Study on blood carnitine metabolism and its influencing factors in premature infants / 国际儿科学杂志

Objective:To explore the characteristics and influencing factors of blood carnitine metabolism in premature infants.Methods:A retrospective analysis of 37 037 neonates with negative results of genetic metabolic disease screening at Guangxi Newborn Disease Screening Center from 2018 to 2021, of which 34 517 normal full-term infants were the control group and 2 520 preterm infants were the research group.According to gestational age, the preterm infants were further divided into three groups: extremely preterm group( n=232), moderately preterm group( n=324)and late preterm group( n=1 964). According to birth weight, they were divided into three groups: very low birth weight group( n=188), low birth weight group( n=1 276)and normal birth weight group( n=1 056). According to blood collection time, they were divided into three groups: 3~7 days group( n=1 990), 8~14 days group( n=342) and 15~28 days group( n=188). Tandem mass spectrometry was used to detect the levels of 31 carnitines in dried blood spots and analyze the differences in the levels of metabolic indicators in each group. Results:Carnitine levels in preterm infants are most affected by gestational age.Adjusting the physiological and pathological conditions of premature infants and other related factors, grouped by gestational age, there were differences in the levels of 31 carnitines among the groups(all P<0.05), the smaller the gestational age, the greater the difference in carnitine levels; grouped by blood collection time, there were statistically significant differences in carnitine levels between preterm infants with different blood collection age groups and full-term 3~7 days groups(all P<0.05), and showing age-related; there are differences among 31 carnitines grouped by body weight(all P<0.05), the smaller the body weight, the greater the difference in carnitine levels.Combined with the analysis of gestational age, birth weight and blood collection date, 17 indicators including C0, C2, C3, C4, C6DC, C10, C10∶1, C12, C12∶1, C14, C14∶1, C14OH, C16, C16∶1, C18, C18∶1 and C18∶1OH are important biomarkers of carnitine metabolism in premature infants. Conclusion:Carnitine in premature newborns has different metabolic differences at different gestational ages, birth weights and blood collection ages, which provides a strong basis for establishing reference standards and interpretation of preterm infants in the laboratory in this region, and provides reasonable and effective early diagnosis and treatment for clinical practice.Meanwhile, it provides an optimized program for timely detection of carnitine deficiency and carnitine supplementation to improve nutrition of premature infants.

Analysis of metabolic profile and genetic variants for newborns with primary carnitine deficiency from Guangxi / 中华医学遗传学杂志

OBJECTIVE@#To analyze the metabolic profile and genetic variants for newborns with primary carnitine deficiency (PCD) from Guangxi, China.@*METHODS@#From January 2014 to December 2019, 400 575 newborns from the jurisdiction of Guangxi Zhuang Autonomous Region Newborn Screening Center were subjected to tandem mass spectrometry (MS/MS) analysis. Newborns with positive results for PCD and their mothers were recalled for retesting. Those who were still positive were subjected to sequencing of the SLC22A5 gene.@*RESULTS@#Twenty-two newborns and 9 mothers were diagnosed with PCD, which gave a prevalence rate of 1/18 208. Sequencing of 18 newborns and 4 mothers have identified 14 types of SLC22A5 gene variants, with the common ones including c.51C>G (10/44, 22.7%), c.1195C>T (9/44, 20.5%) and c.1400C>G (7/44, 15.9%), The c.517delC(p.L173Cfs*3) and c.1031C>T(p.T344I) were unreported previously and predicted to be pathogenic (PVS1+PM2_supporting+PM3+PP4) and likely pathogenic (PM1+PM2_supporting+PM3+PP3+PP4) based on the American College of Medical Genetics and Genomics standards and guidelines.@*CONCLUSION@#c.51C>G, c.1195C>T and c.1400C>G are the most common variants underlying PCD in Guangxi.

Effects of different thyroid stimulating hormone cut-off values on the screening of congenital hypothyroidism in newborns in Guangxi / 中华地方病学杂志

Objective To analyze the effects of different thyroid stimulating hormone (TSH) cut-off values on the screening of congenital hypothyroidism (CH) in newborns in Guangxi.Methods The TSH results of 83 608 newborns tested by Genetic Screening Processor (GSP) from the Genetic Metabolism Center of the Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region from May 2017 to April 2018 were collected.Using the percentile method and the receiver operating characteristic (ROC) curve method,the TSH cut-off values were calculated and compared with the assumed cut-off values 9.00 or 10.00 mU/L,to analyze the effects of four different TSH cut-off values on CH screening.Results Using GSP,the TSH results of 83 608 newborns showed a positive skewed distribution,TSH cut-off value of the percentile method (P99) was 7.96 mU/L,836 cases were suspicious,43 cases were diagnosed with CH (6 cases were missed diagnosis),and 65 cases were high TSH (21 cases were missed diagnosis);TSH cut-off value of the ROC curve method was 6.45 mU/L,1 480 case were suspicious,49 cases were diagnosed with CH,and 86 cases were high TSH,both were no missed diagnosis;when TSH cut-off values were 9.00 or 10.00 mU/L,the suspicious were 478 and 305 cases,respectively,and the confirmed CH were 37 and 35 cases (missed diagnosis were 12 and 14 cases,respectively),high TSH were 46 and 33 cases (missed diagnosis were 40 and 53 cases,respectively).The CH incidence of the ROC curve method was compared with the percentile method and using the cut-off values 9.00 and 10.00 mU/L,the differences were statistically significant (P ＜ 0.05).Conclusions The GSP and ROC curve method were used to successfully establish the TSH cut-off value on the screening of CH in newborns in Guangxi.The cut-off value can not only ensure the accuracy of screening,but also avoid missed diagnosis and reduce birth defects.

Gene screening of neonatal non-syndromic hereditary hearing loss in Guangxi / 重庆医学

Objective To use the matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) technique for detecting the mutation gene of neonatal non-syndromic hereditary hearing impairment gene in Guangxi and to investigate its effectiveness and feasibility in clinical application.Methods A total of 7 100 newborns were performed the hearing preliminary screening and secondary screening by adopting AABR.The genomic DNA was extracted by the heel blood spot.Twenty mutation characteristics of 4 deaf predisposing genes were detected by MALDI-TOF-MS.Results The pass rate of hearing screening in 7 100 newborns was 97.11％ (6 895/7 100),the positive rate of neonatal gene mutation was 3.54％ (251/7 100),in which the GJB2 gene mutation was in 131 cases,the carrying rate was 1.84％,235delC heterozygous mutation was in 108 cases.SLC26A4 gene mutation was in 93 cases,which dominated by 1229C＞T heterozygous mutation and IVS7-2A＞G heterozygous mutation,mtDNA12SRNA gene mutation was in 16 cases and GJB3 gene mutation was in 11 cases.Conclusion Adopting the MALDI-TOF-MS screening technique can increase the detection rate of hot point mutation in common deaf related genes and discover neonatal genetic NSHI from molecular level and provides the corresponding geneticconsulting guidance for early finding and predicting deaf occurrence,and formulating the interventional measures.