GLYCOGEN STORAGE
DISORDERS
These are a group of inherited disorders
associated with glycogen metabolism,
familial in incid...
There are 6 classical types of glycogen
storage diseases


Type1)Von gierke’s disease
Type2)Pompe’s disease

Type3)Limit ...
TYPE 1:Von gierke’s disease

 ENZYME DEFICIENCY :glucose-6phosphatase
 INHERITANCE : Autosomal recessive
 Liver cells a...
CLINICAL AND BIOCHEMICAL FEATURES OF VON
GIERKE’S DISEASE

 Only little amount of glucose is available is derived
from li...
Cont….
 Increased fatty acid synthesis can produce fatty
infiltration of liver
 PERSISTENT HYPOGLYCAEMIA has 2 effects
H...
PROGNOSIS
Children with this disease
may die young and some
of them survive till
adolescence
TYPE 2: POMPE’S DISEASE

 ENZYME DEFICIENCY : ACID MALTASE enzyme
which is present in lysosome and catalyses the
breakdow...
CLINICAL FEATURES
 Enlargement of heart (cardiomegaly)
 Muscle weakness
PROGNOSIS

 Infants usually die due to cardiac failure and broncho
pnuemonia
 Death usually occurs before 9 months
TYPE 3 : LIMIT DEXTRINOSIS(FORBE’S
DISEASE)

 ENZYME DEFICIENCY : DEBRANCHING ENZYME
 INHERITANCE : AUTOSOMAL RECESSIVE
...
CLINICAL AND BIOCHEMICAL FEATURES

•
•
•
•
•

HEPATOMEGALY
MODERATE HYPOGLYCEMIA
ACIDOSIS
PROGRESSIVE MYOPATHY
Enzyme defi...
PROGNOSIS

 Survives well to adultlife
TYPE 4 : AMYLOPECTINOSIS(ANDERSON’S
DISEASE)

 ENZYME DEFICIENCY : BRANCHING ENZYME
 INHERITANCE : NOT DEFINETELY KNOWN
...
CLINICAL AND BIOCHEMICAL FEATURES

 HEPATOMEGALY
 SPLENOMEGALY
 MODERATE HYPOGLYCEMIA

 NODULAR CIRRHOSIS OF LIVER
 H...
PROGNOSIS

 Usually fatal
 Longest survival is reported as 4 years
TYPE 5 : McArdle’s disease
 ENZYME DEFICIENCY : MUSCLE PHOSPHORYLASE
 INHERITANCE : AUTOSOMAL RECESSIVE
 Glycogen depos...
CLINICAL FEATURES

Muscle cramps on exercise

Pain
Stiffness and weakness of muscles
EPINEPHRINE TEST
 After administration of epinephrine rise in
blood glucose occurs which shows that
hepatic phosphorylase...
TYPE 6 : Her’s disease

ENZYME DEFICIENCY : LIVER
PHOSPHORYLASE
Glycogen deposited is normal in
structure

Organs affec...
CLINICAL AND BIOCHEMICAL FEATURES

 HEPATOMEGALY
 MODERATE HYPOGLYCEMIA
 MILD ACIDOSIS
GLYCOGEN STORAGE DISORDERS
GLYCOGEN STORAGE DISORDERS
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Transcript of "GLYCOGEN STORAGE DISORDERS"

  1. 1. GLYCOGEN STORAGE DISORDERS These are a group of inherited disorders associated with glycogen metabolism, familial in incidence and characterized by deposition of normal or abnormal type and quantity of glycogen in the tissues
  2. 2. There are 6 classical types of glycogen storage diseases  Type1)Von gierke’s disease Type2)Pompe’s disease Type3)Limit dextrinosis(Forbe’s disease) Type4)Amylopectinosis(anderson’s disease) Type5)McArdle’s disease Type6)Her’s disease
  3. 3. TYPE 1:Von gierke’s disease  ENZYME DEFICIENCY :glucose-6phosphatase  INHERITANCE : Autosomal recessive  Liver cells and intestinal mucosal cells are fully loaded with glycogen and metabolically unavailable
  4. 4. CLINICAL AND BIOCHEMICAL FEATURES OF VON GIERKE’S DISEASE  Only little amount of glucose is available is derived from liver  So the children with this disease may tend to develop hypogycemia  Fat is used as a energy source so it may lead to LIPAEMIA,ACEDEMIA and KETOSIS  Excess of Acetyl coA is diverted for chosterol synthesis this may lead to elevated level of cholestrol and results in XANTHOMAS
  5. 5. Cont….  Increased fatty acid synthesis can produce fatty infiltration of liver  PERSISTENT HYPOGLYCAEMIA has 2 effects Hypoglycemia inhibits insulin which in turn inhibits protein synthesis which results in DWARFISM Hypoglycemia stimulates the secretion of CATECHOLAMINES which cause muscle glycogen to break down producing lactic acid and LACTIC ACIDOSIS  Increased blood lactic acid competes with urate excretion by kidneys leading to increased blood uric acid levels  Children with increased uric acid synthesis may develop the symptoms of GOUT
  6. 6. PROGNOSIS Children with this disease may die young and some of them survive till adolescence
  7. 7. TYPE 2: POMPE’S DISEASE  ENZYME DEFICIENCY : ACID MALTASE enzyme which is present in lysosome and catalyses the breakdown of oligosaccharides  INHERITANCE : AUTOSOMAL RECESSIVE  Here the glycogen structure is normal and the organs which are involved is HEART,LIVER,SMOOTH MUSCLE,AND STRAITED MUSCLE  All the tissue contain excess of glycogen
  8. 8. CLINICAL FEATURES  Enlargement of heart (cardiomegaly)  Muscle weakness
  9. 9. PROGNOSIS  Infants usually die due to cardiac failure and broncho pnuemonia  Death usually occurs before 9 months
  10. 10. TYPE 3 : LIMIT DEXTRINOSIS(FORBE’S DISEASE)  ENZYME DEFICIENCY : DEBRANCHING ENZYME  INHERITANCE : AUTOSOMAL RECESSIVE  GLYCOGEN STRUCTURE : LIMIT DEXTRIN TYPE  Organs involved are heart liver and muscle
  11. 11. CLINICAL AND BIOCHEMICAL FEATURES • • • • • HEPATOMEGALY MODERATE HYPOGLYCEMIA ACIDOSIS PROGRESSIVE MYOPATHY Enzyme deficiency can be demonstrated in leucocytes
  12. 12. PROGNOSIS  Survives well to adultlife
  13. 13. TYPE 4 : AMYLOPECTINOSIS(ANDERSON’S DISEASE)  ENZYME DEFICIENCY : BRANCHING ENZYME  INHERITANCE : NOT DEFINETELY KNOWN  Glycogen deposited is abnormal type, few branch points and very long inner and outer unbranched chains  LIVER is the mainly affected organ and other organs are HEART, KIDNEY, and MUSCLES  Deposition is seen in RE SYSTEM
  14. 14. CLINICAL AND BIOCHEMICAL FEATURES  HEPATOMEGALY  SPLENOMEGALY  MODERATE HYPOGLYCEMIA  NODULAR CIRRHOSIS OF LIVER  HEPATIC FAILURE  Enzyme deficiency can be demonsrated in leucocytes and liver
  15. 15. PROGNOSIS  Usually fatal  Longest survival is reported as 4 years
  16. 16. TYPE 5 : McArdle’s disease  ENZYME DEFICIENCY : MUSCLE PHOSPHORYLASE  INHERITANCE : AUTOSOMAL RECESSIVE  Glycogen deposited in normalstructure and the organs involved are skeletal muscles
  17. 17. CLINICAL FEATURES Muscle cramps on exercise Pain Stiffness and weakness of muscles
  18. 18. EPINEPHRINE TEST  After administration of epinephrine rise in blood glucose occurs which shows that hepatic phosphorylase activity is normal
  19. 19. TYPE 6 : Her’s disease ENZYME DEFICIENCY : LIVER PHOSPHORYLASE Glycogen deposited is normal in structure Organs affected are mainly LIVER and LEUCOCYTES
  20. 20. CLINICAL AND BIOCHEMICAL FEATURES  HEPATOMEGALY  MODERATE HYPOGLYCEMIA  MILD ACIDOSIS

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