OBJECTIVE: To analyze the clinical and genetic characteristics of three Chinese pedigrees affected with Citrullinemia type I (CTLN1). METHODS: Three children diagnosed at the Children's Hospital Affiliated to Shandong University from 2017 to 2020 were selected as the study subjects. Genomic DNA was extracted from peripheral blood samples of the probands and their parents. Next generation sequencing (NGS) was carried out to detect pathological variants of the probands. Sanger sequencing was used for validating the candidate variant among the pedigrees. RESULTS: The probands have respectively carried compound heterozygous variants of c.207_209delGGA and c.1168G>A, c.349G>A and c.364-1G>A, c.470G>A and c.970G>A of the ASS1 gene, which were respectively inherited from their parents. CONCLUSION The newly discovered c.207_209delGGA and c.364-1G>A variants have enriched the mutational spectrum of the ASS1 gene. And the mutation spectrum of Chinese CTLN1 patients is heterogeneous.
Child ; Humans ; Argininosuccinate Synthase/genetics* ; Citrullinemia/genetics* ; East Asian People ; Mutation ; Pedigree

OBJECTIVETo detect potential mutations in six patients with citrullinemia.

METHODSGenomic DNA was extracted from peripheral blood samples from the patients. Mutations of the ASS1, ASL and SLC25A13 genes were screened using microarray genotyping combined with direct sequencing.

RESULTSOne patient was diagnosed with argininosuccinate lyase deficiency, and has carried a homozygous c.1311T>G (p.Y437*) mutation of the ASL gene. The remaining five patients were diagnosed with neonatal intrahepatic cholestasis due to citrin deficiency, and have respectively carried mutations of the SLC25A13 gene including [c.851-854delGTAT+c.851-854delGTAT], [c.851-854delGTAT+IVS6+5G>A], [c.851-854delGTAT+IVS16ins3kb], [c.851-854delGTAT+IVS6-11A>G] and [c.851-854delGTAT+c.1638-1660dup23]. Among these, the c.1311T>G mutation was first identified in the Chinese population, and the IVS6-11A>G mutation was a novel variation which may affect the splicing, as predicted by Human Splicing Finder software.

CONCLUSIONThis study has confirmed the molecular diagnosis of citrullinemia in six patients and expanded the mutational spectrum underlying citrullinemia.

Argininosuccinate Lyase ; genetics ; Argininosuccinate Synthase ; genetics ; Citrullinemia ; genetics ; DNA Mutational Analysis ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Mitochondrial Membrane Transport Proteins ; genetics ; Mutation

OBJECTIVETo identify the genetic mutation in ASS1 gene in a Chinese family with citrullinemia typeI, which may provide a basis for the diagnosis and genetic counseling.

METHODGenomic DNA was isolated from peripheral blood samples of the family members. Mutation analysis of ASS1 gene was carried out by PCR and Sanger sequencing. Biostructural analysis of the mutated ASS1 was completed by Phyre server.

RESULTDouble heterozygous mutations in the proband were identified: c.951delT (F317LfsX375) and c.1087C>T (R363W), which were confirmed in the proband's father and mother, respectively. It was found that the c.951delT mutation might change the formation of a dimer or a tetramer and the function of ASS1 protein.

CONCLUSIONDouble heterozygous mutations for c.951delT and c.1087C>T have been found in a proband with citrullinemia typeI. The c.951delT is a novel mutation in citrullinemia typeI, which may change the configuration of ASS1 protein and result in ASS1 dysfunction.

Argininosuccinate Synthase ; genetics ; Asian Continental Ancestry Group ; genetics ; Citrullinemia ; genetics ; DNA Mutational Analysis ; Humans ; Infant, Newborn ; Mutation

OBJECTIVETo detect potential mutations of Y9ASS1, ASL and SLC25A13 genes in four patients manifesting citrullinemia.

METHODSGenomic DNA was extracted from peripheral blood leukocytes. Exons and their flanking sequences of the three genes were amplified with polymerase chain reaction and subjected to direct DNA sequencing.

RESULTSBased on DNA sequence analysis, one case was diagnosed with argininosuccinate synthetase deficiency, and the mutation type (ASS1 gene) was c.236C>T (p.S79F) + c.431C>G (p.P144R). Two cases were diagnosed with argininosuccinic aciduria (ASL gene), and their gene mutations were c.434A>G (p.D145G) + c.1366C>T (p.R456W) and c.331C>T (p.R111W) + IVS8+2insT, respectively. A thirteen months boy who carried a heterozygous 851del4 mutation (SLC25A13 gene) was diagnosed with citrullinemia adult-onset type II.

CONCLUSIONThrough analysis of relevant pathogenic genes, four patients have been diagnosed.

Adult ; Amino Acid Sequence ; Argininosuccinate Lyase ; genetics ; metabolism ; Argininosuccinate Synthase ; genetics ; metabolism ; Base Sequence ; Citrullinemia ; enzymology ; genetics ; Female ; Humans ; Infant ; Male ; Mitochondrial Membrane Transport Proteins ; genetics ; metabolism ; Molecular Sequence Data ; Pedigree ; Point Mutation

OBJECTIVETo investigate potential mutation of the ASS1 gene in a male infant with acute citrullinemia type I.

METHODSGenomic DNA was prepared from peripheral blood samples of the family members. Mutation analysis of the 14 ASS1 exons was carried out by PCR and direct DNA sequencing.

RESULTSA homozygous missense mutation of c.970G>A located in exon 13, which results in p.G324S, was identified in the child. Sequencing of the parents showed a heterozygous status for the same mutation.

CONCLUSIONA missense mutation of c.970G>A in the ASS1 gene is responsible for the pathogenesis of the disease in the infant.

Amino Acid Sequence ; Amino Acid Substitution ; Argininosuccinate Synthase ; chemistry ; genetics ; Base Sequence ; Citrullinemia ; genetics ; Gene Order ; Humans ; Infant ; Male ; Models, Molecular ; Molecular Sequence Data ; Mutation, Missense ; Protein Conformation ; Sequence Alignment ; Sequence Analysis, DNA