Structural and Functional Impact of Seven Missense Variants of Phenylalanine Hydroxylase

PECIMONOVA, Martina, Daniela KLUCKOVA, František CSICSAY, Kamila RÉBLOVÁ, Jan KRAHULEC, Dagmar PROCHÁZKOVÁ, Ludovit ŠKULTETY, Ludevít KADASI and Andrea ŠOLTYSOVÁ. Structural and Functional Impact of Seven Missense Variants of Phenylalanine Hydroxylase. Genes. Basilej: MDPI, 2019, vol. 10, No 6, p. 1-13. ISSN 2073-4425. Available from: https://dx.doi.org/10.3390/genes10060459.

Basic information

• Original name: Structural and Functional Impact of Seven Missense Variants of Phenylalanine Hydroxylase
• Name in Czech: Strukturální a funkční vliv sedmi missense patogennich sekvencnich variant na enzym fenylalanin hydroxylazu
• Authors: PECIMONOVA, Martina (703 Slovakia), Daniela KLUCKOVA (703 Slovakia), František CSICSAY (703 Slovakia), Kamila RÉBLOVÁ (203 Czech Republic, belonging to the institution), Jan KRAHULEC (703 Slovakia), Dagmar PROCHÁZKOVÁ (203 Czech Republic, belonging to the institution), Ludovit ŠKULTETY (703 Slovakia), Ludevít KADASI (703 Slovakia) and Andrea ŠOLTYSOVÁ (703 Slovakia, guarantor).
• Edition: Genes, Basilej, MDPI, 2019, 2073-4425.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: 10603 Genetics and heredity
• Country of publisher: Switzerland
• Confidentiality degree: is not subject to a state or trade secret
• WWW: URL
• Impact factor: Impact factor: 3.759
• RIV identification code: RIV/00216224:14110/19:00109997
• Organization unit: Faculty of Medicine
• Doi: http://dx.doi.org/10.3390/genes10060459
• UT WoS: 000473797000054
• Keywords (in Czech): fenylalnin hydroxylaza fenylketonurie BH4 funkční studie missense varianty
• Keywords in English: Phenylalanine hydroxylase phenylketonuria BH4 functional studies missense variants
• Tags: 14110317, podil, rivok
• Tags: International impact, Reviewed

Abstract

The molecular genetics of well-characterized inherited diseases, such as phenylketonuria (PKU) and hyperphenylalaninemia (HPA) predominantly caused by mutations in the phenylalanine hydroxylase (PAH) gene, is often complicated by the identification of many novel variants, often with no obvious impact on the associated disorder. To date, more than 1100 PAH variants have been identified of which a substantial portion have unknown clinical significance. In this work, we study the functionality of seven yet uncharacterized PAH missense variants p.Asn167Tyr, p.Thr200Asn, p.Asp229Gly, p.Gly239Ala, p.Phe263Ser, p.Ala342Pro, and p.Ile406Met first identified in the Czech PKU/HPA patients. From all tested variants, three of them, namely p.Asn167Tyr, p.Thr200Asn, and p.Ile406Met, exerted residual enzymatic activity in vitro similar to wild type (WT) PAH, however, when expressed in HepG2 cells, their protein level reached a maximum of 72.1% ± 4.9%, 11.2% ± 4.2%, and 36.6% ± 7.3% compared to WT PAH, respectively. Remaining variants were null with no enzyme activity and decreased protein levels in HepG2 cells. The chaperone-like effect of applied BH4 precursor increased protein level significantly for p.Asn167Tyr, p.Asp229Gly, p.Ala342Pro, and p.Ile406Met. Taken together, our results of functional characterization in combination with in silico prediction suggest that while p.Asn167Tyr, p.Thr200Asn, and p.Ile406Met PAH variants have a mild impact on the protein, p.Asp229Gly, p.Gly239Ala, p.Phe263Ser, and p.Ala342Pro severely affect protein structure and function.