Recurrence of carbamoyl phosphate synthetase 1 (CPS1) deficiency in Turkish patients: Characterization of a founder mutation by use of recombinant CPS1 from insect cells expression

Defective hepatic bicarbonate production due to carbonic anhydrase VA deficiency leads to early-onset life-threatening metabolic crisis

“…Third, to prove the disease-causing role of all detected CA5A mutations, we developed an expression system based on insect cells, already proven valid by other groups to express other CA isoforms 19,20 and by our group to study another liver mitochondrial enzyme, CPS1. [21][22][23] We expressed the recombinant wild-type CAVA, all published and newly identified mutations, and three non-disease-associated variants, and we tested their enzyme activity and thermal stability. Finally, we described the clinical and biochemical features of the patients with CAVA deficiency.…”

Novel compound heterozygote variants: c.4193_4206delinsG (p.Leu1398Argfs*25), c.793C > A (p.Pro265Thr), in the CPS1 gene (NM_001875.4) causing late onset carbamoyl phosphate synthetase 1 deficiency—Lessons learned

“…CPS1 deficiency can be classified as neonatal- or late-onset, with neonatal-onset patients presenting with a potentially lethal hyperammonemia crisis days after birth, while late-onset CPS1 deficiency is usually associated with less severe manifestations [ 4 ]. This variation in disease may be due to the level of residual enzyme activity [ 11 ]. Patients diagnosed later in life often suffer cerebral insults and develop learning difficulties and mild intellectual impairment [ [12] , [13] , [14] ].…”

Precision medicine in rare disease: Mechanisms of disparate effects of N -carbamyl- l -glutamate on mutant CPS1 enzymes

“…The newly developed baculovirus/insect cell expression system, which can produce a large amount of the recombinant CPS1 with desired mutations, provides a useful tool to evaluate the residual activity, protein yield and stability of CPS1 mutants. This tool has been successfully used to study the disease-causing roles and pathogenic mechanism of various mutations in CPS1 [36,38,51–54]. …”

“…Thermal stability assays were performed in a 96-well plate format using a 7900 HT real-time PCR system (Applied Biosystem) to record changes in the fluorescence signal when the temperature was ramped from 298 K to 353 K to monitor thermal unfolding of proteins in the presence of a fluorescent dye, Sypro Orange (Invitrogen), as previously described [37,38]. Wells contained 6 μg of enzyme in 20 mM glycyl-glycine, pH 7.4, 20 mM KCl, 10% glycerol, and 50X SYPRO orange.…”