glycogen storage disease glycogen storage diseases are grouped of inherited disorders characterized...
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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.
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