Diagnosis of tetrahydrobiopterin deficiency using filter paper blood spots: further development of the method and 5 years experience.

摘要: In every newborn with even mild hyperphenyla- laninemia (HPA) tetrahydrobiopterin (BH4) deficiencies need to be excluded as soon possible. Differential diagnosis is most commonly performed by analysis of urinary neopterin and biopterin. 2005 a new method for the measurement neopterin, biopterin other pterins in dried blood spot (DBS) on filter paper was introduced. order evaluate usefulness this standard tool differential HPAs we analyzed biopterin, pterin dihydropteridine reduc- tase activity DBS from 362 patients HPA over period five years. Age-dependent reference values were established population. Sixty-four BH4 deficiency (27 6- pyruvoyl-tetrahydropterin synthase deficiency, seven GTP cyclohydrolase I 30 dihydrop- teridine reductase) identified. Reference calculated each variants. 6-pyruvoyl-tetrahydropterin can diagnosed alone, while reductase additional deter- mination enzyme same essential. Regarding test sensitivity, interpretation concentration per hemoglobin more valid than liter. Percentage sum should always calculated. addition, determination essential measure efficient extraction Although urine sensitive due higher concentrations present, our data prove their routine deficiencies. Abbreviations