Genetic diagnosis of a Chinese pedigree affected with neonatal argininosuccinic aciduria / 中华医学遗传学杂志

Objective@#To explore the genetic basis of a neonate with argininosuccinic aciduria (ASA).@*Methods@#A neonate with lethargy and food refusal was admitted. The patient had myoclonus, myasthenia, uroschesis, irregular breathing and paroxysmal ventricular tachycardia, and died at 75 hours after birth. Laboratory test showed marked increase in blood ammonia (1249.8 μmol/L). Peripheral blood samples of the patient, her parents and sister were collected and subjected to trio whole-exome sequencing.@*Results@#Whole-exome sequencing revealed that the patient has carried compound heterozygous mutations of the argininosuccinate lyase (ASL) gene, namely c. 425(exon5)_c.426(exon5) insAGCTCCCAGCT (p.Thr142Thrfs*37) and c. 626(exon8)delT (p.Leu209Argfs*42). The patient was diagnosed as ASA caused by ASL gene mutations. Her parents and her elder sister were heterozygous carriers of the above mutations and had a normal phenotype.@*Conclusion@#ASA is a severe congenital genetic metabolic disease and can manifest as onset of hyperammonemia in neonates. The clinical diagnosis is difficult and ASL gene testing may be helpful.

Intron mutations of argininosuccinate lyase (ASL) gene exist in a family with argininosuccinic aciduria / 临床检验杂志

Objective@#To perform gene detection and gene mutation analysis in a family with inherited metabolic diseases characterized as increased citrulline (Cit) by the MS/MS assay. @*Methods@#The peripheral blood samples were collected from the family members, and genomic DNA was extracted for gene diagnosis, which was performed by the whole exon sequencing method. The novel mutation gene was cloned into pcDNA3.1(+) vector, and its pathogenicity was verified by the Mini-gene assay in cultured cells in vitro. @*Results@#The clinical diagnosis of the proband as argininosuccinic aciduria (ASA) was clear. Two pathogenic mutations, c.281G＞T (p.Arg94Leu) and c.208-15 T＞A, were detected in the argininosuccinate lyase (ASL) gene, and they were not reported previously. The Mini-gene expression in vitro confirmed that c.208-15 T＞A could cause aberrant splicing, resulting in the retention of 13 bp in intron 2. @*Conclusion@#Two new pathogenic mutations of ASL gene, c.208-15 T＞A and c.281G＞T, are found in an ASA family, which enriches the mutation profile of ASL gene. The Mini-gene assay is a simple and effective tool for the research of intron mutations.

A case of neonatal death due to argininosuccinic aciduria / 临床儿科杂志

Objectives To report the ifrst Chinese case of early onset argininosuccinic aciduria. Methods A girl aged three days was admitted because of vomiting and lethargy from the second day of life. General laboratory examination, blood amino acids analysis, urine organic acids tests and gene studies were performed for the diagnosis. Results Severe hyperam-monemia, liver dysfunction, metabolic acidosis, hypokalemia and hypocalcemia were found. Bood citrulline was extremely elevated (1098.12μmol/L vs normal range 5 to 25μmol/L), while blood arginine was decreased. Urine orotic acid, uracil and argininosuccinic acid were signiifcantly elevated. Two known heterozygosis mutations on ASL gene, c.544C>T (p.R182X) and c.706C>T (p.R236W), conifrmed the diagnosis of argininosuccinic aciduria. Unfortunately, protein-restricted diet with L-arginine supplement showed no effect. The patient died at the 23th day of life. Conclusions Argininosuccinic aciduria is a severe inherit-ed metabolic disorder. Clinical diagnosis is dififcult. It is characterized biochemically by severe citrullinemia. Urine organic acids analysis and ASL gene analysis are important for the differential diagnosis. In this study, a case of neonate death due to early-on-set argininosuccinic aciduria was diagnosed by post-mortem investigation. ASL gene study is helpful for the genetic counseling and prenatal diagnosis of the disease.