Molecular genetic study of glutaric aciduria, type I: Identification of a novel mutation

Two novel compound heterozygous variants of the GCDH gene in two Chinese families with glutaric acidaemia type I identified by high-throughput sequencing and a literature review

Autosomal recessive glutaric acidaemia type I (GA-I) is a rare hereditary metabolic disease characterized by increased organic acids and neurologic symptoms. Although numerous variants in the GCDH gene have been identified to be connected with the pathogenesis of GA-I, the relationship between genotype and phenotype remains uncertain. In this study, we evaluated genetic data for two GA-I patients from Hubei, China, and we reviewed the previous research findings to clarify the genetic heterogeneity of GA-I and identify the potential causative variants. After we extracted genomic DNA from peripheral blood samples obtained from two unrelated Chinese families, we used target capture high-throughput sequencing combined with Sanger sequencing to determine likely pathogenic variants in the two probands. Electronic databases were also searched for the literature review. The genetic analysis revealed two compound heterozygous variants in the GCDH gene expected to lead to GA-I in the two probands (P1 and P2), with P1 carrying two known variants (c.892G > A/p. A298T and c.1244-2A > C/IVS10-2A > C) and P2 harbouring two novel variants (c.370G > T/p.G124W and c.473A > G/p.E158G). In the literature review, the most common alleles in low excretors (i.e., individuals with low excretion of GA) were R227P, V400M, M405V, and A298T, with variation in the severity of clinical phenotypes. Overall, we identified two novel GCDH gene candidate pathogenic variants in a Chinese patient, enriching the GCDH gene mutational spectrum and providing a solid foundation for the early diagnosis of GA-I patients with low excretion.

A novel mutation in the glutaryl-CoA dehydrogenase gene (GCDH) in an Iranian patient affected with Glutaric acidemia type 1

Our findings revealed the mutation c.536T>C (p. Leu179Pro) in GCDH gene although has not been reported so far, but the in-silico analysis and clinical symptoms of the patient indicated that the mutation is pathogenic full stop. Also, it can be diagnosed and prevented in families affected by the disease.

Rhabdomyolysis, Acute Kidney Injury, and a Novel Frameshift Mutation in a Child with Glutaric Acidemia Type I

This is a case report of a girl with glutaric acidemia type I (GA-I) who experienced rhabdomyolysis and acute kidney injury (AKI). Her first acute metabolic crisis occurred at the age of 5 months, which mainly manifested as irritable crying, poor appetite, and hyperlactatemia. Mutation analysis showed 2 pathogenic mutations in the glutaryl-CoA dehydrogenase (GCDH) gene, which were c.383G>A (p.R128Q) and c.873delC (p.N291Kfs*41), the latter of which is a novel frameshift mutation of GA-I. She had a febrile illness at the age of 12 months, followed by AKI and severe rhabdomyolysis. Four days of continuous venovenous hemodiafiltration (CVVHDF) helped to overcome this acute decompensation. This case report describes a novel mutation in the GCDH gene, that is, c.873delC (p.N291Kfs*41). Also, it highlights the fact that patients with GA-I have a high risk of rhabdomyolysis and AKI, which may be induced by febrile diseases and hyperosmotic dehydration; CVVHDF can help to overcome this acute decompensation.

Functions and Mechanisms of Lysine Glutarylation in Eukaryotes

Lysine glutarylation (Kglu) is a newly discovered post-translational modification (PTM), which is considered to be reversible, dynamic, and conserved in prokaryotes and eukaryotes. Recent developments in the identification of Kglu by mass spectrometry have shown that Kglu is mainly involved in the regulation of metabolism, oxidative damage, chromatin dynamics and is associated with various diseases. In this review, we firstly summarize the development history of glutarylation, the biochemical processes of glutarylation and deglutarylation. Then we focus on the pathophysiological functions such as glutaric acidemia 1, asthenospermia, etc. Finally, the current computational tools for predicting glutarylation sites are discussed. These emerging findings point to new functions for lysine glutarylation and related enzymes, and also highlight the mechanisms by which glutarylation regulates diverse cellular processes.