Premium
The 1‐ 13 C galactose breath test in GALT deficient patients distinguishes NBS detected variant patients but does not predict outcome in classical phenotypes
Author(s) -
WelsinkKarssies Mendy M.,
Harskamp Dewi,
Ferdinandusse Sacha,
Hollak Carla E. M.,
Huidekoper Hidde H.,
Janssen Mirian C. H.,
Kemper E. Marleen,
Langendonk Janneke G.,
RubioGozalbo M. Estela,
Vries Maaike C.,
Wijburg Frits A.,
Schierbeek Henk,
Bosch Annet M.
Publication year - 2020
Publication title -
journal of inherited metabolic disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 102
eISSN - 1573-2665
pISSN - 0141-8955
DOI - 10.1002/jimd.12207
Subject(s) - galactosemia , galactose , gastroenterology , medicine , phenotype , compound heterozygosity , newborn screening , clinical phenotype , endocrinology , pediatrics , biology , biochemistry , gene
Classical galactosemia (CG) patients frequently develop long‐term complications despite early dietary treatment. The highly variable clinical outcome is poorly understood and a lack of prognostic biomarkers hampers individual prognostication and treatment. The aim of this study was to investigate the association between residual galactose oxidation capacity and clinical and biochemical outcomes in CG patients with varying geno‐ and phenotypes. The noninvasive 1‐ 13 C galactose breath test was used to assess whole body galactose oxidation capacity. Participants received a 7 mg/kg oral dose of 1‐ 13 C labelled galactose. The galactose oxidation capacity was determined by calculating the cumulative percentage dose of the administered galactose (CUMPCD) recovered as 13 CO 2 in exhaled air. Forty‐one CG patients (5–47 years) and four adult controls were included. The median galactose oxidation capacity after 120 minutes (CUMPCDT120) of 34 classical patients (0.29; 0.08–7.51) was significantly lower when compared to two homozygous p.Ser135Leu patients (9.44; 8.66–10.22), one heterozygous p.Ser135Leu patient 18.59, four NBS detected variant patients (13.79; 12.73–14.87) and four controls (9.29; 8.94–10.02). There was a clear correlation between Gal‐1‐P levels and CUMPCDT120 ( P < .0005). In the classical patients, the differences in CUMPCDT120 were small and did not distinguish between patients with poor and normal clinical outcomes. The galactose breath test distinguished classical patients from homo‐ and heterozygous p.Ser135Leu and NBS detected variant patients, but was not able to predict clinical outcomes in classical patients. Future studies are warranted to enable individualised prognostication and treatment, especially in NBS variants with galactose oxidation capacities in the control range.