Clinical characteristics and genetic analysis of six children with carnitine palmitoyltransferase 2 deficiency. / å ­ä¾‹è‚‰ç¢±æ£•æ¦ˆé °åŸºè½¬ç§»é ¶2ç¼ºä¹ç—‡æ‚£å„¿ä¸´åºŠç‰¹å¾åŠåŸºå› å˜å¼‚åˆ†æž.

OBJECTIVES: To investigate the clinical characteristic and genetic variants of children with carnitine palmitoyltransferase 2 (CPT2) deficiency. METHODS: The clinical and genetic data of 6 children with CPT2 deficiency were retrospectively analyzed. The blood acylcarnitines and genetic variants were detected with tandem mass spectrometry and whole-exon gene sequencing, respectively. RESULTS: There were 4 males and 2 females with a mean age of 32 months (15 d-9 years) at diagnosis. One case was asymptomatic and with normal laboratory test results, 2 had delayed onset, and 3 were of infantile type. Three cases were diagnosed at neonatal screening, and 3 cases presented with clinical manifestations of fever, muscle weakness, and increased muscle enzymes. Five children presented with decreased free carnitine and elevated levels of palmitoyl and octadecenoyl carnitines. CPT2 gene variants were detected at 8 loci in 6 children (4 harboring biallelic mutations and 2 harboring single locus mutations), including 3 known variants (p.R631C, p.T589M, and p.D255G) and 5 newly reported variants (p.F352L, p.R498L, p.F434S, p.A515P, and c.153-2A>G). It was predicted by PolyPhen2 and SIFT software that c.153-2A>G and p.F352L were suspected pathogenic variants, while p.R498L, p.F434S and p.A515P were variants of unknown clinical significance. CONCLUSIONS: The clinical phenotypes of CPT2 deficiency are diverse. An early diagnosis can be facilitated by neonatal blood tandem mass spectrometry screening and genetic testing, and most patients have good prognosis after a timely diagnosis and treatment.

[Long-term outcome of hematopoietic stem cell transplantation in two children with Mucopolysaccharidosis].

OBJECTIVE: To explore the long-term efficacy of allogeneic hematopoietic stem cell transplantation (alloHSCT) in patients with Mucopolysaccharidosis (MPS), which has rarely been reported in China. METHODS: A 18-month-old boy and a 23-month-old girl undergoing alloHSCT for MPS VI and MPS IH Shanghai Children's Medical Center on March 30, 2006 and September 6, 2006 were selected as the study subjects. A busulfan-based myeloablative regimen was used as the conditioning regimen. Peripheral stem cells were respectively collected from a human leucocyte antigen (HLA) matched sibling carrier donor and a HLA 9/10 matched unrelated donor. Both patients were followed up for more than 15 years. The functions of internal organs before and after the transplantation were compared, and child 1 was also compared with his untreated brother and healthy brother. RESULTS: Both children have achieved full donor chimerism after the transplantation, and their enzymatic activities have remained stable. The enzymatic activity of the child 1 was slightly lower than normal but similar to that of his carrier donor, whilst that of the child 2 was normal. Both children have attended schools with good academic performance. Compared with his untreated brother, the respiratory function and hearing of child 1 have significantly improved. However, his orthopedic and cardiac disorders have still remained and required medical intervention. For child 2, her obstructive pulmonary disease was resolved and cognitive development was well preserved after the HSCT. Her heart disease has become stabilized and even improved with time, though her corneal clouding and skeletal malformation still required surgery. CONCLUSION: MPS patients can sustain long-term and stable enzymatic activities after successful alloHSCT. Compared with untreated patients, their health can be significantly improved, along with considerably prolonged survival, though the long-term efficacy of HSCT for different organs may vary to a certain extent.

Late-onset cblC defect: clinical, biochemical and molecular analysis.

BACKGROUND: cblC defect is the most common type of methylmalonic acidemia in China. Patients with late-onset form (>1 year) are often misdiagnosed due to heterogeneous symptoms. This study aimed to describe clinical characteristics and evaluate long-term outcomes of Chinese patients with late-onset cblC defect. METHODS: A total of 85 patients with late-onset cblC defect were enrolled. Clinical data, including manifestations, metabolites, molecular diagnosis, treatment and outcome, were summarized and analyzed. RESULTS: The age of onset ranged from 2 to 32.8 years old (median age 8.6 years, mean age 9.4 years). The time between first symptoms and diagnosis ranged from a few days to 20 years (median time 2 months, mean time 20.7 months). Neuropsychiatric symptoms were presented as first symptoms in 68.2% of cases, which were observed frequently in schoolchildren or adolescents. Renal involvement and cardiovascular disease were observed in 20% and 8.2% of cases, respectively, which occurred with the highest prevalence in preschool children. Besides the initial symptoms, the disease progressed in most patients and cognitive decline became the most frequent symptom overall. The levels of propionylcarnitine, propionylcarnitine / acetylcarnitine ratio, methylmalonic acid, methylcitric acid and homocysteine, were decreased remarkably after treatment (P<0.001). Twenty-four different mutations of MMACHC were identified in 78 patients, two of which were novel. The c.482G>A variant was the most frequent mutated allele in this cohort (25%). Except for 16 patients who recovered completely, the remaining patients were still left with varying degrees of sequelae in a long-term follow-up. The available data from 76 cases were analyzed by univariate analysis and multivariate logistic regression analysis, and the results showed that the time from onset to diagnosis (OR = 1.025, P = 0. 024) was independent risk factors for poor outcomes. CONCLUSIONS: The diagnosis of late-onset cblC defect is often delayed due to poor awareness of its various and nonspecific symptoms, thus having an adverse effect on the prognosis. It should be considered in patients with unexplained neuropsychiatric and other conditions such as renal involvement, cardiovascular diseases or even multiple organ damage. The c.482G>A variant shows the highest frequency in these patients. Prompt treatment appears to be beneficial.

An X-ray activatable gold nanorod encapsulated liposome delivery system for mitochondria-targeted photodynamic therapy (PDT).

In this work, we developed a mitochondria-targeted nanomaterial for neoadjuvant X-ray-triggered photodynamic therapy of rectal cancer. Herein, we designed a biodegradable liposome incorporating a photosensitizer, verteporfin, to generate X-ray-induced reactive oxygen species, gold nanorods as radiation enhancers, and triphenylphosphonium as the mitochondrial targeting moiety. The average size of the nanocarrier was about 150 nm. Due to the synergetic effect between X-ray and a combination of verteporfin and gold nanorods, as well as precise site-targeted TPP-modified liposomal nanocarriers, our nanoconjugates generated sufficient cytotoxic singlet oxygen within the mitochondria under X-ray irradiation, triggering the loss of membrane potential and mitochondria-related apoptosis of cancer cells.

Resource utilization of medical waste under COVID-19: Waste mask used as crude oil fluidity improver.

The disposal of medical waste has become an increasing environmental issue since the COVID-19 epidemic outbreaks. Conventional disposal methods have produced waste of fossil resources and environmental problems. In this study, the waste medical mask-derived materials were tested as viscosity reducer and pour point depressant to evaluate the possibility of being used as crude oil fluidity improver. The results show that the materials derived from the three parts of the waste medical mask can reduce the viscosity and pour point of each crude oil samples from different oilfields in China. The middle layer of the medical mask (PP-2) displays the highest efficiency, and the viscosity reduction rate and maximum pour point reduction reaches 81% and 8.3 °C at 500 ppm, respectively. A probable mechanism of improving rheological properties of the crude oil samples by the medical mask-derived materials was further proposed after the differential scanning calorimetry (DSC) analysis and the wax crystal morphology analysis. We hope this work could provide a way to solve the current environmental issues under COVID-19.

Clinical, genetic profile and therapy evaluation of 55 children and 5 adults with sitosterolemia.

BACKGROUND: Sitosterolemia is a rare autosomal recessive disease characterized by phytosterol accumulation in the blood and tissues. However, the detailed clinical and genetic spectra are lacking. OBJECTIVE: To describe and compare the clinical, biochemical, genetic, therapeutic, and follow-up characteristics of 55 pediatric and five adult sitosterolemia patients. METHODS: Clinical, genetic and therapeutic data from 60 patients at Xinhua Hospital from January 2016 to June 2021 were retrospectively collected. RESULTS: Pediatric patients' manifestations included xanthomas(93%), hematological disorders(30%), arthralgia(24%), splenomegaly(11%), atherosclerosis(10%). Adult patients had symptoms such as atherosclerosis(5/5), xanthomas(4/5), hematological disorders(3/5), arthralgia(3/5), splenomegaly(3/5). Elevated total cholesterol(TC) and low-density lipoprotein cholesterol(LDL-C) were observed in 96% patients (pediatric 98%, adult 3/4), and phytosterol levels in 100% patients. The age of onset was also negatively correlated with blood TC (P < 0.0001, r = -0.5548) and LDL-C (P = 0.0001, r = -0.4859) levels. Targeted treatments resulted in symptomatic remission(pediatric 96%, adult 4/5), and significantly decreased lipid and phytosterol levels(all P<0.05). In the dietary-therapy cohort(n=34), blood lipid levels decreased(all P<0.05). In the 13 pediatric patients from the dietary-therapy cohort who switched from dietary to combination therapy with ezetimibe, dietary therapy decreased TC and LDL-C levels by 54% and 52%, and ezetimibe further decreased them by 18% and 20%, respectively. Further, we identified 15 novel ABCG5/ABCG8 variants. CONCLUSIONS: This study expands the clinical and genetic spectra of sitosterolemia. The low-phytosterol diet is the cornerstone of sitosterolemia treatment. Ezetimibe can further decrease blood lipid levels and increase daily dietary phytosterol tolerance.

An intronic variant disrupts mRNA splicing and causes FGFR3-related skeletal dysplasia.

OBJECTIVES: Achondroplasia and hypochondroplasia are the most common forms of disproportionate short stature, of which the vast majority of cases can be attributed to the hotspot missense mutations in the gene FGFR3. Here we presented cases with a novel cryptic splicing variant of FGFR3 gene and aimed to interrogate the variant pathogenicity. CASE PRESENTAITON: In whole exome sequencing of two patients with hypochondroplasia-like features, a de novo intronic variant c.1075 + 95C>G was identified, predicted to alter mRNA splicing. Minigene assay showed that this intronic variant caused retention of a 90-nucleotide segment of intron 8 in mRNA, resulting in a 30-amino acid insertion at the extracellular domain of the protein. This is the first likely pathogenic splicing variant identified in the FGFR3 gene and was detected in one additional patient among 26 genetically unresolved patients. CONCLUSTIONS: Our results strongly suggest that c.1075 + 95C>G is a recurrent mutation and should be included in genetic testing of FGFR3 especially for those patients with equivocal clinical findings and no exonic mutations identified.

Value of amniotic fluid homocysteine assay in prenatal diagnosis of combined methylmalonic acidemia and homocystinuria, cobalamin C type.

BACKGROUND: Combined methylmalonic acidemia and homocystinuria, cobalamin C type (cblC defect) is the most common inborn error of cobalamin metabolism, and different approaches have been applied to its prenatal diagnosis. To evaluate the reliability of biochemical method for the prenatal diagnosis of cblC defect, we conducted a retrospective study of our 10-year experience at a single center. METHODS: 248 pregnancies whose probands were diagnosed as cblC defect were referred to our center for prenatal diagnosis from January 2010 to December 2019. Prenatal data of Hcy levels determined by enzymatic cycling assay, acylcarnitine analysis using liquid chromatography tandem mass spectrometry, organic acid analysis using gas chromatography mass spectrometry, and genetic analysis by direct sequencing of 248 at-risk fetuses were retrospectively reviewed. RESULTS: For 2.0 and 16.0 µmol/L levels of Hcy AF samples, the relative errors were - 2.5% and 2.8%, respectively. The respective measurement uncertainties were 13.07% and 14.20%. For the 248 at-risk fetuses, 63 fetuses were affected and 185 fetuses were unaffected. Hcy level of 13.20 (6.62-43.30) µmol/L in 63 affected fetuses was significantly higher than that in 185 unaffected fetuses of 2.70 (0.00-5.80) µmol/L, and there was no overlap between the affected and unaffected groups. The diagnostic sensitivity and specificity of Hcy were 100% and 92.05%, respectively. The positive and negative predictive values of the combination of Hcy, propionylcarnitine (C3), ratio of C3 to acetylcarnitine (C2; C3/C2), methylmalonic acid (MMA), and methylcitric acid (MCA) were both 100%. Sixteen fetuses displayed inconclusive genetic results of MMACHC variants, in which seven fetuses were determined to be affected with elevated levels of Hcy, C3, C3/C2 and MMA, and their levels were 18.50 (6.70-43.30) µmol/L, 8.53(5.02-11.91) µmol/L, 0.77 (0.52-0.97), 8.96 (6.55-40.32) mmol/mol Cr, respectively. The remaining nine fetuses were considered unaffected based on a normal amniotic fluid metabolite profile. CONCLUSIONS: Hcy appears to be another characteristic biomarker for the prenatal diagnosis of cblC defect. The combination of Hcy assay with acylcarnitine and organic acid analysis is a fast, sensitive, and reliable prenatal diagnostic biochemical approach. This approach could overcome the challenge of the lack of genetic analysis for families with at-risk cblC defect fetuses.

Chromosomal microarray analysis in fetuses with high-risk prenatal indications: A retrospective study in China.

OBJECTIVE: The present study aimed to determine the diagnostic value of prenatal chromosomal microarray analysis (CMA) for fetuses with several indications of being at high risk for various conditions. MATERIALS AND METHODS: This retrospective analysis included 1256 pregnancies that were prenatally evaluated due to high-risk indications using invasive CMA. The indications for invasive prenatal diagnosis mainly included ultrasound anomalies, high-risk for maternal serum screening (MSS), high-risk for non-invasive prenatal tests (NIPT), family history of genetic disorders or birth defects, and advanced maternal age (AMA). The rate of clinically significant genomic imbalances between the different groups was compared. RESULTS: The overall prenatal diagnostic yield was 98 (7.8%) of 1256 pregnancies. Clinically significant genomic aberrations were identified in 2 (1.5%) of 132 patients with non-structural ultrasound anomalies, 36 (12.7%) of 283 with structural ultrasound anomalies, 2 (4.5%) of 44 at high-risk for MSS, 38 (26.6%) of 143 at high-risk for NIPT, 11 (3.8%) of 288 with a family history, and 7 (2.1%) of 328 with AMA. Submicroscopic findings were identified in 29 fetuses, 19 of whom showed structural ultrasound anomalies. CONCLUSION: The diagnostic yields of CMA for pregnancies with different indications greatly varied. CMA could serve as a first-tier test for structural anomalies, especially multiple anomalies, craniofacial dysplasia, urinary defects, and cardiac dysplasia. Our results have important implications for genetic counseling.

X-ray induced photodynamic therapy (PDT) with a mitochondria-targeted liposome delivery system.

In this study, we constructed multifunctional liposomes with preferentially mitochondria-targeted feature and gold nanoparticles-assisted synergistic photodynamic therapy. We systemically investigated the in vitro X-ray triggered PDT effect of these liposomes on HCT 116 cells including the levels of singlet oxygen, mitochondrial membrane potential, cell apoptosis/necrosis and the expression of apoptosis-related proteins. The results corroborated that synchronous action of PDT and X-ray radiation enhance the generation of cytotoxic reactive oxygen species produced from the engineered liposomes, causing mitochondrial dysfunction and increasing the levels of apoptosis.

Noninvasive prenatal diagnosis of cobalamin C (cblC) deficiency through target region sequencing of cell-free DNA in maternal plasma.

OBJECTIVE: This study aimed to validate the feasibility of haplotype-based noninvasive prenatal diagnosis (NIPD) of cobalamin C (cblC) deficiency. METHOD: This method includes three steps: First, targeted sequencing was performed on 21 families affected by cblC deficiency (including the couples and probands). Second, parental haplotypes linked with the pathogenic variant were determined using the genotypes of trios. Then, the fetal haplotypes were inferred through a parental haplotype assisted hidden Markov model (HMM). The NIPD results were confirmed by using the invasive procedures. RESULTS: Twenty-one fetal genotypes were successfully inferred by NIPD including three compound heterozygotes with cblC deficiency, nine heterozygote carriers of cblC deficiency, and nine normal fetuses. The NIPD results were confirmed using the invasive procedures with 100% concordant rate. CONCLUSION: This result has shown that haplotype-based NIPD of cblC deficiency has high concordant rate and indicated potential clinical utility as a pregnancy diagnosis method for high-risk carrier couples.

Identification of RUNX2 variants associated with cleidocranial dysplasia.

BACKGROUND: Cleidocranial dysplasia (CCD) is a rare autosomal dominant disorder mainly characterized by hypoplastic or absent clavicles, delayed closure of the fontanelles, multiple dental abnormalities, and short stature. Runt-related transcription factor 2 (RUNX2) gene variants can cause CCD, but are not identified in all CCD patients. METHODS: In this study, we detected genetic variants in seven unrelated children with CCD by targeted high-throughput DNA sequencing or Sanger sequencing. RESULTS: All patients carried a RUNX2 variant, totally including three novel pathogenic variants (c.722_725delTGTT, p.Leu241Serfs*8; c.231_232delTG, Ala78Glyfs*82; c.909C > G, p.Tyr303*), three reported pathogenic variants (c.577C > T, p.Arg193*; c.574G > A, p.Gly192Arg; c.673 C > T, p.Arg225Trp), one likely pathogenic variant (c.668G > T, p.Gly223Val). The analysis of the variant source showed that all variants were de novo except the two variants (c.909C > G, p.Tyr303*; c.668G > T, p.Gly223Val) inherited from the patient's father and mother with CCD respectively. Further bioinformatics analysis indicated that these variants could influence the structure of RUNX2 protein by changing the number of H-bonds or amino acids. The experimental result showed that the Gly223Val mutation made RUNX2 protein unable to quantitatively accumulate in the nucleus. CONCLUSIONS: The present study expands the pathogenic variant spectrum of RUNX2 gene, which will contribute to the diagnosis of CCD and better genetic counseling in the future.

[Retrospective analysis on clinical data and genetic variations of patients with beta-ketothiolase deficiency].

OBJECTIVE: To summarize the clinical, biochemical and molecular characteristics of 8 patients with beta-ketothiolase deficiency (BKD). METHODS: Clinical characteristics, biochemical markers detected by tandem mass spectrometry (MS-MS) and gas chromatography-mass spectrometry (GC-MS), and variations of ACAT1 gene of the 8 patients were reviewed. RESULTS: Three patients were diagnosed by newborn screening and were asymptomatic. Five patients showed dyspnea and metabolic acidosis through high risk screening. Blood methylcrotonyl carnitine (C5:1) were 0.43 (0.20-0.89) µmol/L and 3-hydroxyisovaleryl carnitine(C5-OH) were 1.37 (0.98-3.40) µmol/L. Both were significantly higher than those of healthy controls (P<0.01). Urinary 2-methyl-3-hydroxybutyric acid was 56.04 (7.69-182.20) and methylcrotonyl glycine was 42.83 (9.20-127.01), both were higher than normal levels. In 5 patients urinary 2-methyl-3-hydroxybutyric acid level was remarkably decreased (P<0.05) after treatment. Analysis of ACAT1 gene mutation was performed in six families. Missense variations were detected in 78.6% of the cases. 42.8% of the 7 BKD patients have carried c.1124A>G (p.N375S) variant, which accounted for 28.6% of all 14 mutant alleles. Four novel variants, namely c.229delG (p.E77KfsTer10), c.373G>T (p.V125F), c.419T>G (p.L140R) and c.72+1G>A, were discovered. Pathogenicity assessment of two highly conservative missense variants (p.V125F) and (p.L140R) were 0.994 and 1.0 (Scores obtained from PolyPhen2), and PROVEAN scores were -4.652 and -5.399, respectively. c.72+1g>a was suspected (by Human Splicing Finder) to alter the wild type donor motif and most probably affect the splicing. CONCLUSION: Clinicians should consider MS/MS and GC/MS testing for those with unexplained neurological symptoms and metabolic acidosis in order to attain early diagnosis of BKD. Genetic testing should be used to confirm the diagnosis.

Targeted/exome sequencing identified mutations in ten Chinese patients diagnosed with Noonan syndrome and related disorders.

BACKGROUND: Noonan syndrome (NS) and Noonan syndrome with multiple lentigines (NSML) are autosomal dominant developmental disorders. NS and NSML are caused by abnormalities in genes that encode proteins related to the RAS-MAPK pathway, including PTPN11, RAF1, BRAF, and MAP2K. In this study, we diagnosed ten NS or NSML patients via targeted sequencing or whole exome sequencing (TS/WES). METHODS: TS/WES was performed to identify mutations in ten Chinese patients who exhibited the following manifestations: potential facial dysmorphisms, short stature, congenital heart defects, and developmental delay. Sanger sequencing was used to confirm the suspected pathological variants in the patients and their family members. RESULTS: TS/WES revealed three mutations in the PTPN11 gene, three mutations in RAF1 gene, and four mutations in BRAF gene in the NS and NSML patients who were previously diagnosed based on the abovementioned clinical features. All the identified mutations were determined to be de novo mutations. However, two patients who carried the same mutation in the RAF1 gene presented different clinical features. One patient with multiple lentigines was diagnosed with NSML, while the other patient without lentigines was diagnosed with NS. In addition, a patient who carried a hotspot mutation in the BRAF gene was diagnosed with NS instead of cardiofaciocutaneous syndrome (CFCS). CONCLUSIONS: TS/WES has emerged as a useful tool for definitive diagnosis and accurate genetic counseling of atypical cases. In this study, we analyzed ten Chinese patients diagnosed with NS and related disorders and identified their correspondingPTPN11, RAF1, and BRAF mutations. Among the target genes, BRAF showed the same degree of correlation with NS incidence as that of PTPN11 or RAF1.

Molecular defects identified by whole exome sequencing in a child with atypical mucopolysaccharidosis IIIB.

BACKGROUND: Mucopolysaccharidosis IIIB (MPS IIIB) is a genetic disease characterized by mutations in the NAGLU gene, deficiency of α-N-acetylglucosaminidase, multiple congenital malformations and an increased susceptibility to malignancy. Because of the slow progressive nature of this disease and its atypical symptoms, the misdiagnosis of MPS IIIB is not rare in clinical practice. This misdiagnosis could be avoided by using next-generation sequencing (NGS) techniques, which have been shown to have superior performance for detecting mutations underlying rare inherited disorders in previous studies. CASE PRESENTATION: Whole exome sequencing (WES) was conducted and the putative pathogenic variants were validated by Sanger sequencing. The activity of MPS IIIB related enzyme in the patient's blood serum was assayed. A heterozygous, non-synonymous mutation (c.1562C>T, p.P521L) as well as a novel mutation (c.1705C>A, p.Q569K) were found in the NAGLU gene of the patient. The two mutations were validated by Sanger sequencing. Our data showed that this patient's c.1562C>T, p.P521L mutation in the NAGLU gene was inherited from his father and c.1705C>A, p.Q569K was from his mother. The diagnosis was further confirmed by an enzymatic activity assay after patient recall and follow-up. CONCLUSIONS: Our results describe an atypical form of MPS IIIB and illustrate the diagnostic potential of targeted WES in Mendelian disease with unknown etiology. WES could become a powerful tool for molecular diagnosis of MPS IIIB in clinical setting.

Further delineation of the phenotype of truncating KMT2A mutations: The extended Wiedemann-Steiner syndrome.

KMT2A mutations cause Wiedemann-Steiner syndrome (WDSTS), which is characterized by hypertrichosis cubiti, short stature, and distinct facial features in general. Here, we report two Chinese boys with novel nonsense KMT2A mutations. Most of their phenotypes are concordant with WDSTS. They, however, lack the key WDSTS feature-hypertrichosis cubiti. Additionally, their transverse palmar creases are absent. We further summarized the genotypes and phenotypes of the KMT2A mutation carriers. The consensus phenotypes include postnatal growth retardation, developmental delay, short stature, and intellectual disability. The common facial features include thick eyebrows, long eyelashes, downslanting, and narrow palpebral fissures, wide nasal bridge, and broad nasal tip. They have generalized hypertrichosis. A hairy back can be observed as frequently as hairy elbows in patients with KMT2A mutations. Absent palmar proximal transverse creases are only observed in these two Chinese boys. This might be due to the difference in ethnic background. Thus far, all mutations in KMT2A are located before the FYRC domain. They would truncate KMT2A mRNA transcripts. Haploinsufficiency of the histone methyltransferase activity would therefore influence transcriptional regulation. © 2016 Wiley Periodicals, Inc.

Demographic characteristics and distribution of lysosomal storage disorder subtypes in Eastern China.

Lysosomal storage disorders (LSDs) are a group of >50 different types of inherited metabolic disorders that result from defects in the lysosome. The aim of this study was to investigate the distribution and demographic characteristics of the different subtypes of LSDs in Eastern China. From 2006 to 2012, 376 out of 1331 clinically suspected patients were diagnosed with 17 different subtypes of LSDs at our hospital. Mucopolysaccharidoses (MPS) were the most common group of LSDs (50.5%), followed by sphingolipidoses (25.4%) and Pompe disease (19.8%). Mucolipidosis type II/III accounted for the remaining 4% of diagnosed LSDs. MPS II was the most common form of MPS, comprising 47.4% of all MPS cases diagnosed, followed by MPS IVA (26.8%) and MPS I (16.3%). Gaucher disease and Niemann-Pick disease type A/B were the two most common forms of sphingolipidoses. There was a large variation in the time between disease onset and eventual diagnosis, from 0.3 years in infantile-onset Pompe disease to 30 years in Fabry disease, highlighting timely and accurate diagnosis of LSDs as the main challenge in China.

SIDT2 is involved in the NAADP-mediated release of calcium from insulin secretory granules.

The Sidt2 global knockout mouse (Sidt2(-/-)) has impaired insulin secretion. The aim of this study was to assess the role of SIDT2 protein in glucose-induced insulin secretion in primary cultured mouse ß-cells. The major metabolic and electrophysiological steps of glucose-induced insulin secretion of primary cultured ß-cells from Sidt2(-/-) mice were investigated. The ß-cells from Sidt2(-/-) mice had normal NAD(P)H responses and KATP and KV currents. However, they exhibited a lower [Ca(2+)]i peak height when stimulated with 20mM glucose compared with those from WT mice. Furthermore, it took a longer time for the [Ca(2+)]i of ß-cell from Sidt2(-/-) mice to reach the peak. Pretreatment with ryanodine or 2-aminoethoxydiphenyl borate (2-APB) did not change [Ca(2+)]i the response pattern to glucose in Sidt2(-/-) cells. Extraordinarily, pretreatment with bafilomycin A1(Baf-A1) led to a comparable [Ca(2+)]i increase pattern between these two groups, suggesting that calcium traffic from the intracellular acidic compartment is defective in Sidt2(-/-) ß-cells. Bath-mediated application of 50nM nicotinic acid adenine dinucleotide phosphate (NAADP) normalized the [Ca(2+)]i response of Sidt2(-/-) ß-cells. Finally, glucose-induced CD38 expression increased to a comparable level between Sidt2(-/-) and WT islets, suggesting that Sidt2(-/-) islets generated NAADP normally. We conclude that Sidt2 is involved in NAADP-mediated release of calcium from insulin secretory granules and thus regulates insulin secretion.

Eight novel mutations in the ABCD1 gene and clinical characteristics of 25 Chinese patients with X-linked adrenoleukodystrophy.

BACKGROUND: X-linked adrenoleukodystrophy (X-ALD) is a fatal neurodegenerative disease caused by mutations in the adenosine triphosphate-binding cassette D1 (ABCD1) gene. This study aimed to retrospectively investigate the clinical characteristics of 25 patients with X-ALD including members of large pedigrees, to analyze ABCD1 gene mutations, the effect of gene novel variants on ALD protein (ALDP) structure and function, and to expand gene mutation spectrum of Chinese patients. METHODS: Twenty-five male patients diagnosed with X-ALD were enrolled in this study. The clinical characteristics of the patients were retrospectively summarized by reviewing medical records or telephone consultation. ABCD1 gene mutations were analyzed. The pathogenicity of novel missense variants was analyzed using cobalt constraint-based multiple protein alignment tool, polymorphism phenotyping, sorting intolerant from tolerant, Align-Grantham variation and Grantham deviation, and Swiss-Program Database Viewer 4.04 software, respectively. RESULTS: Childhood cerebral form ALD (CCALD) is the most common phenotype (64%) in the 25 patients with X-ALD. The progressive deterioration of neurological and cognitive functions is the main clinical feature. The demyelination of the brain white matter and elevated plasma very long chain fatty acids (VLCFAs) were found in all patients. Different phenotypes were also presented within family members of the patients. Twenty-two different mutations including 8 novel mutations in the ABCD1 gene were identified in the 25 patients. Of the mutations, 63.6% were missense mutations and 34.8% located in exon 1. The amino acid residues of three novel missense mutations in eight species were highly conserved, and were predicted to be "probably" damaging to ALDP function. The other five novel mutations were splice, nonsense, deletion or duplication mutations. CONCLUSIONS: CCALD is the most common phenotype (64%) in our patients with X-ALD. Eight novel mutations in the ABCD1 gene identified are disease-causing mutations. Brain magnetic resonance imaging and plasma VLCFA determination should be performed for the patients who present with progressive deterioration of neurological development.