Novel Pathogenic Variant (c.580C>T) in the CPS1 Gene in a Newborn With Carbamoyl Phosphate Synthetase 1 Deficiency Identified by Whole Exome Sequencing

Diagnosis of the urea cycle disorder (USD) carbamoyl-phosphate synthetase 1 (CPS1) deficiency (CPS1D) based on only the measurements of biochemical intermediary metabolites is not sufficient to properly exclude other UCDs with similar symptoms. We report the first Korean CPS1D patient using whole exome sequencing (WES). A four-day-old female neonate presented with respiratory failure due to severe metabolic encephalopathy with hyperammonemia (1,690 µmol/L; reference range, 11.2-48.2 µmol/L). Plasma amino acid analysis revealed markedly elevated levels of alanine (2,923 µmol/L; reference range, 131-710 µmol/L) and glutamine (5,777 µmol/L; reference range, 376-709 µmol/L), whereas that of citrulline was decreased (2 µmol/L; reference range, 10-45 µmol/L). WES revealed compound heterozygous pathogenic variants in the CPS1 gene: one novel nonsense pathogenic variant of c.580C>T (p.Gln194*) and one known pathogenic frameshift pathogenic variant of c.1547delG (p.Gly516Alafs*5), which was previously reported in Japanese patients with CPS1D. We successfully applied WES to molecularly diagnose the first Korean patient with CPS1D in a clinical setting. This result supports the clinical applicability of WES for cost-effective molecular diagnosis of UCDs.

Neonatal-onset carbamoyl phosphate synthetaseⅠdeficiency:a case report and literature review / 临床儿科杂志

Objective To explore the clinical characteristics of neonatal-onset carbamoyl phosphate synthetase I deficiency (CPS1D). Methods Clinical data and result of genetic detection of one neonate with CPS1D were retrospectively analyzed. The pertinent literature was reviewed. Results A 3-day old girl, with onset symptoms of nonspecific performance, such as poor feeding, less activity, tachypnea, and seizures. After fasting, anti-infection, and respiratory support etc. the condition was improved. However, the condition deteriorated and developed rapidly after feeding restarted. MRI showed extensive cerebral white matter lesions. Blood ammonia?>?500 μmol/L. Gene detection found two heterozygous mutations in pathogenic gene CPS1 in twentieth exon of c.2407C?>?G (p.803, R, G) and fourth exon C.323G?>?A (p.108, G, E), according to which CPS1D was diagnosed finally. Conclusions For neonate with normal birth, had feeding difficulty, seizures, and consciousness disorder after establishment of normal feeding, if blood ammonia level significantly increased, the blood and urine amino acids analysis and gene detection should be performed to confirm the diagnosis.

Impact of CPS1 Gene rs7422339 Polymorphism in Argentine Patients With Hyperhomocysteinemia

Abstract Carbamoyl phosphate synthetase 1 (CPS1) is a key gene in the first step of urea cycle and has been correlated with nitric oxide level and vascular smooth muscle activity. A functional single-nucleotide polymorphism C/A at position 4217 in CPS1 (National Center for Biotechnology Information SNP database no. rs7422339, T1405N) was reported to be associated with high homocysteine (Hcy) plasma values. Although genetic variants of methylenetetrahydrofolate reductase (MTHFR) gene are known to influence Hcy concentration, other genetic determinants of Hcy remain largely unknown. The association between the CPS1 rs7422339 and the risk of hyperhomocysteinemia in Latin American populations is unknown. Here, we study this association in 100 patients having hyperhomocysteinemia without MTHFR c.677C>T polymorphism and 100 controls. CPS1 rs7422339 was studied using polymerase chain reaction and enzymatic restriction. Comparisons of the CPS1 rs7422339 genotype distributions revealed a significant difference between groups (P = 2.3 × 10−3). Patients carrying polymorphic allele showed almost 3 times higher risk (odds ratio [OR] = 2.47) of hyperhomocysteinemia than wild-type allele, suggesting that rs7422339 SNP is associated with high Hcy levels in the Argentine population.

PREPARATION OF ~(35)S-LABEJJED CPS_1 cDNA PROBE FOR IN SITU HYBRIDIZATION / 解剖学报

The carbamyl phosphate synthetase I (CPS,) cDNA probe labelled with alpha ~(35)S-dATP was obtained by using modified nick translation technigue. The specific radioactivity of the obtained probe reached 0.9-1.5?10~8cpm/ug DNA. This probe could be satisfactorily used in RNA-DNA in situ hybrioization for detecting the gene expression of CPS_1 in liver tissue sections. The advantages of using ~(35)S instead of ~(32)P and ~3H for labelling DNA probe were discussed.

Extraction of Cuttlebone polysaccharides and purification of their active component CPS-1 / 第二军医大学学报

Objective:To extract the active polysaccharides from traditional Chinese herb-cuttlebone and to purify cuttlebone polysacchride salts 1(CPS-1),an active component of crude polysaccharides,so as to obtain refined natural active polysaccharides.Methods: Hot-water extraction method was optimized by orthogonal designing and was used to extract crude polysaccharides from cuttlebone.The total sugar contents of crude polysaccharides were determined.DEAE Sepharose F.F column and Sepharose CL-6B column were applied to separate CPS-1 from the crude polysaccharides.The active components were determined by animal experiments and Sephacryl S-300 column was used for further purification of CPS-1.HPLC was used to determine the purity of refined CPS-1 and the molecular weight of CPS-1 was determined by polysaccharides standard curve.Results: Crude polysaccharides were successfully extracted from cuttlebone.After purification with DEAE Sepharose F.F column,Sepharose CL-6B column and Sephacryl S-300 column and activity study,refined CPS-1 with average molecular weight(1?10~6) was obtained,and the sugar content reached 93.6%.Conclusion: Different extraction conditions have different extraction results for crude polysaccharides and different separation materials can separate the mixed polysaccharides by their molecular weights or charge characteristics.CPS-1 is a natural active polysaccharide extracted from cuttlebone.