Glycogen storage disease

Glycogen storage diseases are grouped of inherited disorders characterized by deposition of an abnormal type or quantity of glycogen in the tissues.

They are mainly due to deficiency of one of enzyme of glycogenolysis or glycogenesis.

Type I

Von Gierke’s diseaseIt is due to deficiency of glucose -6-

phosphatase in liver and kidnney.It is commonest type Accumulation of large amount of glycogen

glycogen in liver – disturbance in liver function.

Enlargement of liver and kidney.Fasting hypoglycemia associated with ketosis

and hyperlipaemia.

Type II

Pompe’s disease Deficiency of acid maltase.Glycogen accumulation in lysosome.

Type III

limit dextrinosis disease(cori disease).

Due to deficiency of debranching enzyme of in liver ,muscles and heart.

Glycogen has many short branches.

Type IV

Amylopectinosis(anderson’s disease)Due to absence of branching

enzyme .glycogen formed have no or few branches.

Type V

Mc –Ardle’s disease.Due to muscle phosphorylase . Glycogen

is accumulated in muscle and breaking does not occur during exercise.

Muscle cramps are present.

Type VI

Her’s diseaseDue to deficiency of liver phosphorylase.

Type VII

Due to deficiency of phosphofructokinase enzyme in the muscle.

Fructosaemia

Hereditary deficiencyAldolase –B enzyme accumulation of

fructose 1- PFrcutose 1,6 –biphosphatase

accumulation of fructose 1,6 biphopate (hereditary fructose intolerance).

Accumulation of F -1-P and F -1 , 6BPinhibiton of glycogen phosphorylase inhibition of glycogenolysis liver glycogen + hypoglycemia.

Fructosuria

Appearance of fructose in urine . It is a result of fructosaemia.

Conversion of glucose to fructose: Free fructose found in semen and amniotic

fluidDeficiency of fructose in seminal fluid

correlates with male infertility.Derived from conversion of glucose to

fructose.Formed in the seminal fluid vesicle as follows:

As follows

Glucose ALDOSE REDUCTASE sorbitol sorbitol dehydrogenase fructose

NADPH + H+ NADP+ NADH+ NADH + H+

galactosaemia

Increase of galactose concentration in blood.Causes: It is due to deficiency of one of the

following enzyme : Galacotokinase , galactose 1 uridyl transferase and UDP-galactose epimerase.

Pathological effects:Cataract : ( opacity of the eyes lens)Galactose reduced by aldose reductase galactitol cataract l

Cont.

Liver failureMental retardationGalactosuria: increase excretion of

galactose in urine.

Hyperglycemia

Rise in blood glucose level above normal average concentration.equal or more than 140mg/dl.

Occurs inDiabetes mellitusPatient receiving intravenous fluid

containing glucose.Temporarily in severe stress.After cerebrovascular accidents.

hypoglycemia

Decrease in blood glucose level below normal average concentration : less than 40mg/dl.

Symptoms:Release of acute adrenaline which leads to 1. Sweating ,weakness, anxiety,

nervousness and hunger.

Ketosis coma

Due to acidosis(ketosis)

DDM

Insulin –dependent (or type I) diabetes mellitus (DDM)

Absolute deficiency of insulin caused by destruction of Beta cells of the pancreas .

stimulus form environment( viral infection)

Autoimmune condition called insulinitis“Honey moon” transient condition.ketosis

Type II

Most common Non-insulin dependent diabetes

mellitus(NIDDM).Develops without any symptoms.Dysfunction of Beta cells Resistance to insulin action at cellular level.NIDDM is based on completely genetic

background. No virus or autoimmune antibodiesOver 80% of NIDDM are obese.

Bronze diabetes

Caused by excessive absorption of iron and its precipitation in tissues as:

1. skin: causing discolouration.2. causing diabetes mellitusLiver : causing hepatic cirrhosis.

Lactic acidosis

Due to hyperlactatemia .This type may occur in some patients who receive oral hypoglycemia drug called : phenformin.