irregularities *think about Tay-Sachs, this can also get cherry-red macula (50%)

Question 64

I cell disease

Answer 64

an LSD - defective addition of mannose-6-phosphate, so lysosomal enzymes aren't targeted to the lysosome - they are secreted instead and end up doing their activity outside the cell - coarse facial features, clouded corneas, restricted joint movement, and high plasma levels of lysosomal enzymes

Question 65

Caplan syndrome

Answer 65

Coal workers pneumoconiosis plus RA

Question 66

Anthracosis

Answer 66

Carbon-laden MPs in the lungs (or lymph nodes) from urban exposure, benign

Question 67

Myoedema

Answer 67

A localized swelling of the muscle that is secondary to slow reabsorption of Ca into the SR Can be elicited by tapping the muscle with a reflex hammer. If occurs in the setting of elevated CK, it's highly suggestive of hypothyroidism; check TSH.

Question 68

PKU

Answer 68

MCC is deficiency of phenylalanine hydroxylase, resulting in hyperphenylalanemia, hypopigmentation (no melanin for skin, eyes, hair, and catecholaminergic brain cells), intellectual disability, seizures, and musty body odor. Could also be affected by BH4/dihydropteridine deficiency. *In US it's a newborn screen, so it won't usually progress that bad, but an immigrant kid will probably present at 2-3yo

Question 69

Congenital hypothyroidism

Answer 69

Either due to iodine deficiency or thyroid agenesis; baby will show signs of hypothyroidism around 2mo, since mom's thyroxine from transplancetal transfer is there at first. Thyroid hormone is needed for metabolism and brain development, hence intellectual disability; also see bulging anterior fontanel, bulging/protruding tongue, and bulging umbilical hernia. May also have swollen face from subcutaneous myxedema.

Question 70

Partial vs. Complete mole

Answer 70

Partial = normal egg gets fertilized by 2 sperm; 69,XXY or 69,XXX; the extra set of chromosomes is always paternal in origin Fetal tissue present with focally enlarged villi; focally hyperplastic trophoblasts Complete = empty egg, usually gets fertilized by 1 sperm that duplicates, rarely fertilized by 2 sperm so more likely to see 46,XX No fetal tissue present, diffusely enlarged villi, diffusely hyperplastic trophoblasts

Question 71

Inguinal Hernia

Answer 71

Direct = through the peritoneum/abdominal wall weakness; medial to the epigastric vessels Indirect = through the tunnel (deep inguinal ring); lateral to the epigastric vessels --> Tunnel: FTFTA IOEO-AIL Superficial inguinal ring is the opening in the external oblique aponeurosis

Question 72

Rapidly Progressive Glomerulonephritis (RPGN)

Answer 72

3 causes: 1. Anti-GBM/Goodpasture: will see IgG and C3 deposits on BM; may also have pulmonary hemorrhage/sx and will see decreased serum IgG/C3 2. Immune Complex deposition: on IF there's a lumpy-bumpy pattern of deposition of IgG and IgA; can be sequence of SLE, post-strep, Henoch-Schonlein, or IgA Nephropathy 3. Pauci-Immune: no IF staining for antibodies, associated with Wegener's and micropscopic polyangiitsi, so should look for ANCA; may also have URI involvement

Question 73

Caudal regression syndrome

Answer 73

Congenital failure of lumbar spine/sacrum to develop -- most commonly sacral agenesis but could be anal agenesis up to way more severe regression. Highly associated with poorly controlled maternal DM.

Question 74

Vitamin A overdose - congenital effects

Answer 74

- craniofacial and posterior fossa deformities - auditory defects - great vessel defects, similar to those in DiGeorge

Question 75

Hepatitis E

Answer 75

- A/E are AcutE hepatitis, and fEcAl-oral route - Hep E is unenveloped - high mortality in pregnant women but NOT transmitted parenterally (see fecal-oral above)

Question 76

Carcinoid syndrome vs. VIPoma

Answer 76

- Carcinoid syndrome = wheezing, diarrhea, facial flushing; from carcinoid tumor that has spread to liver (and has direct arterial access) - VIPoma = WHDA * *Symptoms of both can be treated with Octreotide which is a longer-lasting somatostatin analog; somatostatin controls not only GI substance release but also hormone release in general.

Question 77

Treatment-Resistant Schizophrenia

Answer 77

- means they had poor response to at least 2 antipsychotics and continues to be symptomatic - time for clozapine -- but beware of neutropenia and agranulocytosis (also seizures and metabolic problems)

Question 78

Dopamine hydroxylase deficiency

Answer 78

Deficiency of Da hydroxylase which normally makes Ne from DA; without it the pt will have dysautonomic characterized by ptosis, orthostatic HOTN, hypoglycemia, and hypothermia

Question 79

Mixed Acid-Base disturbances

Answer 79

- The pt starts out with one type of acidosis/alkalosis; then the compensatory reaction decreases/fails - In lactic acidosis/DKA will have to look for bicarb compensation; normal is a 1pt inc/2pt dec in bicarb for every 10pt change in CO2 (be that down or up, resp.); this can tell you if there's a failure of respiratory compensation - Will also have to look at kidney function to see if there's a failure of metabolic compensation * DKA can be precipitated by viral infection

Question 80

Familial Dysbetalipoproteinemia vs. Familial Hyperlipidemia

Answer 80

Dysbeta = defective ApoE, can't reuptake chylomicron/VLDL remnants; get eruptive xanthomas (palms/soles) and premature athero HLD = defective ApoB100 and LDL-R, can't reuptake LDL; get xanthelasma, tendon xanthomas, and premature athero

Question 81

Familial Chylomicronemia vs. Familial Hypertriglyceridemia

Answer 81

Chylomicronemia = defective LPL and ApoC2; can't reuptake chylomicrons Hypertriglyceridemia = many proteins defective, can't reuptake VLDL

Question 82

Hemochromatosis

Answer 82

mutation in HFE gene/protein which is supposed to bring in the transferrin-Fe complex to add to the stores; if mutated it makes it look like you're iron-deficient so 2 things happen: 1. enterocytes express more DMT1 on their apical surface to absorb Fe from the lumen 2. HCs decrease hepcidin expression, which normally would decrease ferroportin (on EC basolateral membrane) and stop the transport of Fe into blood from EC

Question 83

In infant: Result of no Sertoli cells Result of no Leydig cells

Answer 83

Sertoli cells produce MIF for inhibiting female internal genitalia (paramesonephric ducts); without it you get female internal genitalia. Leydig cells produce Testosterone for promotion of Wolffian ducts and conversion into DHT for external male genital differentiation; without it there's no internal or external male genitalia.

Question 84

Hepatocellular carcinoma and Hepatitis B

Answer 84

MOA is unclear but it has to do with HepB having integrated into the DNA

Question 85

Menier's disease

Answer 85

accumulation of endolymph that causes excessive motion of the tectorial membrane and vertigo with hearing loss/tinnitus; causes recurrent episodes (as opposed to vestibular neuritis which is one viral/post-viral episode of vertigo only, no hearing loss)

Question 86

Primary myelofibrosis

Answer 86

Atypical MKC hyperplasia which stimulates fibroblasts and replaces the bone marrow with fibrosis. Sx include severe fatigue, HSM (which can cause abdominal discomfort/early satiety), anemia. Caused by a JAK mutation.

Question 87

Fragile X Syndrome

Answer 87

Prominent forehead and chin, long narrow jaw, large testes, speech/motor delay in infancy and/or neuropsychiatric issues in adolescence (ADHD, ASD, anxiety), and hyperlaxity of joints in the hands Caused by small deletion/LOF mutation in the FMR1 gene on the long arm of the X chromosome *females will have a milder presentation if heterozygous

Question 88

Patau syndrome - clinical appearance

Answer 88

Trisomy 13: rocker bottom feet, umbilical hernia/omphalocele, renal/cardiac defects, multiple fingers, cleft lip/palate, microphthalmia, microcephaly, and cutis aplasia (membrane-covered opening in scalp)