OBJECTIVE: To explore the incidence, clinical features, genetic variant characteristics and prognosis of Glutaric acidemia type I (GA1) among neonates from Henan Province. METHODS: A total of 814 625 neonates undergoing screening for inherited metabolic diseases by tandem mass spectrometry (MS/MS) at the Third Affiliated Hospital of Zhengzhou University from January 2016 to December 2022 were selected as the study subjects. A retrospective method was adopted to collect the clinical data of the patients. Whole exome sequencing was carried out to detect GCDH gene variants in individuals with positive results by GA1 newborn screening, and Sanger sequencing was used to verify the candidate variants. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the pathogenicity of candidate variants was rated. This study was approved by the Medical Ethics Committee of the Hospital (Ethics Number: 2019 Medical Ethics Review No. 67). RESULTS: Eight cases of GA1 were diagnosed among the 814 625 neonates. Blood glutaryl carnitine (C5DC) and urine glutaric acid (GA) levels of the 8 children were higher than the normal reference values. In total 12 variants were detected, all of which were missense variants. c.1064G>A (p.Arg355His) was the most common one, accounting for 21.4% (3/14). Three GCDH gene variants, including 1297G>C (p.Ala433Pro), c.467G>A (p.Gly156Asp) and c.1125T>G (p.Cys375Trp), were previously unreported. REVEL software analysis predicted that all of the three variants were harmful. 3D protein structure modeling indicated that the three variants may cause amino acid residue alterations, and c.1297G>C (p.Ala433Pro) and c.1125T>G (p.Cys375Trp) may result in increase in hydrogen bonds and affect the function of GCDH protein. By December 2023, one of the eight children had deceased, and another child had severe clinical symptoms with poor prognosis. Six children had a good prognosis, of which two had mild motor development delay and four had normal development without clinical symptoms. CONCLUSION The incidence of GA1 in newborns screened by MS/MS in Henan Province is 1/101 828, and the carrier rate of pathogenic GCDH variants is 1/160. The c.1064G>A (p.Arg355His) may be the hotspot variant of the GCDH gene among children with GA1 in Henan. Discovery of the three novel variants has enriched the mutational spectrum of the GCDH gene and provide a basis for the early diagnosis, treatment, prognosis and genetic counseling of this disease.
Humans ; Amino Acid Metabolism, Inborn Errors/epidemiology* ; Glutaryl-CoA Dehydrogenase/chemistry* ; Infant, Newborn ; Female ; Neonatal Screening/methods* ; Male ; Brain Diseases, Metabolic/epidemiology* ; China/epidemiology* ; Retrospective Studies ; Mutation ; Genetic Variation ; Glutarates

OBJECTIVETo report on clinical features of four patients with glutaric academia type Ⅰ (GA-1) and mutations identified in the glutaryl-CoA dehydrogenase (GCDH) gene.

METHODSAll of the patients underwent magnetic resonance imaging (MRI) analysis. Blood acylcarnitine and urine organic acid were analyzed with tandem mass spectrometry and gas chromatographic mass spectrometry. Genomic DNA was extracted from peripheral blood samples. The 11 exons and flanking sequences of the GCDH gene were amplified with PCR and subjected to direct DNA sequencing.

RESULTSMutations of the GCDH gene were identified in all of the patients. Three had homozygous mutations. A recurrent mutation, IVS10-2A>C, was found in the four unrelated families, while the mutation of c.245G>C (p.Arg82Pro) was novel.

CONCLUSIONIVS10-2A>C is likely a founder mutation for Chinese population in Wenzhou.

Amino Acid Metabolism, Inborn Errors ; diagnostic imaging ; enzymology ; genetics ; Amino Acid Sequence ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; Brain Diseases, Metabolic ; diagnostic imaging ; enzymology ; genetics ; DNA Mutational Analysis ; Exons ; Female ; Glutaryl-CoA Dehydrogenase ; chemistry ; deficiency ; genetics ; metabolism ; Humans ; Infant ; Magnetic Resonance Imaging ; Male ; Molecular Sequence Data ; Point Mutation ; Radiography ; Sequence Alignment

OBJECTIVETo investigate the mutations of glutaryl-CoA dehydrogenase (GCDH) gene in patients with glutaric aciduria type I(GA-1).

METHODSGenomic DNA was extracted from peripheral blood cells of the eight probands with GA-1 who were diagnosed by urine and blood analyses. By PCR and direct sequencing, all 11 exons and their flanking sequences of the GCDH gene were examined. Mutation search was also performed in some of their family members.

RESULTSAmong the eight patients diagnosed by metabolic screening, seven patients belonged to classical infantile-onset. One patient, however, was adult-onset, who was admitted to the hospital because of suffering from ischemic cerebral stroke. The GCDH gene mutations were identified in all the eight probands with GA-1: five of them had compound heterozygous mutations, while the other three harbored only one heterozygous mutation. Totally, nine different mutations of the GCDH gene were identified in the eight probands, four of them were novel, i.e., c.148T>C, c.371G>A, 909delC and c.263G>A.

CONCLUSIONGCDH gene mutations are identified in 8 patients with GA-1 in mainland China, including one adult patient with late onset. Four novel mutations of GCDH gene are found which expanded the mutational spectrum of the GCDH gene.

Adult ; Amino Acid Metabolism, Inborn Errors ; enzymology ; genetics ; Amino Acid Sequence ; Animals ; Base Sequence ; Brain Diseases, Metabolic ; enzymology ; genetics ; DNA Mutational Analysis ; Exons ; genetics ; Female ; Glutaryl-CoA Dehydrogenase ; chemistry ; deficiency ; genetics ; Humans ; Infant ; Male ; Molecular Sequence Data