Aminoaciduria in handicapped children: a study using ion-exchange chromatography as a screening test

Area of Science:

• Biochemistry
• Pediatrics
• Medical Genetics

Background:

• Aminoaciduria, the excretion of amino acids in urine, can indicate underlying metabolic disorders.
• Establishing normal reference ranges for amino acid excretion is crucial for diagnosing these conditions in children.

Purpose of the Study:

• To measure and analyze amino acid excretion levels in a cohort of normal and handicapped children.
• To identify individuals excreting amino acids above established normal percentiles.

Main Methods:

• Ion-exchange chromatography was employed to quantify amino acid excretion.
• Computer-assisted statistical analysis was used to determine normal frequency distributions.
• Abnormal excretion was defined as levels exceeding the 99.75th or 100th percentiles.

Main Results:

• Out of 75 handicapped children, 18 exhibited abnormal amino acid excretion.
• Identified conditions included dibasic aminoaciduria, phenylketonuria, hyperphenylalaninuria, cystathioninuria, hyperglycinuria, and hypertaurinuria.
• Specific cases involved combined hyperglycinuria and hypertaurinuria, and one child showed elevated levels of multiple amino acids (taurine, serine, tyrosine, histidine).

Conclusions:

• Abnormal amino acid excretion is present in a subset of physically and/or mentally handicapped children.
• The study successfully identified specific aminoacidurias, underscoring the utility of chromatographic analysis in diagnosing metabolic disorders.
• Further investigation into the identified cases is warranted to understand the clinical implications of these aminoacidurias.