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Efficient Purification and LC-MS/MS-based Assay Development for Ten-Eleven Translocation-2 5-Methylcytosine Dioxygenase
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Differential diagnosis of tetrahydrobiopterin deficiency

A Niederwieser, A Ponzone, H C Curtius

    Journal of Inherited Metabolic Disease
    |January 1, 1985
    PubMed

    Insights

    This study screened 673 children for tetrahydrobiopterin (BH4) deficiency, identifying 51 cases. BH4 loading tests helped diagnose BH4 biosynthesis defects but not all dihydropteridine reductase deficiencies, suggesting further diagnostic methods are needed.

    Area of Science:

    • Biochemistry
    • Genetics
    • Pediatrics

    Background:

    • Tetrahydrobiopterin (BH4) deficiency is a rare genetic disorder affecting neurotransmitter synthesis.
    • Early diagnosis and treatment are crucial to prevent severe neurological complications.

    Purpose of the Study:

    • To screen a pediatric population for BH4 deficiency.
    • To evaluate diagnostic methods for different types of BH4 deficiency.
    • To assess treatment response to BH4 loading tests.

    Main Methods:

    • High-performance liquid chromatography (HPLC) of urine pterins.
    • Tetrahydrobiopterin (BH4) load test.
    • Measurement of dihydropteridine reductase (DHPR) activity in blood spots.
    • Analysis of cerebrospinal fluid (CSF) metabolites.

    Main Results:

    • 51 children diagnosed with BH4 deficiency: 1 GTP cyclohydrolase I deficiency, 36 dihydrobiopterin synthetase (DHBS) deficiency, and 14 dihydropteridine reductase deficiency (DHPR).
    • BH4 loading effectively lowered serum phenylalanine in 37 patients with BH4 biosynthesis defects.
    • Four of 14 DHPR deficiency patients did not respond to BH4 loading, indicating diagnostic challenges.
    • Reduced phosphate-eliminating enzyme activity found in a DHBS deficiency patient's liver biopsy.

    Conclusions:

    • Screening for BH4 deficiency using HPLC and BH4 load tests is effective.
    • Measurement of DHPR activity in blood spots is recommended for diagnosing DHPR deficiency.
    • CSF metabolite analysis is vital for diagnosing BH4 deficiency subtypes and monitoring therapy.
    • BH4 deficiency diagnosis and management require comprehensive biochemical and clinical evaluation.

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