Application of liquid chromatography-tandem mass spectrometry (LC-MS/MS) in screening of high risk children with inherited metabolic diseases in northern China

A preliminary investigation of amino acid and acylcarnitine levels in neonates from the Tibet autonomous

Background: The purpose of the study was to investigate the levels of amino acids and acylcarnitines in newborns of the Tibet Autonomous Region for the first time and to provide an experimental basis for the diagnosis of genetic metabolic diseases. Methods: We detected concentrations of 43 kinds of amino acids, acylcarnitines and succinylacetone in the dried blood spots of 18482 newborns using liquid chromatography tandem mass spectrometry and diagnose the case by gene sequencing. We compared the indexes between Tibet and our lab, where most data come from an inland area and Han Chinese people. Then we compared amino acid and acylcarnitine levels of seven regions in Tibet and explored their impact factors. Results: We described the levels of amino acids and acylcarnitines in Tibet newborns using 95% confidence intervals. The distribution of amino acid and acylcarnitines were different in Tibet. Conclusion: This study has contributed to filling in the blanks of Tibet newborn screening, which should be considered in the newborn metabolic disease screening in this area.

Prevalence of methylmalonic acidemia among newborns and the clinical-suspected population: a meta-analyse

IMPORTANCE

Knowing the scale of rare inborn errors is important for screening and resource allocation. Evidence on the prevalence of methylmalonic acidemia (MMA) among newborns and the clinical-suspected population from large-scale screening programs needs to be systematically synthesized.

OBJECTIVE

To estimate the worldwide prevalence of MMA for newborns and the clinical-suspected population and explore the differences in different regions, periods, and diagnostic technologies.

DATA SOURCES

MEDLINE, Embase, CRD, Cochrane Library, Scopus, CINAHL, and PROSPERO. Study Selection: All studies reporting the epidemiology characteristics of MMA were selected.

DATA EXTRACTION AND SYNTHESIS

Characteristics of study, subjects, and epidemiology were extracted, random-effect models were used for meta-analyses.

MAIN OUTCOME AND MEASURE

Pooled prevalence of MMA.

RESULTS

This study included 111 studies. The pooled prevalence of MMA worldwide was 1.14 per 100,000 newborns (1516/190,229,777 newborns, 95% CI: 0.99-1.29) and 652.11 per 100,000 clinical-suspected patients (1360/4,805,665 clinical-suspected individuals, CI: 544.14-760.07). Asia and Africa got a higher pooled prevalence of MMA. The prevalence of MMA in newborns increased through the years, while that in the clinical-suspected population decreased. Collecting blood ≥ 72 h after birth had a higher pooled prevalence of MMA than collecting during 24 h-72 h after birth. The combining-use of MS/MS and GC/MS had a higher pooled prevalence than the single-use of MS/MS or GC/MS. Prevalence of cbl C, mut, cbl B, cbl A, isolated MMA, combined MMA and homocystinuria, vitamin B12-responsive MMA was synthesized.

CONCLUSIONS AND RELEVANCE

Prevalence of MMA among newborns was extremely low, but considerably high in the clinical-suspected population, indicating the need for more efficient newborn screening strategies and closer monitoring of the high-risk population for the early signs of MMA. Asia and Africa should attach importance to the high prevalence of MMA. Further diagnostic tests were recommended for the combining-use vs single-use of MS/MS and GC/MS and for collecting blood after 72 h vs during 24-72 h after birth.

Screening oligonucleotide sequences for silver staining and d-galactose visual detection using RCA silver staining in a tube

Oligonucleotides were screened for strongly silver-stained repetitive sequences. An 'AG'-clustered purine sequence showed strong staining, and the staining density can be compromised by disrupting the continuity of the 'AG'-clustered sequence. The staining-favored sequence was then employed in rolling circle amplification (RCA) for its product detection. A tube-staining method was developed for convenient and visual RCA assay. Moreover, by introducing GalR into RCA, d-galactose was detected by RCA tube-staining with naked eyes without any equipment. About 10 mM d-galactose can be easily identified, and the detection of d-galactose was specific in comparison with that of several other monosaccharides.

Impact of inborn errors of metabolism on admission in a neonatal intensive care unit: a 4-year report

Inborn errors of metabolism (IEM) have greater repercussions in neonatology units. The aim of our study was to evaluate the impact of IEM in a neonatal intensive care unit (NICU) and the resources required to care for these neonates. All patients with IEM admitted in our unit during a 4-year period were evaluated for specific diagnosis, demographic data, clinical features, biochemical characteristics at admission, need for mechanical ventilation, use of extracorporeal removal therapy, and outcome at NICU discharge. The study group comprised 2742 infants, 39 of which required admission to the NICU (1.42% of admissions) because of severe symptoms and/or newborn screening. Five of the 39 had an earlier diagnosis and treatment because of expanded newborn screening. The average age at admission was 5 days [interquartile range (IQR, 3-9 days)] and the median length of stay in the NICU for the study population was 5 days (IQR, 3-12 days). Aggressive support was often necessary (extracorporeal removal therapy, mechanical ventilation). Ten patients died; thus the death rate was 25.6%. Overall mortality in the NICU was 10.4% during the study period. These observations shown that IEM may be very common in our population. Most patients with IEM admitted to a NICU require aggressive support (including mechanical ventilation and extracorporeal removal therapies), and consume significant resources for relatively shorter stays.