Evidence map›Paper›PMID 41618427›Full record

ArticleOrphanet journal of rare diseases2026

Impact of glycerol phenylbutyrate on biochemistry and outcomes in paediatric patients with urea cycle disorders: a multicentre case series from Saudi Arabia.

Rawan Hejazi, Thamer H Alghamdi, Rihab Salih, Yousra Naeim, Hamad Althiyab, Talal AlAnzi, Sarar Mohamed, Majid Alfadhel, Ruqaiah Saleh ALTassan, Zuhair N Al-Hassnan and 1 more

Abstract readMulticenter Study
In one paragraph

Article in Orphanet journal of rare diseases, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

11 authors.

Rawan HejaziAlfaisal University, Riyadh, Saudi Arabia.
Thamer H AlghamdiKing Abdulaziz Medical City, King Abdullah Specialized Children Hospital, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.
Rihab SalihPrince Sultan Military Medical City, Riyadh, Saudi Arabia.
Yousra NaeimPrince Sultan Military Medical City, Riyadh, Saudi Arabia.
Hamad AlthiyabKing Abdulaziz Medical City, King Abdullah Specialized Children Hospital, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.
Talal AlAnziJohns Hopkins Aramco Healthcare Centre, Dhahran, Saudi Arabia.
Sarar MohamedAlfaisal University, Riyadh, Saudi Arabia.
Majid AlfadhelKing Abdulaziz Medical City, King Abdullah Specialized Children Hospital, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia.
Ruqaiah Saleh ALTassanAlfaisal University, Riyadh, Saudi Arabia.
Zuhair N Al-HassnanAlfaisal University, Riyadh, Saudi Arabia.
Moeenaldeen AlSayedAlfaisal University, Riyadh, Saudi Arabia. moeen@kfshrc.edu.sa.ORCID http://orcid.org/0000-0003-1995-8465

Funding

Immedica Pharma AB Immedica Pharma AB
6 · The paper itself

Abstract

backgroundUrea cycle disorders (UCDs) are rare inherited conditions that disrupt ammonia detoxification, leading to hyperammonaemia and potential neurological harm. In Saudi Arabia, high consanguinity rates increase UCD birth incidence. Traditional nitrogen scavengers - sodium benzoate (NaBz) and sodium phenylbutyrate (NaPBA) - are limited by poor palatability, high sodium burden, and large dosing volumes. Glycerol phenylbutyrate (GPB) offers improved pharmacological and practical properties, including slow intestinal hydrolysis, reduced dosing frequency, absence of sodium and propylene glycol, and better tolerability. This study assessed real-world outcomes of GPB in a paediatric UCD population.

methodsWe conducted a retrospective analysis of 37 paediatric patients from three Saudi hospitals. Pre- and post-GPB data were compared for plasma ammonia, hyperammonaemic crises (HACs), HAC-related hospitalisations and durations, growth z-scores, and adverse events. A caregiver survey (n = 15) captured treatment experiences and preferences.

resultsGPB significantly reduced routine plasma ammonia levels by 21% (median 72 to 57 µmol/L, p = 0.011), with the proportion of patients above the local reference range dropping from 74% to 42%. Annualised HAC rates fell by 55% (2.2 to 1.0/year), HAC-related hospitalisations by 27% (1.1 to 0.8/year), and annualised HAC-related hospital stays by 24% (3.3 to 2.5 days/year), though these did not reach statistical significance. Growth z-scores showed small, non-significant upward trends (+ 0.2 for height and weight). GPB was well tolerated, with no treatment-related adverse events. All survey respondents (15/15) preferred GPB over NaBz and NaPBA. 100% rated GPB equal or superior in controlling ammonia levels and being easier to adhere to, and 85% found it equal or better for palatability.

conclusionsGPB improved biochemical control and showed consistent trends toward reduced clinical burden in a real-world paediatric UCD cohort. Although some outcomes were not statistically significant, likely due to sample size and inter-individual variability, the magnitude and direction of change - supported by unanimous patient preference - highlight GPB’s advantages. These findings support its use as a first-line or step-up therapy in paediatric UCDs.

Indexed as

GlycerolPhenylbutyratesUrea Cycle Disorders, InbornAdolescentAmmoniaChildChild, PreschoolFemaleHumansInfantMaleRetrospective StudiesSaudi ArabiaSodium BenzoateAmmoniaGlycerolglycerol phenylbutyratePhenylbutyratesSodium BenzoateBiochemical outcomesGlycerol phenylbutyratePaediatric metabolic diseasesSaudi Arabia healthcareUrea cycle disorders

Identifiers

PMID41618427
PMCPMC12934098

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.