LEC 41 & 42

Question 1

What are Type 1 IEMs?

Answer 1

• Disorders of intermediary metabolism (sm molecules)
• Disorders resulting in acute/progressive intoxication from accumulation of toxic compounds proximal to metabolic block (PKU, Hereditary Fructose Intolerance, Urea Cycle Defects, MSUD)
  These disorders are TREATABLE (ie: special diet)

Question 2

What are Type 2 IEMs?

Answer 2

Disorders of energy metabolism
* features due at least in part to deficient energy production/utilization within tissue/organs (Mitochondrial respiratory chain disorders, Disorders of glycolysis, fatty acid oxidation disorders)

Question 3

What are Type 3 IEMs?

Answer 3

• Disorders involving Complex Molecules
• Diseases involving cellular organelles that disturb synthesis or catabolism of complex molecules (Lysosomal storage diseases, peroxisomal diseases)

Question 4

What is Neu-Laxova syndrome?

Answer 4

Serine synthesis defect (nonessential compound)
* severe fetal growth
* microcephaly
* distinct facial appearance
* Ichthyosis (scaly “fish” skin)
* Skeletal abnormalities
* perinatal lethality
Treat w/ serine supplementation

Question 5

What is Menkes disease?

Answer 5

Copper transporter disease (metal transport defect)
* alopecia
* steely hair (steel wool)
* rare eyebrows
* sagging cheeks
* hypopigmentation
* pili torti
* trichorrexis nodosa
* hypotonia, hypothermia

Question 6

What is the Keyser-Fleisher ring?

Answer 6

a deep copper-colored ring at the periphery of the cornea which is frequently found in Wilson disease and is thought to represent copper deposits

Question 7

What are the clinical manifestations of Smith-Lemli-Opitz (SLO)?

Answer 7

• “SLO face” consists of microcephaly, bitemporal narrowing, ptosis, short nasal root, anteverted nares, and small chin
• Cleft palate
• Polydactyly and syndactyly (2nd & 3rd toe fusion)
• Genital anomalies: hypospadias, cryptorchidism
• CNS anomalies: Microcephaly, holoprosencephaly, enlarged ventricles, absence of the corpus callosum

Question 8

What enzyme is deficient in SLO?

Answer 8

3B-hydroxycholesterol-7-reductase

converts 7-dehydroxycholesterol to cholesterol

Question 9

What 2 compounds must be collected from a free flowing vein with no tourniquet and kept on ice and analyzed immediately?

Answer 9

• Ammonia
• Lactate

Question 10

What are the clinical manifestations of Zellweger syndrome?

Answer 10

• Hypotonia
• Poor feeding
• Very bad development
• Seizures
• Hepatic cysts with liver dysfunction
• Retinal dystrophy
• Sensorineural hearing loss
• Death often within first year of life

Question 11

What are some characteristics & examples of mitochondrial diseases (IE of energy metabolism)?

Answer 11

defects in mito. or nuclear DNA
Characteristics: stroke, exercise intolerance, diabetes mellitus, cardiomyopathy
Examples: Leigh syndrome, Pyruvate Dehydrogenase deficiency