Tetrahydrobiopterin-responsive phenylketonuria: the Czech experience
| Title in English | Tetrahydrobiopterin - responsive phenylketonuria: The Czech experience |
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| Authors | |
| Year of publication | 2011 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Phenylketonuria (OMIM 261600) is an inherited metabolic disease due to a deficiecy of hepatic phenylalaninhydroxylase (PAH;12q24.1). Tetrahydrobiopterin (BH4) responsiveness in patients with specific mutations in the PAH gene is a subtype of hyperfenylalaninaemia (HPA) charecterised by a positive BH4 loading test. Methods: We tested 23 patients with HPA/PKU, 4–39 years of age, selected (based on genotype) as a potentially BH4 responsive and loaded with BH4 (20 mg/kg). Results: Overall 10/23 showed positive response of more than 30% decrease in blood Phe levels 8 h after BH4 challenge, and 7/23 showed this decrease after 24 h. The majority of the responsive patients belong to mild HPA (13/17). In p.E390G, p.A300S, p. A403V, p. Y414C, p.I306V, p. G272X and p.Y387H mutations were 100% associated with BH4 responsiveness. The p.R158Q mutation was inconstantly responsive. The EX5del-4 kb mutation was responsive regardless of the second allele (p.A403V, p.R408W). In patient with mild PKU and novel mutation p. K396R (genotype p.R408W/p.K396R) no responsiveness was noticed. Conclusion: The best responders were patients with mild HPA. Very interesting group are patients with the novel mutation in the PAH gene. |