CASE 1

A male infant is born without complications and appears normal until 1 year of age, when he has trouble standing. By age 2, he exhibits severe ataxia and psychomotor retardation. He cannot stand or walk, and he speaks very little. Urinalysis reveals high levels of alanine. Blood tests reveal elevated levels of pyruvate and lactate. Therapeutic doses of thiamine are administered, and within 6 months the boy can walk and speak.

1. What is the most probable enzyme defect in this condition? Explain your answer.2. Why are pyruvate, alanine, and lactate elevated in this case?3. Why did therapeutic doses of thiamine correct this problem?4. What other enzyme could be affected by a deficiency in thiamine?5. If thiamine supplementation were discontinued, will there be a recurrence of the symptoms? Why?6. In the Philippines, can this disease be detected through routine newborn screening?7. What other treatments can be given to this patient aside from thiamine?

CASE 2

A 20-year-old man is admitted to the hospital with painful swelling, cramping, and tightness in his arms. The symptoms began after lifting and carrying heavy objects while moving into a new apartment. Since childhood, he has experienced cramping of muscles after strenuous exercise, and he has routinely experienced weakness of continuously used muscles. No enlargement of the liver is apparent, and blood sugar levels are normal. Liver function tests did not reveal any abnormalities. Imaging studies on the spleen and kidney also revealed normal findings. A muscle biopsy is performed, and histochemical studies reveal excessive deposition of glycogen in the muscle. On liver biopsy, no excessive glycogen deposition was apparent.

1. What specific disease is this man suffering from?2. What is the most possible enzyme defect?3. Why was the disease not manifested during the patient's childhood years?4. Why was the liver unaffected?5. What is the treatment for this case?6. Will eating carbohydrate-rich foods prior to anticipated physical exertion be helpful in this case? Why?7. Is this disease fatal? Why or why not? CASE 3

A male infant appears normal at birth but, when breastfed, exhibits vomiting and diarrhea and an overall failure to thrive. At 5 days of age, he begins to exhibit mild jaundice. Analysis of the infant's urine shows the presence of sugar, but not glucose as indicated by

a glucose oxidase assay. The same sugar was found in the urine and serum on further analysis.1. What sugar may have accumulated in the serum and urine of this patient?2. Could the liver possibly be affected in this case? Why do you say so?3. What enzyme would probably be deficient in this case? Could this enzyme defect be detected by newborn screening in the Philippines?4. Can breastmilk be given to this infant? Why or Why not?5. Will the infant outgrow this enzyme deficiency when he grows up?6. How is the sugar found in the serum and urine of this patient metabolized or broken down by the body?

CASE 4

A 30-year-old man presents with evidence of coronary heart disease and xanthomas in the tendons. Blood analysis shows a serum cholesterol level of 420 mg/dL and a triglyceride level of 75 mg/dL. The patient was given lovastatin and colestipol, and after 15 months of treatment, his condition was markedly improved.

1. What is your diagnosis for this case?2. What is the basis for the treatment given? Give the mechanism of action of both treatments mentioned.3. Will diet therapy be helpful in this patient? If diet therapy would help, what type of diet would be beneficial in this case?4. What lipoprotein would you expect to be elevated in the patient prior to initiation of treatment?5. During treatment, would supplementation with Coenzyme Q benefit this patient? Why or why not?6. Will administration of carnitine help in treating this patient? Why or why not?7. What diseases were prevented by the timely and early treatment of this case?

CASE 5

An infant is born without complications but becomes extremely lethargic and begins to hyperventilate beginning 24 hours after birth. Blood analysis indicates a below-normal Blood Urea Nitrogen (BUN) level, a slightly alkaline pH, and a below-normal level of partial pressure of carbon dioxide (PCO2). A chest radiograph is normal. Further blood analysis reveals a high level of glutamine, and no detectable citrulline. Urinalysis reveals high levels of orotic acid. The infant is given a blood transfusion and hemodialysis immediately. This is followed by intravenous administration of sodium benzoate and phenylacetate.

1. What metabolic process is affected in this case2. What enzyme is probably deficient in this case?3. With the low levels of PCO2, is the patient suffering from acidosis or alkalosis? 4. What toxic substance is expected to accumulate in the blood of this patient?

5. Why was BUN low in this case? Is this probably due to a kidney problem? Why or why not?6. What is the rationale for administering sodium benzoate and phenylacetate?7. What dietary modification is needed to reduce the patient's symptoms? Why must this diet be carried out?