#Biochemistery
#Carbohydrate_metabolism
#بوست_رقم (13)
في البوست ح نتكلم عن
glycogen storage diseases
🌸Glycogen storage diseases (GSDs):
These are a group of inherited disorders associated with glycogen metabolism, familial in incidence and characterised by deposition of normal or abnormal type and quantity of glycogen in the tissues.
🌸 Causes:
They are mainly due to deficiency of one of enzymes of glycogen metabolism.
🌸 Types: (8 types):
🍁Type "1" ( von Gierk's disease):
☘Enzyme deficiency: Glucose-6-phosphatase.
☘Inheritence: Autosomal recessive.
☘It is characterized by:(clinical feature):
1. Accumlation of large amount of glycogen in liver
ودا ح يخلي لي الكبد م تقدر تقوم ب ال Functions بتاعتها.
2. Hepatomegally (enlargement of liver).
3. Fasting hypoglycemia: can two effects:
1. Hypoglycemia inhibits insulin,which inhibits protein synthesis which cause dwarfism (التقزم)
2. Hypoglycemia stimulates secretion of catecholamines, which cause muscle glycogen to breakdown producing lactic acid and lactic acidosis.
4. Ketosis and hyperlipidemia because increase fat utilised as source of energy, and increase cholesterol level.
5. Increase FA synthesis can produce fatty infiltration of liver.
6. Hyperuricemia (gout):
يلا نشوف هنا كيف بحصل لينا gout
لما يزيد تنافس ال blood lactic acid مع urate excretion by kidneys دا بقودني ل زيادة في blood uric acid level ودا هو اللي بيتسبب لي في gout.
🌸Type II (pome's disease):
☘ Enzyme deficiency: acid maltase ,present in lysosome and catalyses breakdown of oligosaccharides.
☘ Inheritance: Autosomal recessive.
☘ Glycogen structure: normal.
☘clinical feature:
1. Cardiomegaly ( enlargement of heart).
2. Muscle weakness.
3. No hypoglycemia.
☘ Prognosis: (تطور المرض )
Infant usually die of cardiac failure and bronchopneumonia.
Death usually occurs before 9 months,few cases milder from up to 2½ years.
🌸 Type III limit Dextrinosis (Forbe's disease) (cori's disease):
دي كلها اسماء لل disease دا
☘ Enzyme deficiency: Debranching enzyme in liver,muscles and heart.
☘ Glycogen structure: abnormal ,short or missing outer chains.
☘clinical feature:
1. Hepatomegaly.
2. Moderate hypoglycemia.
3. Acidosis.
4. Progressive myopathy.
نفس فهم type I بس الاختلاف انه دا بكون فيه ال Glycogen abnormal .
☘ Prognosis:
Survives well to adult life.
🌸 Type IV: Amylopectinosis (Andersen's disease):
☘Enzyme deficiency: Branching enzyme.
☘ Inheritence: Not definitely known.
☘ Glycogen structure: abnormal, few branch points and very long inner and outer unbranched chains
يعني بكون مافي او لو في بكميات قليلة لل branches وبكون بشبه ال amylopectin عشان كدا سموا ال disease بالاسم دا.
طيب هو شنو ال amylopectin دا عبارة عن
water-soluble polysaccharides and highly branched polymer of α-glucose units found in plants. It is one of the two components of starch, the other being amylose.
بس بختلف عن ال Glycogen انه م فيه branches كتيرة.
الصورة تحت عشان يوضح ليكم ال structure بتاعو👇.
☘ Main organs affected are: liver (mainly), heart,muscle and kidney.
☘ clinical feature:
1. Hepatomegaly and splenomegaly
ممكن نقولهم كدا الاتنين مرة واحدة ونقول hepatosplenomegaly.
2. Ascites. (استسقاء)
يعني تتراكم لي السوائل في ال peritoneum (غشاء رقيق كدا في البطن) عشان كدا بكون في انتفاخ في البطن.
3.moderate hypoglycemia.
4. Nodular cirrhosis of liver and hepatic failure.
☘ Prognosis:
Usually fatal, longest survival reported as 4 years.
🌸 Type V: McArdle's disease:
☘ Enzyme deficiency: Muscle phosphorylase only but hepatic phosphorylase activity is normal.
☘ Glycogen structure: normal.
☘ Organ involved: skeletal muscle.
☘clincial feature:
1. Muscle cramps on exercise.
2. Pain, weakness and stiffness of muscles.
★ Muscles recoveron rest,due to utilized FA for energy.
🌸 Type VI: Her's disease:
☘Enzyme deficiency: liver phosphorylase.
☘ Glycogen structure: normal .
☘ Organs involved: mainly liver and also leucocytes.
☘clinical feature:
1. Hepatome
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