Newborn screening for ornithine transcarbamylase deficiency in Zhejiang Province and the follow-up analysis / 中华实用儿科临床杂志

Objective:To investigate the incidence, clinical characteristics and prognosis of ornithine transcarbamylase deficiency(OCTD) in newborns in Zhejiang Province.Methods:A retrospective research was conducted.A total of 4 261 036 newborns from Department of Genetics and Metabolism, Children′s Hospital, Zhejiang University School of Medicine, between January 2009 and December 2021 were screened for inherited metabolic disorders using tandem mass spectrometry.OCTD was confirmed by urine organic acid and OTC gene analysis.Patients with OTCD received guidance on diet and lifestyle management, and were treated with citrulline and arginine.Long-term follow-up was performed.Their growth and intellectual development were evaluated. Results:A total of 7 patients with OCTD were diagnosed, with an incidence of 1.6/1 million.All patients were males.Two patients had neonatal-onset OCTD, and the other 5 had late-onset OCTD.Symptoms occurred several times in 6 patients, inducing hyperammonemia and hepatic impairment.One patient had no clinical manifestation.One patient died in the neonatal period.Blood citrulline levels were decreased in 7 patients to varying degrees.Uracil levels were increased in 4 patients, and 1 of them was complicated with elevated orotic acid levels.All patients had hemizygote variations in the OTC gene, including 6 missense variations(c.604C>T, c.386G>A, c.779T>C, c.1019C>T, c.594C>G, c.931G>A) and 1 intron variation(c.514-35C>G). Two variants(c.594C>G, c.514-35C>G) were never reported previously. Conclusions:The OTCD incidence by newborn screening is low with 1.6/1 million in Zhejiang province.All patients are males and present hypocitrullinemia.The clinical manifestations of OTCD are highly heterogeneous.The neonatal-onset form is severe and survivors always suffer serious sequelae.The late-onset form is mostly manifested with hyperammonemia and hepatic impairment.There may be association between phenotype and genotype.Two novel OTC variants are identified, which further expands the mutational spectrum.

A multi-center study of biochemical and hotspot gene screening for neonatal genetic metabolic diseases / 中华实用儿科临床杂志

Objective:To investigate the efficiency of biochemical screening and hotspot gene screening in the detection of neonatal inherited metabolic diseases.Methods:This was a prospective multi-center study.The study was carried out on 21 442 neonatal samples collected from 12 hospitals in 10 provinces from November 2020 to November 2021.The results of biochemical screening and hotspot gene screening were analyzed jointly.Biochemical screening methods included glucose-6-phosphate dehydrogenase deficiency enzyme activity assay and neonatal tandem mass spectrometry.Genetic screening analysis involved 135 genes associated with 75 neonatal diseases.Results:Of all the 21 442 neonates enrolled in the study, 21 205 were subject to biochemical screening.A total of 813 cases were positive in the initial screening, and 0.45% of them (95 cases) were diagnosed after recall.All the 21 442 neonates underwent gene screening.About 168 positive cases were detected in the initial screening, and 0.73% (156 cases) of them were confirmed finally.Biochemical and genetic screening improved the detection sensitivity of such diseases as primary carnitine deficiency, neonatal intrahepatic cholestasis caused by citrin deficiency, and 2-methylbutyrylglycinemia.Moreover, biochemical and genetic screening enabled the detection of more diseases, including the common single-gene genetic diseases such as thalassemia and Wilson disease.Conclusions:In neonatal screening, the combination of biochemical screening and gene screening expands the number of diseases detected and improve screening efficiency.

Screening for hereditary tyrosinemia and genotype analysis in newborns / 浙江大学学报·医学版

OBJECTIVE@#To analyze the results of screening for hereditary tyrosinemia (HT) in newborns and its clinical features and genotype.@*METHODS@#The HT screening was conducted among 2 188 784 newborns from November 2013 to November 2018. The tyrosine (TYR)/ succinylacetone (SA) levels were detected by tandem mass spectrometry (MS-MS). The clinical characteristics, genetic results and following up data of identified patients were analyzed.@*RESULTS@#The normal ranges (0.5%-95.5%) of TYR and SA were 34.5-280.0 μmol/L and 0.16-2.58 μmol/L, respectively. Three HT cases were confirmed with a detection rate of 1∶729 595. There was 1 case of tyrosinemia type Ⅰ (HTⅠ) (homozygous variations of c.455G>A in gene), 1 case of tyrosinemia type Ⅱ(HTⅡ) (heterozygous variations of c.890G>T and c.408+1G>A in gene), and 1 case of tyrosinemia type Ⅲ (HT Ⅲ) (homozygous variations of c.257T>C in gene). The variations of c.890G>T, c.4081G>A of and c.257T>C of were novel. The positive predictive value of the screening was 3.4%. Case 1 (HTⅠ) with TYR and SA values of 666.9 μmol/L and 3.87 μmol/L respectively, presented cholestasis, mild elevated of liver enzyme and lactic acid, who were although fed with TYR and phenylalanine free milk, but died at 2 months of age. Case 2 (HTⅡ) with higher TYR (625.6 μmol/L) and normal SA at screening, received medical milk treatment; during the 7 months of follow-up the baby showed normal score of Bayley assessment and normal TYR without eye and skin symptoms. Case 3 (HT Ⅲ) with TYR of 1035.3 μmol/L and normal SA at screening; during the 29 months of follow-up the value of TYR fluctuated from 532.1 μmol/L to 1060.3 μmol/L due to irregular medical milk treatment, while the score of Bayley assessment was normal.@*CONCLUSIONS@#HT is rare in the southern Chinese population, and the gene spectrum is scattered. Early treatment with nitisinone is recommended in children with HTⅠ, otherwise the prognosis is poor; the prognosis of children with HTⅡ is good when early treated with special diet; the prognosis of children with HTⅢ needs to be determined with more data.

Analysis of UQCRB gene mutation in a child with mitochondrial complex III deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To delineate the clinical, biochemical and genetic mutational characteristics of a child with mitochondrial complex III deficiency.</p><p><b>METHODS</b>Clinical information and results of auxiliary examination of the patient were analyzed. Next-generation sequencing of the mitochondrial genome and related nuclear genes was carried out. Suspected mutation was confirmed in both parents with Sanger sequencing. Heterozygous deletion was mapped with chromosomal microarray analysis and confirmed with real-time PCR.</p><p><b>RESULTS</b>The patient presented with vomiting, polypnea, fever, metabolic acidosis, hyperlactatemia, hypoglycemia, dysfunction of coagulation and immune system, in addition with increased lactate dehydrogenase and creatine kinase isoenzyme. Elevation of blood alanine and acylcarnitines as well as urinary ketotic dicarboxylic acid were also noted. The patient also presented development delay, mental retardation and hypotonia. Sequence analysis revealed two mutations in the nuclear gene UQCRB, which included a previously reported frameshift mutation c.306_309delAAAA(p.Arg105Lysfs*22) and a novel large deletion encompassing the entire UQCRB gene.</p><p><b>CONCLUSION</b>The clinical, biochemical and gene mutation characteristics of a child with mitochondrial complex III deficiency caused by mutations of the UQCRB gene have been delineated.</p>

Analysis of newborn screening for galactosemia and genotype-phenotype of confirmed galatosemia cases / 中华儿科杂志

Objective@#To investigate the prevalence of galactosemia(GAL), and the characteristics of genotype and phenotype of newborns who were confirmed with GAL in newborn screening in Zhejiang province.@*Method@#The number of all live births, newborn screened infants and all clinical data of confirmed newborns with GAL from October 2013 to March 2015 were retrospectively analyzed by reviewing the data of Zhejiang Province screening center database. And the characteristics of genes and the clinical data of GAL cases who were confirmed by correlative gene test and enzyme activity measurement were analyzed.@*Result@#The prevalence of GAL in Zhejiang province was 1/189 857. Among them, there was 1 case confirmed with GAL typeⅠ (prevalence, 1/759 428), with mutations of c. 904+ 1G>T and c. 687G>A, the enzyme activity of galactose-1-phosphate uridyltransferase (GALT) was 56.4% of controls. And there was 1 case of GAL typeⅡ(prevalence, 1/759 428), with mutations of c. 85G>T and c. 502G>A. There were 2 cases confirmed with GAL type Ⅲ(prevalence, 1/379 714), with mutations of c. 505C>T, c. 452G>A, c. 280G>A and c. 925G>A, the enzyme activity of UDP-galactose-4′-epimerase (GALE) were 42% and 38% of controls, respectively. All cases had different abnormal biochemical marks of liver function, and 1 case had combined hyperlactacidemia or hyperammonemia or increase of multiple kinds of amino acids, respectively. The newborn of GAL type Ⅱ had phacoscotasmus before treatment. All the cases were fed with lactose free milk powder, and all the abnormal parameters were improved during following up.@*Conclusion@#The disease of GAL is rare in Zhejiang province, and its genotype distribution is scattered with comparatively mind clinical manifestations, and the cases with early treatment with lactose free milk powder have good prognosis. All cases needed to be treated and followed up for a life-long time. It is recommended that the high risk cases with GAL should be screened as soon as possible.