Phenotypic and genetic spectra of galactose mutarotase deficiency: A nationwide survey conducted in Japan.

Purpose: Galactose mutarotase (GALM) deficiency was first reported in 2019 as the fourth type of galactosemia. This study aimed to investigate the clinical and genotypic spectra of GALM deficiency.

Methods: This was a questionnaire-based retrospective survey conducted in Japan between February 2022 and March 2023.

A method for phenylalanine self-monitoring using phenylalanine ammonia-lyase and a pre-existing portable ammonia detection system.

Phenylketonuria is an inborn error of phenylalanine metabolism caused by a phenylalanine hydroxylase deficiency. To prevent the occurrence of neurological symptoms and maternal complications resulting from phenylketonuria, patients must adhere to a strict diet therapy, tetrahydrobiopterin supplementation, or pegvaliase injection to maintain blood phenylalanine levels within a recommended range throughout their lives. Therefore, monitoring blood phenylalanine levels is necessary to determine the recent metabolic status of phenylalanine in patients with PKU; however, there are no available instruments for individuals to monitor their own blood phenylalanine levels using whole fingertip blood.

Usefulness of serum BUN or BUN/creatinine ratio as markers for citrin deficiency in positive cases of newborn screening.

Citrin deficiency belongs to a group of urea cycle disorders that can be identified during newborn screening by measuring citrulline, phenylalanine, methionine, and galactose levels. Early diagnosis of citrin deficiency is beneficial as disease-specific interventions such as permission of food preference and/or supplementation of medium-chain triglyceride can prevent metabolic decompensation. However, there are currently no laboratory tests for the diagnosis of citrin deficiency in routine clinical practice.

Essential oils can cause false-positive results of medium-chain acyl-CoA dehydrogenase deficiency.

Newborn screening is a public health care program worldwide to prevent patients from critical illness or conditions. Tandem mass spectrometry allows multiplex, inexpensive, and rapid newborn screening. However, mass spectrometry used for newborn screening to date is not able to separate peaks of compounds with similar , which could lead to false-positive results without additional second-tier tests, such as fragmentation.