disorders of cho metabolism

7/25/2019 Disorders of Cho Metabolism

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DISORDERS OF CHO METABOLISM

Disorder Deficiency Description Pathophysiology Clinical Features Diagnosis

GALACTOSEMIA GALT

(Galactose-1-Phosphate

Uridyltransferase)

GALK (Galactokinase)

GALE

(UDP-Galactose-4-

epimerase)

Abnormal accumulation of

galactose and gal-1-p in

brain, liver, kidneys

Galactitol (lens of eyes)

AUTOSOMAL RECESSIVE

1:10,000 to 1:30,000

Develop soon after intake of

lactose on 3rd

-rth day of life

Vomiting, Diarrhea, Failure to

thrive, Hepatomegaly,

Neonatal jaundice. Cataracts

Liver failure

Kidney Failure

E. coli Sepsis

First milk feeding provokes:

- Failure to thrive

-

Vomiting & Diarrhea

- Jaundice and

Hepatomegaly

- Mental Retardation

- Renal Fanconi Syndrome

Presence of reducing

substances in urine

Enzyme Assay in RBC, cord

blood and cultured

fibroblast

Measurement of

erythrocyte GALT activity

Molecular genetic testing

Newborn:

Vomiting, Hepatomegaly,

Cataracts

Ca

ga

re

re

3

Ex

di

Su

co

w

so

Ca

m

if

m

GLYCOGEN STORAGE

DISEASES

Result from enzymatic

deficiencies involved in

either the breakdown or

synthesis of glycogen

Glycogen accumulation or

formation of abnormal

glycogen structures

Liver:

GSD1, 3, 4, 6

Muscles:

GSD 5, 7, 10, 11, 12, 13

Both:

GSD 0 and 9

GeneralizedGlycogenolysis: GSD 2

1:20,000 to 1:25,00 birth Biochemical Abnormalities:

- Elevated blood

lactate

-

Pyruvate

-

Uric Acid

-

Cholesterol

-

TGC

Von Gierkes Disease Glucose-6-Phosphate

Alpha System

AUTOSOMAL RECESSIVE

Classical GAL (GALT Deficiency)

oUntreated

oNeonatal onset: multiple

systems

oLiver dysfunction,

coagulopathy, feeding and

weight loss, vomiting, lethargy

and hypotonia, renal

dysfunction,encephalopathy,

hemorrhage, E. coli sepsis

oCataracts

oOvarian failure (90%)

oChronic brain effects (global

deficits, disability, etc.)

GALK deficiency:

oCataracts and galactosemia

in otherwise healthy

Massive Hepatomegaly

Fasting Hypoglycemia

Lactic Acidosis

Physical features:

-

Short stature

-

Doll-like facies

-

Protuberant

abdomen

-

Lumbar lordosis

Complications: Renal Disease

and Liver Adenomas

Detection

- Detection of increased

Gal-1-P metabolites

-

Enzyme studies (in serum,

-

-

-

-

-

-


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Epimerase deficiency:

o Partial deficiency

o Rarely, presents similarly

with GALT but with increase

or normal GALT enzyme

RBC)

- DNA mutation analysis

(research basis at

present)

Pompe Disease Lysosomal Acid Maltase

1,4 glucosidase(GAA)-

enzyme responsible for

glycogenolysis in

liposomes

AUTOSOMAL RECESSIVE accumulation of excess glycogen

in nearly all cells

heart, muscles and nervous

tissue are predominantly

affected

profound hypotonia withprogressive muscle weakness

but with normal mentation

hypoglycemia and ketosis are

absent

cardiomyopathy and respiratory

difficulties are common in

infantile form

walking difficulties in late and

juvenile forms

individuals are not mentally

retarded

Clinical Phenotypes:

Infantile-onset PD (IOPD)

severe hypotonia,

hepatomegaly,

hypertrophic

cardiomyopathy barely survive beyond

toddler age

GAA activity: typically


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disorders of cho metabolism

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