Eric Niederhoffer, Ph.D. SIU-SOM

1. Year Two Review Part 2 Eric Niederhoffer, Ph.D. SIU-SOM

2. Pyrimidine and purine synthesis including salvage and degradation Glycogen storage disorders Lysosomal storage disorders Heme synthesis and degradation including oxygen binding/unloading of heme Integration of metabolism including lipid synthesis/degradation, glycolysis/gluconeogenesis, TCA cycle and glycogenolysis/glycogen synthesis Outline

3. Pyrimidine and Purine Synthesis HCO3- + Gln R5P CPSII RPK CP Asp PRPP Oro Gln UMPS Gly UMP N10fTHF CO2 UTP Asp CDP dCDP IMP dUMP GDP ADP N5,N10-mTHF TS RR dTMP dGTP dATP RNA DNA

4. Pyrimidine and Purine Salvage UTP CDP dCDP IMP dUMP N5,N10-mTHF TS GDP ADP RR dTMP RR dGTP dATP UMP TMP RNA DNA UTPT PRPP U T adenosine ADA HGPT inosine PNP A G PRPP HX XO APT urate X XO

5. Pathway Disorders Rare autosomal recessive disorders • UMP synthase – deficiency in either orotatephosphoribosyltransferaseor OMP decarboxylase leads to hereditary oroticaciduria, megaloblastic anemia appearing weeks to months after birth that does not respond to cobalamin, folic acid, or iron,oroticcrystalluria and nephropathy, cardiac malformations, strabismus, and recurrent infection. Urine orotic acid overexcretion. Enzyme assay of RBC. Treatment with oral uridine. • Adenosine deaminase– (Severe combined immunodeficiency disorder) variety of clinical phenotypes, history of infections, diarrhea, dermatitis, and failure to thrive,ribs and vertebrae abnormalities (defects in cartilaginous structures). Lymphopenia, B and T cell production affected. Enzyme assay of RBC/WBC. Treatment by bone marrow/stem cell transplantation or enzyme replacement. • Purine nucleotide phosphorylase– (Immunodeficiency)lymphopenia, thymic deficiency, recurrent infections, and hypouricemia, developmental delay, ataxia, or spasticity. T cell production affected. Enzyme assay of RBC, lymphocytes, fibroblasts. Treatment by bone marrow/stem cell transplantation. • Adenine phosphoribosyltransferase– frequent infections, renal colic, renal failure. Elevated urine levels of 2,8-dihydroxyadenine, 8-hyroxyadenine, and adenine; serum uric acid normal. Enzyme assay. Treated with dietary purine restriction, high fluid intake, and avoidance of urine alkalinization, Allopurinol to prevent oxidation of adenine.

6. Pathway Disorders X-linked recessive disorder • Hypoxanthine-guanine phosphoribosyltransferase– (Lesch-Nyhansyndrome) usually presents at 3 to 12 months with orange sandy urine precipitate, dystonia, intellectual disability, self-mutilation (lips, tongue, fingers), and gout. Elevated serum and urine uric acid levels. Enzyme assay on RBC, lymphocytes, fibroblasts. Molecular genetics of gene. Treated supportively with low-purine diet, allopurinol, and plenty of hydration.

7. Glycogen Storage Disorders GS GSD0 Glycogen transglycosylase branching enzyme GSDIV hPP GSDVI ls acid maltase GSDII UDP-Glc mPP GSDV G1P debranching enzyme GSDIII hG6Pase GSDI Glc G6P F6P PFK-1 GSDVII F16BP

8. Pathway Disorders Rare autosomal recessive disorders • Glycogen synthase –.(GSD type 0) fasting hypoglycemia, ketosis, especially before feeding. Periodic acid-Schiff stain shows decreased hepatic glycogen stores, muscle is normal.Treatment is appropriate diet to avoid hypoglycemia. • Glucose-6-phosphatase– (GSD type Ia, Von Gierke) history hypoglycemic seizures, hypotonia, hepatomegaly, xanthomas, manifestations of gout, hypertension, renal failure, and short stature. Fasting glucose, ischemic forearm test (negative), Enzyme assay. Treatment by high-protein diet, uncooked corn starch. • Lysosomal acid maltase – (GSD type II, Pompe, a-1,4-glucosidase); infantile - feeding and breathing difficulties, hypotonia, cardiomegaly; adult – limb-girdle weakness, respiratory muscle involvement. Hyperlipidemia, fasting ketonemia. Ischemic forearm test normal. Enzyme assay of fibroblasts. Periodic acid-Schiff stain is positive for lysosomal glycogen inclusions. Treatment by enzyme relacement, high protein diet. • Debranching enzyme – (GSD type III, Forbes-Cori, amylo-1,6-glucosidase), infantile seizures, hepatomegaly, growth retardation, progressive muscle weakness. Ischemic forearm test positive. Enzyme assay of fibroblasts. Periodic acid-Schiff stain is positive for basophilic glycogen deposits in all tissues. Treatment is supportive by corn starch, liver transplantation.

9. Pathway Disorders Rare autosomal recessive disorders • Branching enzyme –(GSD type IV, Andersen, transglucosidase) history not specific, hepatic failure, cirrhosis, hepatosplenomegaly, failure to thrive. Prenatal PCR and DNA analysis. Enzyme assay. Diffuse amylopectin-like deposits in the heart, liver, muscle, spinal cord, and peripheral nerves. Treatment is supportive with liver transplantation and diet. • Myophosphorylase– (GSD type V, McArdle) cramps, fatigue, and pain after exercise (depends on severity of deficiency), unique "second-wind" phenomenon. Ischemic forearm test positive. Enzyme assay. Periodic acid-Schiff stain gives subsarcolemmalblebs. Treatment by avoiding intense exercise, provide high protein diet. • Hepatic phosphorylase– (GSD type VI, Hers) most common among Mennonite religious group, also X-linked form, history of bulging abdomen, growth retardation, and slight delay in motor milestones, hepatomegaly. Enzyme assay on liver biopsy, RBC, WBC; molecular genetics of gene. Glycogen-distended hepatocytes, muscle normal. Treatment with dietary management as appropriate for clinical presentation. • Phosphofructokinase-1 – (GSD type VII, Tarui, M form, classic) history of exertional fatigue, nausea and vomiting, muscle cramps, hyperuricemia, myoglobinuriafollowing high-intensity exercise. Ischemic forearm test positive. Enzyme assay on muscle biopsy. Periodic acid-Schiff diastase-negative stain gives subsarcolemmalblebs. Treatment to avoid high carbohydrate diet especially before exercise.

10. Lysosomal Storage Disorders • Lipid metabolism • Landing, Sandhoff, Tay-Sachs, Krabbe, Gaucher, Niemann Pick (A,B), Wolman, metachromatic leukodystrophy, Fabry • Glycoprotein metabolism • Schindler • Mucopolysaccharide metabolism • Hurler/Scheie, Hunter, Sanfilippo (A,B,C,D), Morquio (A,B), Maroteaux–Lamy, Sly • Other lysosomalenzymes • Pompe, Niemann-Pick (C)

11. Oligosaccharidoses a-Mannosidosis a-Mannosidase GM2gangliosidosis variant O (Sandhoff-Jatzkewitz disease) b-N-Acetylhexosaminidases A&B Aspartylglycosylaminuria 4-L-Aspartylglycosylamine amidohydrolase 5 6 4 NANA Gal GlcNAc a b Man b 6 5 3 NANA Gal GlcNAc 4 b a a 7 2 1 Man GlcNAc GlcNAc Asn 5 6 a NANA Gal GlcNAc 4 3 b b 8 b a Man b GlcNAc Fuc 5 6 NANA Gal GlcNAc 4 a b Typical Asn-GlcNAc OS structure b-Mannosidosis GM1gangliosidosis b-Mannosidase b-Galactosidase Fucosidosis Mucolipidosis I (Sialidosis) a-Fucosidase Sialidase

12. Glycosaminoglycoses(mucopolysaccharidoses) Mucolipodosis VII Sanfilippo’s A Hunter’s b-glucuronidase iduronatesulfatase heparanN-sulfatase Hurler-Scheie Aldurazyme® (laronidase) a-L-iduronidase Sanfilippo’s C Maroteaux-Lamy Acetyl-CoA: a-glucosaminideacetyltransferase N-acetylgalactosaminesulfatase 2 4 5 GalNAc GlcUA GalNAc DS IdUA a b b b 1 3 OSO3H OSO3H OSO3H 2 7,9 5 9 GlcNAc HS GlcN GlcUA IdUA a a a b 1 6 8 OSO3H OSO3H OSO3H Sandhoff/Tay-Sachs Sanfilippo’s B N-acetylglucosaminidase b-hexosaminidase A,B,S 11 4 Gal KS Gal GlcNAc GlcNAc b b b b 10 8 OSO3H OSO3H OSO3H Morquio’s A Sanfilippo’s D N-acetylgalactose-6-sulfatase N-acetylglucosamine-6-sulfatase Morquio’s B b-galactosidase

13. b b b b a Cer Glu Gal Cer Glu Gal Gal b-galactosidase SAP-B, SAP-C b Cer Glu b b b a Cer Glu Gal Gal GalNAc b Cer PC Cer Cer Gal b Cer Gal SO3H S + FA Gangliosidoses neuraminidase (sialidase) NANA Generalized gangliosidosis NANA b-galactosidase b b b b GD1 Gal GalNAc Gal Cer Glu NANA b b b b GM1 Cer Glu Gal GalNAc Gal NANA Tay-Sachs disease b-hexosaminidase A GM2 activator b b b Cer Glu Gal GalNAc GM2 NANA Sialidosis neuraminidase (sialidase) SAP-B b b GM3 Cer Glu Gal Fabry’s disease a-galactosidase A SAP-B Sandhoff’s disease b-hexosaminidase A&B Gaucher’s disease b-glucosylceramidase SAP-C Krabbe’s disease Cerezyme b-galactosylceramidase SAP-A, SAP-C Metachromatic leukodystrophy Niemann-Pick disease arylsulfatase A SAP-B sphingomyelinase

14. General Physical Features • Coarse facial features (sometimes with macroglossia) • Corneal clouding or related ocular abnormalities • Angiokeratoma • Umbilical/inguinal hernias • Short stature • Developmental delays • Joint or skeletal deformities • Organomegaly(especially liver and spleen) • Muscle weakness or lack of control (ataxia, seizures, etc.) • Neurologic failure/decline or loss of gained development

15. Heme Synthesis mit SCoA + Gly 5AS PBGS PBG 5ALA PBGD Heme HMB FC UPGIIIS PPIX UPGIII UPGIIIDC PPGO CPGO CPGIII PPGIX

16. Pathway Disorders • PBG synthase– (5-aminolevulinic acid dehydratase) extremely rare autosomal recessive (hepatic porphyria) neurological findings, abdominal tenderness, neuropathy, not associated with cutaneous photosensitivity. Elevated urine ALA, coproporphyrin III and protoporphyrin IX, normal PBG, elevated RBC zinc protoporphyrinbut decreased (80%) PBG synthase. DNA analysis. Treatment by avoiding precipitating factors, drugs that induce P450 induction, provide hematin, high carbohydrate diet (glucose inhibits 5-AS). • PBG deaminase– (Acute intermittent porphyria) autosomal dominant, abdomen pain, psychiatric symptoms (hysteria), motor neuropathies (more commonly lower limbs), and constipation but no skin rash. Increased urinary porphobilinogensecretion, molecular genetic analysis. Treatment during attacks with high carbohydrate (glucose) diet and hematin, otherwise, balanced diet. • Uroporphyrinogen III synthase – (Congenital erythropoetic porphyria, Gunther disease) rare autosomal recessive, photosensitivity, nail abnormalities, brown or pink teeth. Elevated urine and RBC levels of uroporphyrin I, hemolytic anemia. Enzyme assay, molecular genetic analysis, red porphyrin fluorescence in intact RBC and erythroid precursor cells. Treated with absolute avoidance of sun exposure, supportive/cosmetic care. • Uroporphyrinogen III decarboxylase – (Porphiacutanatarda) 80% acquired/20% familial/autosomal dominant, acquired by ethanol abuse, estrogen therapies, hemochromatosis genes, hepatitis and human immunodeficiency viral infections, environmental toxins, photosensitivity, tea/wine colored urine. Carboxylatedporphyrins in serum and urine. Enzyme assay of RBC, molecular genetic analysis. Treatment with avoidance of sunlight/environmental exposure.

17. Pathway Disorders • Coproporphyrinogen oxidase – (Hereditary coproporphyria) autosomal dominant, abdominal pain, neuropathies (motor, lower limbs), constipation, and skin changes (photosensitivity). Excess secretion and levels of coproporphyrinsin stool and urine. Treatment with high carbohydrate (glucose) diet and hematin. • Protoporphyrinogen oxidase – (Variegate porphyria) autosomal dominant, photosensitivity, abdominal discomfort. Urinary aminolevulinic acid and porphobilinogen levels are greatly elevated during attacks, molecular genetic analysis. Treatment with avoidance of inducing drugs, providing high carbohydrate diet, hematin. • Ferrochelatase – (Erythropoeticprotoporphyria) autosomal dominant (X-linked, autosomal recessive), photosensitivity, heptabiliary disease, jaundice. Elevated protoporphyrin concentration in red blood cells, plasma, bile, and feces. Treatment with avoidance of sun exposure, maintain balanced diet.

18. Heme Degradation res indirect unconjugated pre-hepatic HO BVR Heme BV BR albumin albumin-BR albumin ligandin hepatocyte ligandin-BR UDP-GT ER BR diglucuronide direct conjugated post-hepatic

19. Pathway Disorders Autosomal recessive disorders • UDP-glucuronyltransferase– mild deficiency (Gilbert syndrome) most common inherited cause of unconjugated hyperbilirubinemia, intermittent jaundice without hemolysis or liver disease, precipitated by dehydration, fasting, menstrual periods, intercurrentillness, trauma, over exertion, nonspecific symptoms such as abdominal cramps, fatigue, and malaise, mild jaundice. Unconjugated hyperbilirubinemia (by definition [bilirubin] < 6 mg/dL, commonly < 3 mg/dL), normal complete blood count, reticulocyte count, and blood smear, normal liver function panel. Treatment is reassurance and avoiding precipitating factors. • UDP-glucuronyltransferase – severe deficiency (Crigler-Najjar syndrome) rare, types 1 and 2 (Arias syndrome). Type 1 almost complete deficiency associated with neonatal unconjugated hyperbilirubinemia(17-50 mg/dL) and kernicterus, hypotonia, deafness, oculomotor palsy, lethargy. Type 2 deficiency unconjugated bilirubin (6-20 mg/dL), persistent jaundice at birth or after. Elevated unconjugated bilirubin with normal liver function panel. Phenobarbital treatment distiguished type 1 (no effect) from type 2 (lowers serum bilirubin 25%). Treatment of bilirubin encephalopathy with plasma exchange transfusion and long-term phototherapy.

20. Integration of Metabolism • SSB • metabolism in brain, nervous tissue and muscle • alcohol processing and effect on metabolic pathways • vitamins in neuromuscular metabolism • ERG • regulation of metabolism and diabetes