 Clinical chemistry, chemical pathology and medical biochemistry  is the area of clinical pathology that is generally concerned with analysis of bodily fluids.  Originated in the 19 th century with simple chemistry test of blood and urine

 Disorders of Protein Metabolism:  Non-protein nitrogenous compounds (Urea, uric acid & amino acids): 3 lectures › Their normal plasma levels › Disease states associated with their increased and decreased levels in the plasma.  Plasma Proteins : › Normal and abnormal levels of plasma proteins and diseases associated with increased and decreased levels. › Immunochemistry › Components of the immune system.

Diseases associated with disorders in the immune system, multiple myeloma, systemic lupus erythromatosis, heavy- chain diseases, macroglobulinemia etc.  Clinical Enzymology › Changes in enzymatic activity in disease states  Hemoglobin › Normal and types of abnormal hemoglobins. › Pathological cases associated with abnormal hemoglobin, e.g., thalassemia, sickle cell anemia etc.

 Disorders of Lipid Metabolism › Hyper and hypolipoproteinemia. › Atherosclerosis & lipidoses. › Fatty liver  Disorders of Electrolytes, Blood Gases &Acid- base Balance › Sodium, potassium, chloride & their diagnostic value. › Gas transport in the blood (Oxygen & CO2). › Blood pH and its regulation. › Acidosis and alkalosis (Metabolic and respiratory) & Pathological conditions associated with each condition.

 Blood analysis: › Electrophoretic separation of plasma proteins. › Electrophoretic separation of plasma lipoproteins.  Estimation of serum enzymes: › LDH and its isoenzymes. › CPK and its isoenzymes.  Ornithine carbamoyl transferase. › 5-nucleotidase. › Isocitric dehydrogenase. › Sorbitol dehydrogenase. › Glucose-6-P dehydrogenase.  Aldolase › Leucine aminopeptidase. › Aspartate and Alanine Aminotransferases AST and ALT.

 Serum electrolytes: › Chloride sodium, Potassium, Calcium, Magnesium, Phosphorus.  Urine Analysis: › Porphyrins. › Urobilinogen, Amino Levulinic Acid (ALA)

 Clinical Biochemistry, 2 nd Edition, 2008, R. Luxton.  Clinical Biochemistry made ridiculously simple, 2010, Stephen Goldberg.  Clinical Biochemistry; An illustrated color text, 2008, Allan Gaw, Michael J. Murphy, Robert A.

 Group 1: Disorders that give rise to Intoxication  Group 2: Disorders involving energy metabolism.  Group 3: Disorders involving complex molecules. (Proposed by JM Saudubray-2002)

This group includes IEM that lead to acute or progressive intoxication from accumulation of toxic compounds proximal to metabolic block.

Includes (Cont):  Congenital Urea Cycle Defects › Arginosuccinate Lyase Def › Ornithine Carbamyl Transferase Def  Sugar Intolerance › Galactosaemia › Hereditary Fructose Intolerance

Includes:  Aminoacidopathies e.g: › Phenylketoneuria (PKU) › Maple Syrup Urine Disease (MSUD) › Tyrosinaemia type I  Organic acidaemias e.g. › Methylmalonic acidaemia (MMA) › Propionic Acidaemia › Isovaleric Acidaemia

This group consists of IEM with symptoms due at least partly to a deficiency of energy production or utilization. They result from a defect in the: › Liver › Myocardium › Brain › Muscle

Includes:  Hypoglycaemic disorders › Gluconeogenesis defects › Glycogenosis defects › Hyperinsulinism  Fatty Acid Oxidation Disorders

Includes (Cont)  Congenital Lactic Acidaemias › Pyruvate carboxylase deficiency › Krebs Citric Cycle defects › Mitochondrial Respiratory Chain defects

This group includes diseases that involve defects in the synthesis or the catabolism of complex molecules. These diseases are:  Progressive  Permanent  Independent of intercurrent events  Not amenable to treatment.

Includes:  Lysosomal Disorders  Peroxisomal Disorders  Golgi Apparatus Disorders  Inborn Errors of Cholesterol Synthesis

 Carbohydrate metabolism › Glycogen storage diseases various › Galactosemia galactose-1-phosphate uridyle transferase, galactose kinase › Hereditary fructose intolerance fructose bisphosphate aldolase  Amino acid metabolism › Phenylketonuria phenylalanine hydroxylase › Alkaptonuria homogentisic acid oxidase › Maple syrup urine disease branched chain ketoacid hydroxylase

 Lipid metabolism › Hyper and hypo lipoproteinemiavarious  Steroid metabolism › Congenital adrenal hyperplasia21-hydroxylase  Purine metabolism › Gout various › Lesch-Nyhan syndromeHGPRT (hypoxanthine-guanine phosphoribosyl transferase)

 Lysosomal storage disease › Tay-sachs disease……..hexosaminidase A › Gaucher’s disease……..glycosylceramidase  Cell transport defects › Cystinuria……….amino acid transport › Renal glycosuria……….glucose transport › Renal tubular acidosis….hydrogen ion transport

 About 5 million children die in the first month of life in developing countries  Four million children are born with some congenital anomaly. WHO

 Almost % of babies dying of SIDS are now proved to be having some Inborn Errors of Metabolism (IEM).  About 5 to 15 % of all sick neonates in NICU are expected to have some IEM WHO

 a single gene defect causes a clinically significant block in a metabolic pathway resulting either in accumulation of substrate behind the block or deficiency of the product

 IEM arises from a damaged gene which leads to abnormal enzyme.  May be autosomal or sex-linked.  May be recessive or dominant in expression.  Heterozygote will have both normal and abnormal alleles. But homozygote will have two alleles the same on each chromosome.

 An accumulation of the substrate before the enzyme defect*.  A decrease in the amount of the product is observed.  An increased concentration of the alternative metabolites*.  A decrease or absence of the enzyme activity.

 Screening for IEM who do not have the symptoms  Investigations of the patient with symptoms of the IEM

May be carried out in three stages: a. Diagnosis of Broad Category: Saudubray et al (2002)* suggested a battery of simple and routine tests for identification of the broad category of the disorders. These tests include plasma electrolytes, ABGs, blood ammonia and lactic acid etc. * Saudubray JM, Nasoogne MC, Lonlay PD, Touati G. Clinical approach to inherited metabolic disorders in neonates: an overview. Smin Neonatol 2002; 7: 3-15.

May be carried out in three stages: b. Diagnosis of the exact disorder It requires very sophisticated equipment e.g. HPLC, tandem mass spectrometry, GC-MS and ion exchange chromatography.

May be carried out in three stages: b. Diagnosis of the exact disorder (cont) These techniques also require elaborate infrastructure of trained manpower, proper back-up service for the instruments and regular supply of reagents.

May be carried out in three stages: b. Diagnosis of the exact disorder (cont) AKU hospital has taken an initiative to establish the first-ever lab in the country for the pin-point diagnosis of some of the IEM.

May be carried out in three stages: c. Determination of deficient enzyme or protein Although a few laboratories in the world provide this facility, this is only of academic and research interest. Diagnosis of the genetic defect provides another promising pathway for some of these disorders.