Inborn error of Metabolism

Question 1

Cutaneous and subcutaneous neurofibromas

Cafe au lait spots

Lisch nodules (pigmented nodules of the iris)

Freckles in groin or axilla

Gliomas of optic nerve

Skeletal lesions: thinning of the cortices of long bones

Loss of GAP (GTPase activating proteins) activity permits uncontrolled activation

Autosomal dominant, mutation of what gene/chromosome??

Answer 1

Neurofibromatosis Type I (gene is NF1 on 17)

Question 2

Bilateral tumors of CN VIII (acoustic neuromas)

Juvenile cataracts

Meningiomas

Gliomas

Ependymomas

LOH of gene coding tumor suppressor merlin/schwannomin

Mutation of what gene/chromosome #?

Answer 2

Neurofibromatosis Type 2

Gene NF2 on Chrom 22 (Think Type 2 = 22)

Question 3

Deficient Homogentisate oxidase (pathway of tyrosine to fumarate)

Homogentisate substrate accumulates (toxic to cartilage)

BLACK URINE and cartilage when exposed to air/light (check First Aid/goljian)

Degenerative arthritis

Autosomal recessive, benign disease

Inborn error of metabolism?

Answer 3

Alkaptonuria

Question 4

Deficient GALT (galactose-1-P uridyltransferase)

Galactose-1-P accumulates (toxic to liver, CNS)

Galactose (in urine), Galactitol (alcohol sugar causes osmotic damage)

Mental retardation, cirrhosis, hypoglycemia, cataracts, AVOID DAIRY PRODUCTS I

nborn error of metabolism?

Answer 4

Galactosemia

Question 5

Deficient Aldolase B

Fructose 1-P accumulates (toxic) accumulates

Cirrhosis, hypoglycemia, hypophosphatemia, AVOID FRUCTOSE/SUCROSE

Inborn error of metabolism?

Answer 5

Hereditary fructose intolerance

Question 6

Deficient cystathionine synthase

Homocysteine and methionine accumulates

Mental retardation, vessel thrombosis, lens dislocation, arachnodactyly, tall stature, kyphosis, atherosclerosis (stroke and MI)

Decrease methionine, increase cysteine, increase B12 and folate in diet.

Inborn error of metabolism?

Answer 6

Homocystinuria

Also 2 other types

1) Cystationine synthase deficiency
2) Decrease affinity of cystathionine synthase for pyridoxal phosphate (B6)
3) Homocyteine methyltransferase deficiency

Question 7

Deficient branched chain alpha-ketoacid dehydrogenase

Leucine, valine, isoleucine and their ketoacids accumulate

Mental retardation, seizures, feeding problems, SWEET SMELLING URINE

Answer 7

Maple Syrup Urine Disease

Remember this: I Love Vermont maple syrup from maple trees with branches.

Question 8

Deficient phenylalanine hydroxylase

Phenylalanine accumulates (toxic)

Restrict Phe in food, add tyrosine to diet

Inborn error of metabolism?

Answer 8

PKU (Phenylketonuria)

If pregnant woman has PKU: Phe free diet is compulsory otherwise fetus will be mentally retarded

Question 9

Deficient Muscle glycogen phosphorylase (autosomal recessive)

Accumulation of glycogen

Glycogenosis, muscle fatigue, no lactic acid increase with exercise

MUSCLE CRAMPS and SPASMS during EXERCISE, myoglobinuria

Inborn error of metabolism?

Answer 9

McArdle’s Disease

McArdle = Muscle

Question 10

Deficient alpha-1,4,-glucosidase (lysosomal enzyme) (autosomal recessive)

Accumulation of glycogen

Cardiomegaly with early death (<2 yo)

Inborn error of metabolism?

Answer 10

Pompe Disease

Pompe trashed the Pump *heart, liver, muscle

Question 11

Deficient Glucose-6-phosphatase (gluconeogenic enzyme) (Autosomal recessive)

Glucose-6-phosphate accumulation

Glycogenosis, enlarged liver and kidneys, hypoglycemia (no response to glucagon)

NORMAL Mental development & Longevity

Inborn error of metabolism?

Answer 11

Von Gierke Disease

Question 12

Deficient glucocerebrosidase (Autosomal recessive)

Accumulation of glucocerebroside

Hepatosplenomegaly, Fibrillar-appearing macrophages in liver, spleen, and bone marrow, aseptic necrosis of femur, bone crises, pancytopenia

Inborn error of metabolism?

Answer 12

Adult type (Gaucher’s disease)

Question 13

Deficient a-L-Iduronidase

Accumulation of dermatan and heparan sulfate

Mental retardation, coarse facial and short neck

Inborn error of metabolism?

Answer 13

Hurler’s Syndrome

Question 14

Deficient Sphingomyelinase (Autosomal Recessive)

Accumulation of Sphingomyelin

Mental retardation, hepatosplenomegaly, foamy macrophages (lipid laden), hepatosplenomegaly, cherry red spot on macula

Inborn error of metabolism?

Answer 14

Niemann-Pick Disease

Question 15

Deficient Hexosaminidase A (Autosomal Recessive)

Accumulation of GM2, ganglioside

Muscle weakness, cherry-red macula, blindness, lysosomes with onion skin, NO Hepatosplenomegaly

Inborn error of metabolism?

Answer 15

Tay-Sachs disease

Question 16

You got this! Flip the card for a special surprise. Click the link! (It’s not porn, sorry)

Answer 16

https://www.youtube.com/watch?v=l-gQLqv9f4o

Question 17

Fibrillin-1 gene mutation (autosomal dominant)

CT disorder

Tall with long extremeties, pectus excavatum, hypermobile joints, long tapering fingers and toes (arachnodactyly)

Cystic medial necrosis of aorta (floppy mitral valve, aortic incompetence, and dissectinc AA)

Subluxation of lenses (Upward and temporally)

Syndrome?

Answer 17

Marfan Syndrome

Question 18

Neurocutaneous disorder

Numerous benign HAMARTOMAS: Harmartomas in CNS, Angiofibromas, Mitral regurgitation, Ash-leaf spots, cardiac Rhabdomyoma; Tuberous sclerosis, autosomal dOminant, Mental retardation, renal Angiomyolipoma, Seizures, Shagreen patches.

Increased incidence of subependymal astrocytomas and ungual fibromas

Incomplete penetrance, variable expression

Autosomal Dominant

Answer 18

Tuberous Sclerosis

Question 19

Cavernous hemangiomas in skin, mucosa, organs

bilateral renal cell carcinomas

hemangioblastoma (high vascularity with hyperchromatic nuclei) in retina, brain stem, cerebellum

pheochromocytoma

Autosomal dominant

Deletion of gene on which chromosome? Constitutive expression of what?

Answer 19

von Hippel-Lindau disease

VHL on Chromosome 3, expression of HIF resulting in activation of angiogenic growth factors

Question 20

What is this crazy First Aid mneumonic helping you remember?

Be Wise, Fool’s GOLD Heeds Silly HOpe

Answer 20

X-linked Recessive Disorders!

Bruton agammaglobulinemia

Wiskott-Aldrich syndrome

Fabry Disease

G6PD deficiency

Duchenne (and becker) muscular dystrophy

Hunter Syndrome

Hemophilia A &B

Ornithine transcarbamylase deficiency

Question 21

Mneumonic: Very Poor Carbohydrate Metabolism

Answer 21

VonGierke Disease

Pompe Disease

Cori disease (milder vonGierke, normal blood lactate in this)

McArdle Disease

Question 22

Deficient alpha-galactosidase A (X-linked Recessive)

Accumulation of ceramide trihexoside

Peripheral neuropathy of hands/feet

Angiokeratomas

Cardiovascular/renal disease

Answer 22

Fabry Disease