Disorders of amino acid and peptide metabolism

Disorders of Amino Acid and Peptide Metabolism

Overview:
Disorders of amino acid and peptide metabolism are inherited or acquired conditions caused by abnormalities in the breakdown, synthesis, transport, or utilization of amino acids and peptides. These defects can lead to accumulation of toxic metabolites, deficiency of essential products, and impairment of neurological, hepatic, renal, or developmental functions.

Common Disorders Include:

• Phenylketonuria (PKU)
• Maple Syrup Urine Disease (MSUD)
• Homocystinuria
• Tyrosinemia
• Alkaptonuria
• Cystinuria
• Urea Cycle Disorders
• Non-ketotic Hyperglycinemia
• Glutaric Aciduria
• Methylmalonic Acidemia
• Propionic Acidemia
• Disorders of branched-chain amino acid metabolism
• Disorders of amino acid transport and reabsorption
• Peptide metabolism and transport disorders

Clinical Indications:

• Unexplained developmental delay or intellectual disability
• Seizures or neurological abnormalities
• Recurrent vomiting or metabolic crises
• Failure to thrive or poor growth
• Unusual body or urine odor
• Unexplained metabolic acidosis or hyperammonemia
• Liver dysfunction
• Family history of inherited metabolic disease
• Suspected inborn errors of metabolism

Testing Approach:
Depending on the suspected disorder, evaluation may include plasma amino acids, urine organic acids, acylcarnitine profile, ammonia, metabolic screening, enzyme assays, and molecular genetic testing.

Why Genetic Testing Matters:
Molecular testing can help identify the underlying genetic cause, confirm a suspected diagnosis, guide management, support family screening, and assist with reproductive counseling.

Sample: Varies according to the test/panel; commonly blood or urine.
Method: Biochemical analysis and/or molecular genetic testing, depending on the specific investigation.
Turnaround Time: Varies according to the test and methodology.