Phenylalanine hydroxylase deficiency treatment and management: A systematic evidence review of the American College of Medical Genetics and Genomics (ACMG).

Abstract

PURPOSE:

Elevated serum phenylalanine (Phe) levels due to biallelic pathogenic variants in phenylalanine hydroxylase (PAH) may cause neurodevelopmental disorders or birth defects from maternal phenylketonuria. New Phe reduction treatments have been approved in the last decade, but uncertainty on the optimal lifespan goal Phe levels for patients with PAH deficiency remains.

METHODS:

We searched Medline and Embase for evidence of treatment concerning PAH deficiency up to September 28, 2021. Risk of bias was evaluated based on study design. Random-effects meta-analyses were performed to compare IQ, gestational outcomes, and offspring outcomes based on Phe ≤ 360 μmol/L vs > 360 μmol/L and reported as odds ratio and 95% CI. Remaining results were narratively synthesized.

RESULTS:

A total of 350 studies were included. Risk of bias was moderate. Lower Phe was consistently associated with better outcomes. Achieving Phe ≤ 360 μmol/L before conception substantially lowered the risk of negative effect to offspring in pregnant individuals (odds ratio = 0.07, 95% CI = 0.04-0.14; P < .0001). Adverse events due to pharmacologic treatment were common, but medication reduced Phe levels, enabling dietary liberalization.

CONCLUSIONS:

Reduction of Phe levels to ≤360 μmol/L through diet or medication represents effective interventions to treat PAH deficiency.

• Authors: April D Adams, Moisés Ó Fiesco-Roa, Lawrence Wong, Gabrielle P Jenkins, Jennifer Malinowski, Olivia M Demarest, Paul G Rothberg, Judith A Hobert, ACMG Therapeutics Committee. Electronic address: [email protected]
• Journal: Genetics in medicine : official journal of the American College of Medical Genetics (Genet Med) Vol. 25 Issue 9 Pg. 100358 (09 2023) ISSN: 1530-0366 [Electronic] United States
• PMID: 37470789 (Publication Type: Systematic Review, Practice Guideline, Journal Article)
• Copyright: Copyright © 2022 American College of Medical Genetics and Genomics. Published by Elsevier Inc. All rights reserved.

Chemical References

• Phenylalanine
• Phenylalanine Hydroxylase

Topics

• Pregnancy
• Female
• Humans
• United States
• Genetics, Medical
• Phenylalanine
• Phenylketonurias (drug therapy, genetics)
• Phenylalanine Hydroxylase (genetics)
• Phenylketonuria, Maternal
• Genomics