Screening strategy and genetic mutation analysis of citrin deficiency among newborns in Xuzhou / 中国新生儿科杂志

Objective:To study the incidence, clinical features and genetic mutation profiles of neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) using screening strategy.Methods:From September 2015 to September 2020, neonates in Xuzhou area were prospectively screened for genetic metabolic diseases using tandem mass spectrometry. Suspected infants were further confirmed using urinary organic acid test and SLC25A13 gene mutation analysis. The clinical manifestations, biochemical and gene mutation results, treatment and prognosis of the confirmed cases were analyzed.Results:A total of 468,494 live-birth newborns were screened with 112 cases suspected and 95 cases received urinary organic acid test and SLC25A13 gene mutation analysis. 13 cases of NICCD were diagnosed with a prevalence of 1/36,038. Most confirmed cases presented with delayed disappearance of neonatal jaundice, feeding difficulties and poor weight gain. Biochemical changes included increased bile acid, abnormal liver enzymes, increased alpha-fetoprotein, hypoglycemia, decreased hemoglobin, abnormal coagulation function and increased blood ammonia. Tandem mass spectrometry showed increased citrulline, methionine, arginine, tyrosine and phenylalanine, and in some cases with slightly increased acylcarnitine. Urine organic acid analysis mainly showed increased 4-hydroxyphenyllactic acid and 4-hydroxyphenylpyruvate. All confirmed cases received genetic mutation tests and a total of 13 mutation loci were detected, including c.852_855delTATG, c.511dupG, c.1638_1660dup, IVS16ins3kb, c.1078C>T, c. 615+5G>A, c.742G>A, c.44G>A, c.1311+1G>A, c.1399C>T, c.889G>T, c.1177+1G>A, c.1841+3_1841+4del, among which, c.852_855delTATG was the most common one. A total of 5 novel mutation loci were discovered in this study with c.1841+3_1841+4del, c.511dupG and c.889G>T predicted as pathogenic variants. Special formula of lactose-free and fortified medium-chain triglyceride (MCT) were used in confirmed cases and most of the symptoms were relieved within 1 year and abnormal indicators significantly improved.Conclusions:The prevalence of NICCD in Xuzhou was 1/36,038. c.852_855delTATG mutation is the most frequent one. Five novel mutation loci are discovered, expanding the SLC25A13 gene mutation spectrum. Most infants with NICCD have a good prognosis, requiring early diagnosis, treatment and life-long follow-up.

Clinical study on screening carnitine absorption deficiency in neonates by tandem mass spectrometry / 中华实用儿科临床杂志

Objective@#To estimate the levels of free carnitine and acylcarnitine in neonates, and summarize the incidence and clinical characteristics of carnitine absorption deficiency in Xuzhou.@*Methods@#Between November 2015 and December 2017, 216 903 newborns were recruited with carnitine absorption deficiency screened via tandem mass spectrometry in Xuzhou.They were divided into different groups according to gestational age, birth body weight, blood collecting time and season, in which the group with gestational age <37 weeks was selected as the premature delivery group, and the group with gestational age 37-41+ 6 weeks as the normal gestational age group for gestational age analysis, while the group with the birth body mass <2 500 g was selected as low birth body mass group and the group with the birth body mass of 2 500-3 999 g as normal birth body mass group for body mass analysis.SPSS 16.0 software was used for data analysis to clarify the influence of the above factors on the detection of carnitine indexes by tandem mass spectrometry.DNA sequencing was performed to confirm the diagnosis and analyze the relevant pathogenic genotypes in children with positive screening, and these confirmed individuals were followed up.@*Results@#There was no statistical difference in the levels of C3, C8 and C102 between preterm infants and normal body mass infants in the gestational age group(all P>0.05), but other carnitine levels had statistically significant differences(all P<0.05). The difference of C102 level between the different birth weight groups was not statistically significant(P>0.05), but that of other carnitine levels were statistically significant(all P<0.05). There was no significant difference in the level of C182 between different blood collection time(P>0.05). The levels of free carnitine and acylcarnitine between the different season groups had statistically significant differences(all P<0.05). Primary carnitine deficiency was diagnosed in 10 cases, including 7 cases of maternal carnitine absorption deficiency.The incidence in Xuzhou was approximately 121 690.The pathogenic genotype showed a specific regional distribution characteristic in Xuzhou, in which pathogenic mutation type c. 1400C >G was the most common one.@*Conclusions@#Some factors play a role in neonatal screening for carnitine absorption deficiency by tandem mass spectrometry including gestational age, birth body weight, blood collecting time and season.Pathogenic genes present a regional characteristic in Xuzhou and maternal carnitine absorption deficiency with a higher rate, the clinical attention should be paid to screening for maternal carnitine absorption deficiency.

Clinical study on screening carnitine absorption deficiency in neonates by tandem mass spectrometry / 中华实用儿科临床杂志

Objective To estimate the levels of free carnitine and acylcarnitine in neonates,and summarize the incidence and clinical characteristics of carnitine absorption deficiency in Xuzhou. Methods Between November 2015 and December 2017,216 903 newborns were recruited with carnitine absorption deficiency screened via tandem mass spectrometry in Xuzhou. They were divided into different groups according to gestational age,birth body weight, blood collecting time and season,in which the group with gestational age <37 weeks was selected as the premature de-livery group,and the group with gestational age 37-41+6 weeks as the normal gestational age group for gestational age analysis,while the group with the birth body mass <2 500 g was selected as low birth body mass group and the group with the birth body mass of 2 500-3 999 g as normal birth body mass group for body mass analysis. SPSS 16. 0 software was used for data analysis to clarify the influence of the above factors on the detection of carnitine indexes by tandem mass spectrometry. DNA sequencing was performed to confirm the diagnosis and analyze the relevant pathogenic geno-types in children with positive screening,and these confirmed individuals were followed up. Results There was no sta-tistical difference in the levels of C3,C8 and C10: 2 between preterm infants and normal body mass infants in the ges-tational age grou(p all P>0. 05),but other carnitine levels had statistically significant differences(all P<0. 05). The difference of C10: 2 level between the different birth weight groups was not statistically significant(P>0. 05),but that of other carnitine levels were statistically significant(all P<0. 05). There was no significant difference in the level of C18: 2 between different blood collection time(P>0. 05). The levels of free carnitine and acylcarnitine between the different season groups had statistically significant differences(all P<0. 05). Primary carnitine deficiency was diag-nosed in 10 cases,including 7 cases of maternal carnitine absorption deficiency. The incidence in Xuzhou was approxi-mately 1: 21 690. The pathogenic genotype showed a specific regional distribution characteristic in Xuzhou,in which pathogenic mutation type c. 1400C >G was the most common one. Conclusions Some factors play a role in neonatal screening for carnitine absorption deficiency by tandem mass spectrometry including gestational age,birth body weight, blood collecting time and season. Pathogenic genes present a regional characteristic in Xuzhou and maternal carnitine absorption deficiency with a higher rate,the clinical attention should be paid to screening for maternal carnitine absorp-tion deficiency.

Screening and SLC22A5 gene mutations of the patients with primary carnitine deficiency / 中华实用儿科临床杂志

Objective To investigate the clinical features and SLC22A5 gene mutation types in patients with primary carnitine deficiency(PCD).Methods The free carnitine(CO) and acylcarnitine levels in the blood of 210 908 neonates from newborn screening program and 576 children with suspected clinical inherited metabolic diseases were measured by using liquid chromatography tandem mass spectrometry method during September 2015 to December 2017,after that the SLC22A5 gene mutations were analyzed in the children with low CO level and the diagnosis was made.The clinical characteristics,laboratory findings,genotypes,treatment and prognosis were retrospectively analyzed in patients.Paired sample t test was used to compare the biochemical indexes of patients before and after the treatments.Results Ten children were diagnosed with PCD(9 cases from newborn screening program,1 case from clinical patients),and 7 children were diagnosed with maternal carnitine deficiency.After treatment with oral Levocarnitine,the free carnitine and acylcarnitine of the patients returned to the normal levels.The clinical symptoms disappeared in 1 patient out of clinical patients,and the other 16 patients from newborn screening program were asymptomatic and showed normal growth and development.Seventeen patients got genetic analysis,and 10 types of mutations were found,including c.1400C ＞ G,c.1462C ＞ T,c.797C ＞ T,c.95A ＞ G,c.92C ＞ T,c.1093A ＞ C,c.761G ＞ A,c.865C ＞ T,c.428C ＞ T,c.1195C ＞ T,among which two of them (c.1093A ＞ C and c.92C ＞ T) were novel mutations.The most common mutation of SLC22A5 gene was c.1400C ＞ G.Conclusions Liquid chromatography tandem mass spectrometry technology is sufficient to screen newborns and maternal carnitine deficiency,and the c.1400C ＞ G mutation is found at the highest frequency in Xuzhou area.If patients receive early treatment,they may have a good prognosis.