Diagnostic yield of additional exome sequencing after the detection of long continuous stretches of homozygosity (LCSH) in SNP arrays

Long continuous stretches of homozygosity (LCSH) are associated with risk of recessive disorders. Though LCSH can be detected by SNP microarrays, additional testing is necessary to clarify the clinical significance. This study is to assess the yield of additional exome sequencing (ES) after LCSH detection and inform the likelihood of eventual diagnosis. In 2226 patients referred to SNP microarrays, 35 patients met the criteria of indicative LCSH. These patients were recruited and went through additional ES. The diagnostic yield was analyzed, and the LCSH pattern was compared between eventually diagnosed cases and those undiagnosed. The results showed additional ES attained a diagnostic yield of 31.4% (11/35), but only one-third of the yield (11.4%, 4/35) was relevant to LCSH. In contrast, two-thirds of the diagnostic variants (20%, 7/35) were de novo or dominantly inherited, irrelevant to the original LCSH finding. No particular LCSH pattern, including the chromosomal coverage or LCSH size, was found to associate with the diagnostic outcome. We concluded that additional ES after LCSH detection could reveal diagnostic variants, but it is strongly recommended to consider all possible inheritance mode, as the diagnostic variants may be irrelevant to the original LCSH finding.

Biochemical and genetic approaches to the prenatal diagnosis of propionic acidemia in 78 pregnancies

Background

Propionic acidemia (PA) is a serious metabolic disorder, and different approaches have been applied to its prenatal diagnosis. To evaluate the reliability and validity of a biochemical strategy in the prenatal diagnosis of PA, we conducted a retrospective study of our 11-year experiences at a single center.

Methods

We accumulated data from 78 pregnancies from 58 families referred to our center and provided prenatal diagnosis by directed genetic analysis and/or metabolite measurement using tandem mass spectrometry (MS/MS) and gas chromatography/mass spectrometry (GC/MS) of amniotic fluid (AF) samples.

Results

Sixty-five unaffected fetuses (83.33%) and 13 affected fetuses (16.67%) were confirmed in our study. The characteristic metabolites including propionylcarnitine (C3) level, C3/acetylcarnitine (C2) ratio and 2-methylcitric acid (2MCA) level in unaffected and affected groups showed significant differences (P < 0.0001), while the level of 3-hydroxypropionic acid (3HPA) showed no significant difference between the two groups (P > 0.05).Of the 78 pregnancies, 24 fetuses were found to have either one causative pathogenic variant or were without genetic information in the proband. Three of these fetuses had elevated AF levels of C3, C3/C2 ratio, and 2MCA and, thus, were determined to be affected, while the remaining fetuses were determined to be unaffected based on a normal AF metabolite profile. Our genetic and biochemical results were highly consistent with postnatal follow-up results on all unaffected fetuses.

Conclusions

We conclude that a biochemical approach can serve as a fast and convenient prenatal diagnostic method for pregnancies at an increased risk for PA, which could be used in conjunction with genetic testing for precise prenatal diagnosis of this disorder. In our analysis, the characteristic metabolites C3 level, C3/C2 ratio, and 2MCA level in AF supernatant were dependable biochemical markers for diagnosis, of which the C3/C2 ratio appears to be the most reliable biochemical marker for the prenatal diagnosis of PA.

[Exploring the clinical genetic characteristics and height for age growth curve of 210 patients with achondroplasia in China]

Objective: To summarize the clinical manifestation and genetic characteristics of Chinese patients with achondroplasia (ACH) which is caused by pathogenic variants fibroblast growth factor receptor 3 (FGFR3) gene and establish the reference value of height centiles and height for age growth curve of patients for a more practical, simple and useful growth evaluation tool in China. Methods: Through a nationwide cross-sectional survey in China from July 2019 to January 2020 designed by Department of Pediatric Endocrinology and Genetics, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, 210 subjects (110 boys, 100 girls), who harbored the pathogenic variant of FGFR3 gene and were diagnosed with achondroplasia, were recruited. The clinical and genetic data of enrolled subjects were collected and analyzed to explore the clinical genetic characteristics of Chinese ACH patients. Furthermore, according to the data of height (body length under 2 years old) of boy and girl subjects aged 0-12 years, centiles and height for age growth curve of achondroplasia were calculated and established by LMS method respectively. Results: The characteristic clinical manifestations of 210 Chinese patients (0-14 years old) were disproportionate short stature (206/210, 98.1%), macrocephaly and characteristic facial features (205/210, 97.6%), trident configuration of the hands (191/210, 90.9%), limbs deformity (156/210, 74.3%), together with normal intelligence. Up to 81.9% (172/210) of patients have different complications, and the kyphosis (121/210, 57.6%) and narrow thoracic (79/210, 37.6%) are common complications. Besides, up to 98.6% (207/210) of patients harbored hotspot variants of FGFR3 gene which cause G380R amino acid substitutions. It is notable that the growth pattern of boy and girl patients (0-12 years old) is obviously different from the normal children (t=9.849, 9.596, P<0.01) respectively. The height different between ACH patients and normal children gradually widened with age. The average height of the boy (49.2 cm) and girl patients(48.4 cm) of achondroplasia at birth was -1.22 s and -2 s, however, at the age of twelve, the average height of the boy(113.7 cm) and girl patients(112.4 cm) of achondroplasia was -5.23 s and -6.15 s compared to currently standard reference height for age growth curve of normal children in China, respectively. Conclusions: The results of our study demonstrated that in China disproportionate short stature, macrocephaly and characteristic facial features were typical manifestations of ACH patients, and that up to 98.6% of patients harbored hotspot variants of FGFR3 gene. In addition, the reference value of height centiles and height for age growth curve of ACH patients we establish will be a valuable tool for evaluating the growth pattern, monitoring factors affecting growth, estimating ultimate height, and assessing the curative effect of growth-promoting treatments in Chinese patients with achondroplasia.

A pilot study of expanded newborn screening for 573 genes related to severe inherited disorders in China: results from 1,127 newborns

Background

Newborn screening (NBS) in China is mainly aimed at detecting biochemical levels of metabolites in the blood, which may generate false-positive/negative results. Current biochemical NBS includes tandem mass spectrometry (MS/MS) screening for metabolites as well as phenylalanine (Phe), thyroid-stimulating hormone (TSH), 17-α-hydroxyprogesterone (17-OHP), and glucose-6-phosphate dehydrogenase (G6PD) test. This study intended to explore whether next-generation sequencing (NGS) for dried blood spots combining with biochemical screening could improve the current screening efficiency and to investigate the carrier frequencies of mutations in causative genes related to amino acid metabolism, organic acid metabolism, and fatty acid oxidation in this cohort.

Methods

We designed a panel of 573 genes related to severe inherited disorders and performed NGS in 1,127 individuals who had undergone biochemical NBS. The NGS screening results of neonates were used to compare with the biochemical results.

Results

NGS screening results revealed that all the four newborns with abnormal G6PD values carried hemizygous G6PD mutations, which were consistent with the decreased G6PD enzymatic activity. The NGS results revealed an individual with compound heterozygous mutations of SLC22A5, who was biochemically negative in 2016. The MS/MS screening results in 2019 showed free carnitine deficiency, which was consistent with the genetic findings. The top five genes with the highest carrier frequencies of mutations in these newborns were PAH (1:56, 1.79%), ETFDH (1:81, 1.23%), MMACHC (1:87, 1.15%), SLC25A13 (1:102, 0.98%), and GCDH (1:125, 0.80%).

Conclusions

Our study highlighted that combining NGS screening with biochemical screening could improve the current NBS efficiency. This is the first study to investigate carrier frequencies of mutations in 77 genes causing inherited metabolic diseases (IMDs) in China.

Whole Genome Low-Coverage Sequencing Concurrently Detecting Copy Number Variations and Their Underlying Complex Chromosomal Rearrangements by Systematic Breakpoint Mapping in Intellectual Deficiency/Developmental Delay Patients

Simple copy number variations (CNVs) detected by chromosomal microarray (CMA) can result from complex structural changes. Therefore, it is necessary to characterize potential structural changes that cause pathogenic CNVs. We applied whole-genome low-coverage sequencing (WGLCS) to concurrently detect pathogenic CNVs and their associated chromosomal rearrangements in 15 patients. All the patients had an average of 2–3 pathogenic CNVs involving 1–2 chromosomes. WGLCS identified all the 34 pathogenic CNVs found by microarray. By identifying chimeric read pairs, WGLCS mapped 70 breakpoints in these patients, of which 47 were finely mapped at the nucleotide level and confirmed by subsequent PCR amplification and Sanger sequencing of the junction fragments. In 15 patients, structural rearrangements were defined at molecular level in 13 patients. In 13 patients, WGLCS reveal no additional results in two patients. In another 11 patients, WGLCS revealed new breakpoints or finely mapped the genes disrupted by breakpoints or 1–6 bp microhomology and/or short insertion (4–70 bp) in the breakpoints junctions. However, structural changes in the other two patients still remained unclear after WGLCS was performed. The structural alteration identified in the 13 patients could be divided into the following categories: (1) interstitial inverted duplication with concomitant terminal deletion (inv dup del) (P1,P4,P9,P11); (2) the product of pericentric inversion (P5); (3) ring chromosome (P8); (4) interstitial duplication and/or triplication (P6, P7); and (5) +der(22)t(11;22) (P2,P15); (6) complex structural rearrangements (P3,P12,P14). WGLCS displayed the ability to discover CNVs and define breakpoints and its disrupted genes and its surrounding sequences in one experiment at base-pair-resolution, which help us to learn more about the mechanisms of formation of observed genomic rearrangements, and in which DNA replicative/repair mechanism might contribute to the formation of complex rearrangements in 11 patients. Clear karyotype at molecular level could help provide an accurate evaluation of recurrent risk and guide prenatal diagnosis or reproductive planning.

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.

Electronic structural properties of amino/hydroxyl functionalized imidazolium-based bromide ionic liquids

Electronic structural properties of the three different imidazolium-based ionic liquids, namely, 1-butyl-3-methyl imidazolium bromide (C4mimBr), 1-(4-hydroxybutyl)-3-methylimidazolium bromide (C4OHmimBr), and 1-(4-aminobutyl)-3-methylimidazolium bromide (C4NH2mimBr), were investigated with density functional theory at the B3LYP/6-311++G(d,p) level. The conformations of the mentioned cations were fully studied first using CONFLEX 8.A program. The quantum theory of atoms in molecules was used to investigate the nature of intramolecular interactions. The counterpoise-corrected ion pairs binding energies were obtained at the same level of theory. Natural bond orbital analyses show that the largest intra-molecular interaction comes from the orbital overlap between n(N1) and π* (N4–C5) in the mentioned compounds. The energy levels of frontier molecular orbitals (FMOs) are displayed. The global quantum chemical descriptors are also calculated based on the energy values of FMOs.

Prenatal Diagnosis of Glutaric Acidemia I Based on Amniotic Fluid Samples in 42 Families Using Genetic and Biochemical Approaches

Direct mutation analysis is the major method for glutaric acidemia I (GA-I) prenatal diagnosis, while systemic application of a biochemical strategy is rare. We describe our experiences with metabolite measurement together with mutation analysis in GA-I prenatal diagnosis at a single center over 10 years. The data of genetic analysis and metabolite measurement using gas chromatography/mass spectrometry(GC/MS) and tandem mass spectrometry(MS/MS) in amniotic fluid samples of 44 fetuses from 42 GA-I families referred to our center from 2009 to 2019 were retrospectively analyzed. Among these 44 fetuses, genetic and biochemical results were both available in 39 fetuses. Of these, 6 fetuses were judged as affected and 33 fetuses as unaffected by mutation analysis. The levels of glutarylcarnitine (C5DC), C5DC/octanoylcarnitine (C8), and glutaric acid in the supernatant of amniotic fluid from affected fetuses were significantly higher than those in unaffected fetuses [1.73μmol/L (0.89–4.19) vs. 0.16μmol/L (0.06–0.37), 26.26 (12.4–55.55) vs. 2.23 (1.04–8.44), and 103.94 mmol/mol creatinine (30.37–148.31) vs. 1.01mmol/mol creatinine (0–9.81), respectively; all P < 0.0001]. Among all families, two were found to have one causative mutation in the proband, in four pregnancies from these two families, three fetuses were judged as “unaffected” and one was judged as “affected” according to metabolites results. Postnatal follow-up showed a normal phenotype in all unaffected fetuses judged by mutation or metabolite analysis. C5DC, C5DC/C8, and glutaric acid levels in the supernatant of amniotic fluid showed significant differences and no overlap between the affected and unaffected fetuses. Biochemical strategy could be implemented as a quick and convenient method for the prenatal diagnosis of GA-I.

Novel PYGL mutations in Chinese children leading to glycogen storage disease type VI: two case reports

Background

PYGL mutations can cause liver phosphorylase deficiency, resulting in a glycogenolysis disorder, namely, glycogen storage disease (GSD) VI. The disease is rarely reported in the Chinese population. GSD VI is mainly characterized in untreated children by hepatomegaly, growth retardation and elevated liver transaminases.

Case presentation

In this study, we report two GSD VI patients with growth retardation and abnormal liver function. There was no obvious hepatomegaly for one of them. Whole exome sequencing (WES) combined with copy number variation analysis was performed. We found a novel homozygous gross deletion, c.1621-258_2178-23del, including exons 14–17 of PYGL in patient 1. The exons 14–17 deletion of PYGL resulted in an in-frame deletion of 186 amino acids. Compound heterozygous mutations of PYGL were identified in patient 2, including a novel missense mutation c.1832C > T/p.A611V and a recurrent nonsense mutation c.280C > T/p.R94X. After treatment with uncooked cornstarch (UCS) 8 months for patient 1 and 13 months for patient 2, the liver transaminases of both patients decreased to a normal range and their stature was improved. However, patient 1 still showed mild hypertriglyceridemia.

Conclusions

We describe two GSD VI patients and expand the spectrum of PYGL mutations. Patient 1 in this study is the first GSD VI case that showed increased transaminases without obvious hepatomegaly due to a novel homozygous gross deletion of PYGL identified through WES.

Study on the Assembly Structure Variation of Cetyltrimethylammonium Bromide on the Surface of Gold Nanoparticles

In this work, the self-assembly behavior of cetyltrimethylammonium bromide (CTAB) on the surface of citrate-capped gold nanoparticles (AuNPs) in solution has been studied by UV-vis absorption spectroscopy, fluorescence probe techniques, ζ potentiometric methods, transmission electron microscopy, etc. The UV-vis spectra show that the color with the increase of CTAB for the mixture containing CTAB and a given amount of AuNPs changes from red to blue and then to red. The absolute value of ζ potential corresponding to this color change decreases initially and then increases. Specially, the reversible color change, from red to blue and then to red, could be observed only in the case of a gradual addition of a AuNP solution to a CTAB solution; however, this reversible change is not suitable for the mixture formed in a reverse order of mixing. The results from pyrene used as the fluorescence probe indicate that the features in the fluorescence spectrum (including fluorescence quenching, I ₁/I ₃, and the excimer) well correspond to those from the UV-vis spectrum mentioned above. Based on the experimental results, the mechanism of the assembly structure variation of CTAB on the surface of negatively charged AuNPs was proposed. For a given amount of AuNPs, the assembly structure of CTAB on the surface of AuNPs undergoes the transformation from a monolayer to a bilayer with the increase of CTAB. In the case of the concentration of CTAB far beyond its critical micelle concentration (CMC) and the higher ratio of CTAB and AuNPs, there is a possibility of the formation of an extra micellar structure only after the formation of a double-layer structure.

[Analysis of 12 cases with methylmalonicacidemia cblA type]

OBJECTIVE

To explore the clinical feature, genetic variant and clinical outcome of patients with cblA-type methylmalonic acidemia (MMA).

METHODS

Clinical manifestations, therapeutic schedule and prognosis of 12 patients with cblA type MMA were analyzed. MMAA gene variants were analyzed for all patients and their parents.

RESULTS

Vomiting, dyspnea and drowsiness were the major clinical features of cblA-type MMA. Eleven patients were vitamin B12-responsive. After treatment, the blood level of propionylcarnitine, ratio of propionylcarnitine/acetylcarnitine, urine level of methylmalonic acid and methylcitric acid have decreased significantly (P< 0.05). Follow-up study showed that 8 patients (66.7%) had normal development, while the rest (33.3%) remained to have various level of mental or movement delay. Fourteen MMAA gene variants were detected, with c.365T>C (p.L122P) being the most common (29.2%). Six novel variants, including c.54delA (p.A19Hfs*43), c.275G>A (p.G92V), c.456delT (p.G153Vfs*8), c.667dupA (p.T223Nfs*4), c.1114C>T (p.Q372X) and c.1137_1138delCA (p.F379Lfs*27) were found.

CONCLUSION

The main clinical manifestations of patients with cblA-type of MMA include vomiting, dyspnea and drowsiness. Most patients are vitamin B12-responsive. c.365T>C is a potential hot spot variant of MMAA gene in China.

De Novo ARID1B mutations cause growth delay associated with aberrant Wnt/β-catenin signaling

Haploinsufficiency of ARID1B (AT-rich interaction domain 1B) has been involved in autism spectrum disorder, nonsyndromic and syndromic intellectual disability, and corpus callosum agenesis. Growth impairment is a major clinical feature caused by ARID1B mutations; however, the mechanistic link has not been elucidated. Here, we confirm that growth delay is a common characteristic of patients with ARID1B mutations, which may be associated with dysregulation of the Wnt/β-catenin signaling pathway. An analysis of patients harboring pathogenic variants of ARID1B revealed that nearly half had short stature and nearly all had below-average height. Moreover, the percentage of patients with short stature increased with age. Knockdown of arid1b in zebrafish embryos markedly reduced body length and perturbed the expression of both chondrogenic and osteogenic genes including sox9a, col2a1a, runx2b, and col10a1. Knockout of Arid1b in chondrogenic ATDC5 cells inhibited chondrocyte proliferation and differentiation. Finally, Wnt/β-catenin signaling was perturbed in Arid1b-depleted zebrafish embryos and Arid1b knockout ATDC5 cells. These data indicate that ARID1B modulates bone growth possibly via regulation of the Wnt/β-catenin pathway, and may be an appropriate target for gene therapy in disorders of growth and development.

Aromatic L-amino acid decarboxylase deficiency in 17 Mainland China patients: Clinical phenotype, molecular spectrum, and therapy overview

Background

Aromatic L‐amino acid decarboxylase deficiency (AADCD) is a rare, autosomal recessive inherited disorder which is characterized by neurological and vegetative symptoms. To date, only 130 patients with AADCD have been reported worldwide.

Methods

We demonstrated 14 previously undescribed patients together with three reportedly patients in Mainland China. Full clinical information was collected, and disease‐causing variants in the DDC gene were detected.

Results

The common clinical manifestation of patients, including intermittent oculogyric crises, retarded movement development, and autonomic symptoms. Notably, a patient showed bone‐density loss which have not been reported and two mildly phenotype patients improved psychomotor function after being prescribed medication. The most common genotype of Mainland Chinese AADCD is the splice‐site variant (IVS6+4A> T; c.714+4A> T), which accounts for 58.8%, followed by c.1234C>T variant. Three novel compound heterozygous variants, c. 565G>T, c.170T>C, and c.1021+1G>A, were firstly reported. It is important to recognize the milder phenotypes of the disease as these patients might respond well to therapy. Besides, we discovered that patients may presented with milder if found to be compound heterozygote or homozygote for one of the following variants c.478C>G, c.853C>T, c.1123C>T, c.387G>A, and c.665T>C.

Discussion

The clinical data of the cohort of 17 patients in Mainland China broaden the clinical, molecular, and treatment spectrum of aromatic L‐amino acid decarboxylase deficiency.

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.

A Novel Nonsense Mutation of PHF6 in a Female with Extended Phenotypes of Borjeson-Forssman-Lehmann Syndrome

Borjeson-Forssman-Lehmann syndrome (BFLS) is a rare X-linked disease caused by PHF6 mutations. Classic BFLS has been associated with intellectual disability (ID), developmental delay (DD), obesity, epilepsy, typical facial features and anomalies of fingers and toes. Endocrinological phenotypes and outcome of treatment in this condition remain to be delineated. Here we report a patient who exhibited complete growth hormone deficiency who responded to hormonal treatment but with adverse effects. Horseshoe kidney was present in this patient, which is also atypical in BFLS. A heterozygous nonsense mutation c.673C>T (p.R225X) of PHF6 gene was identified in the patient, inherited from her unaffected mother. Both the patient and her mother showed highly skewed X-inactivation. We reviewed the phenotypes of all reported BFLS cases, and summarized their endocrine presentations. This first report of an Asian patient with BFLS further delineated the genetic and phenotypic spectrum of the syndrome. The adverse effect experienced by the patient suggests caution in the use of growth hormone treatment in this condition.

Examining the blood amino acid status in pretherapeutic patients with hyperphenylalaninemia

Background

Hyperphenylalaninemia is the most common genetic metabolic disease. Early treatment prevents brain injury effectively. The present study aimed to detect the exact amino acid status of patients with hyperphenylalaninemia before treatment.

Methods

Data of 116 newborn patients from our Newborn Screening Center and 161 older patients from our clinic before treatment were collected. The content of 17 amino acids in their blood was determined by tandem mass spectrometry and compared with normal controls. Relationship between phenylalanine and other amino acids in patients was analyzed using the smoothing curve fitting and threshold effect analysis.

Results

Most amino acids in the blood of patients were within the normal range; however, they were different significantly from those of the normal children. Newborn patients showed higher phenylalanine (346.30 vs 45.90 µmol/L), valine (121.50 vs 110.30 µmol/L), citrulline, ornithine and lower tyrosine (52.97 vs 66.12 µmol/L), threonine (68.68 vs 78.21 µmol/L), glutamine levels than observed in normal newborns. Older patients showed significantly higher phenylalanine (844.00 vs 51.82 µmol/L), valine (117.60 vs 110.90 µmol/L), histidine, serine and lower tyrosine (55.97 vs 67.31 µmol/L), threonine (35.94 vs 51.89 µmol/L), alanine, asparagine, glutamic acid, methionine, arginine, glycine, ornithine, glutamine content than found in matched normal children. Tyrosine, valine, ornithine, and threonine in newborn patients and tyrosine, glycine, glutamine, and threonine in older patients had a nonlinear correlation with phenylalanine levels with obvious threshold effect and clear inflection points.

Conclusion

Significant difference was observed in the amino acid status between pretherapeutic hyperphenylalaninemia patients and normal children. Some amino acids showed notable threshold effect with phenylalanine level in a nonlinear pattern.

[The role of S100A8/RAGE and Caveolin-1 and the effect of roxithromycin on their expression in a rat model of neutrophilic asthma]

Objective: To explore the role of S100A8, the receptor for advanced glycation endproducts (RAGE) and Caveolin-1 in neutrophilic asthmatic rats, and to further study the intervention of roxithromycin and the possible mechanisms. Methods: Male Brown Norway rats were randomly assigned to a control group, an asthma group and a Roxithromycin group. The asthmatic rat model was established by intraperitoneal injection of ovalbumin (OVA) and Freund's complete adjuvant (FCA) mixture, and aerosol inhalation of OVA. Rats in the Roxithromycin group were given roxithromycin injection 30 mg/kg 30 minutes before each challenge. Rats in the control and the asthma groups were replaced with equal volumes of saline, respectively. Bronchoalveolar lavage fluid (BALF) neutrophil percentage (Neu%) and pathological changes of pulmonary tissue (hematoxylin-eosin, HE staining) were measured to confirm the establishment of asthmatic models. The concentration of inflammatory cytokines and S100A8 were quantified by enzyme-linked immunosorbent assay (ELISA), and the expression of Caveolin-1 and RAGE at protein levels were detected by immunohistochemistry and Western blot. Results: Neu% in BALF of the asthma group was significantly higher than those of the control group, and Neu% in the Roxithromycin group was lower than the asthma group (all P<0.01). Pulmonary histology revealed that there were a large number of inflammatory cells infiltrated in the bronchial and perivascular, pulmonary interstitial and alveolar spaces, and the bronchial wall and smooth muscles were thickened obviously in the asthma group. Rats in the Roxithromycin group showed milder inflammation and airway remodeling change than the asthma group. There was no obvious pathological damage in the control group. The concentration of IL-6 and IL-17 in BALF and serum of rats in the asthma group were significantly higher than those in the control group (P<0.01), and Roxithromycin inhibited the high expression of these cytokines (P<0.05). The expression of S100A8 and RAGE in the asthma group were significantly higher than those in the control group [(20.6±4.4) vs (7.1±2.0) ng/L; (885±118) vs (462±102) ng/L; (14.2±1.7) vs (7.6±1.8) ng/L; (774±166) vs (406±69) ng/L, all P<0.05], and Roxithromycin inhibited the high expression of these proteins [(14.3±3.7) vs (20.6±4.4) ng/L; (650±53) vs (885±118) ng/L; (10.4±1.2) vs (14.2±1.7) ng/L; (560±64) vs (728±72) ng/L] (all P<0.05). Meanwhile, the expression of Caveolin-1 in the asthma group was significantly lower than that in the control group (P<0.01), and Roxithromycin up-regulated its expression (P<0.01). Correlation analysis showed that there was a significantly positive correlation between the expression of S100A8 and RAGE (r=0.706, P<0.01), while there was a significantly negative correlation between the expression of S100A8 and Caveolin-1 (r=-0.775, P<0.01), and between the expression of Caveolin-1 and RAGE (r=-0.919, P<0.01). Conclusion: S100A8 and Caveolin-1 may play an important role in neutrophilic asthma via RAGE, and Roxithromycin may exerts anti-inflammatory effects and inhibition of airway remodeling partly through this signaling pathway.

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.

[Expression of RAGE in asthmatic rats and the intervention of Roxithromycin]

Objective: To observe the expression of the Receptor of Advanced glycation end products (RAGE) in asthmatic rats, and explore the intervention of Roxithromycin. Methods: A total of 18 Specific Pathogen Free-class Brown Norway male rats were randomly divided into control group, asthma model group and Roxithromycin group, with 6 rats in each group. The asthmatic model was sensitized by intraperitoneal injection of Ovalbumin (OVA)+Al(OH)(3), and challenged with OVA. Rats in Roxithromycin group were given Roxithromycin 30 mg/kg 30 minutes before each challenge. Rats in control group and asthma model group were treated with equal volume of saline. The concentrations of RAGE and interleukin (IL)-4 in serum and bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent (ELISA); the pathological changes of lung tissues were observed by HE-staining; the thickness of airway wall and airway smooth muscle were measured by Image-Pro Plus; the relative expression of RAGE in lung tissues were detected by Western blot. Results: In asthma model group, the concentrations of RAGE and IL-4 in the serum and BALF were obviously higher than those in control group [(494±32) vs (327±45) ng/L; (32.4±5.8) vs (13.1±2.9) ng/L; (553±38) vs (399±56) ng/L; (37.8±3.4) vs (19.4±2.5) ng/L] (all P<0.01); in Roxithromycin group, the concentrations of RAGE and IL-4 in the serum and BALF were obviously lower than those in asthma model group [(438±18) vs (494±32) ng/L; (22.8±6.0) vs (32.4±5.8) ng/L; (444±42) vs (553±38) ng/L; (25.6±4.5) vs (37.8±3.4) ng/L] (all P<0.05). In asthma model group, the bronchial wall was thickened, the lumen was narrow, the mucosal wrinkles were significantly increased, edema appeared under the mucosa, and a large number of inflammatory cells infiltrated and aggregated in the bronchi, perivascular and alveolar spaces; the thickness of airway wall and airway smooth muscle were significantly increased than those in control group (P<0.01); in Roxithromycin group, airway inflammation and remodeling were alleviated compared with those in asthma model group (P<0.05). In asthma model group, the expression of RAGE in lung tissues were significantly increased than those in control group (P<0.01); in Roxithromycin group, the expression of RAGE were significantly decreased than those in asthma model group (P<0.01). There were positive correlations between the expression of RAGE and IL-4 in BALF and serum (r=0.782, 0.804, all P<0.01); there were positive correlations between RAGE and total white cell counts, eosinophil counts, smooth muscle thickness (r=0.897, 0.927, 0.860, all P<0.01). Conclusions: The increasing of RAGE in asthmatic rats are positively correlated with airway inflammation and airway remodeling. Roxithromycin may inhibit the development of asthma by reducing the expression of RAGE.

[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.

Prenatal diagnosis of methylmalonic aciduria from amniotic fluid using genetic and biochemical approaches

OBJECTIVES

This study reported the clinical prenatal diagnosis experience of families affected by methylmalonic acidemia (MMA) evaluated at a single prenatal diagnosis center over 8 years, and the reliability of a biochemical approach for prenatal diagnosis was analyzed.

METHODS

Prenatal diagnosis data for 187 MMA families referred to our center from 2009 to 2016 were reviewed retrospectively. The results of the genetic analysis and biochemical approach were compared.

RESULTS

A total of 41 MMA-affected pregnancies (21%) were identified. The biochemical analysis could identify the true status of 99.5% of fetuses. The diagnostic sensitivities of the propionylcarnitine (C3) level, the C3 to acetylcarnitine (C2) ratio (C3/C2), the methylmalonic acid, and methylcitrate levels in the amniotic fluid were 95.1%, 100%, 100%, and 82.9%, respectively, and the specificities were 98.7%, 99.3%, 97.4%, and 96.7%, respectively.

CONCLUSIONS

The biochemical analysis could be optionally used in the prenatal diagnosis of MMA, especially in cases where the genetic results are inconclusive. Among the four tested biochemical markers, C3/C2 appeared to be the most reliable.

Aggregation of Gold Nanoparticles Caused in Two Different Ways Involved in 4-Mercaptophenylboronic Acidand Hydrogen Peroxide

The difference in gold nanoparticle (AuNPs) aggregation caused by different mixing orders of AuNPs, 4-mercaptophenylboronic acid (4-MPBA), and hydrogen peroxide (H₂O₂) has been scarcely reported. We have found that the color change of a ((4-MPBA + AuNPs) + H₂O₂) mixture caused by H₂O₂ is more sensitive than that of a ((4-MPBA + H₂O₂) + AuNPs) mixture. For the former mixture, the color changes obviously with H₂O₂ concentrations in the range of 0~0.025%. However, for the latter mixture, the corresponding H₂O₂ concentration is in the range of 0~1.93%. The mechanisms on the color change originating from the aggregation of AuNPs occurring in the two mixtures were investigated in detail. For the ((4-MPBA + H₂O₂) + AuNPs) mixture, free 4-MPBA is oxidized by H₂O₂ to form bis(4-hydroxyphenyl) disulfide (BHPD) and peroxoboric acid. However, for the ((4-MPBA+AuNPs) + H₂O₂) mixture, immobilized 4-MPBA is oxidized by H₂O₂ to form 4-hydroxythiophenol (4-HTP) and boric acid. The decrease in charge on the surface of AuNPs caused by BHPD, which has alarger steric hindrance, is poorer than that caused by -4-HTP, and this is mainly responsible for the difference in the aggregation of AuNPs in the two mixtures. The formation of boric acid and peroxoboric acid in the reaction between 4-MPBA and H₂O₂ can alter the pH of the medium, and the effect of the pH change on the aggregation of AuNPs should not be ignored. These findings not only offer a new strategy in colorimetric assays to expand the detection range of hydrogen peroxide concentrations but also assist in deepening the understanding of the aggregation of citrate-capped AuNPs involved in 4-MPBA and H₂O₂, as well as in developing other probes.

Characteristics of Pompe disease in China: a report from the Pompe registry

Background

Pompe disease is a rare, progressive, autosomal recessive lysosomal storage disorder caused by mutations in the acid α-glucosidase gene. This is the first report of Chinese patients from the global Pompe Registry. Chinese patients enrolled in the Registry (ClinicalTrials.gov, NCT00231400) between Jan 2013 and 2 Sep 2016 with late onset Pompe disease (LOPD; presentation after 12 months of age or presentation at ≤12 months without cardiomyopathy) were included. Data analyses were descriptive.

Results

Of the 59 Chinese patients included, 86.4% had never received enzyme replacement therapy (ERT). The age at symptom onset and diagnosis was 14.9 (12.35) and 22.1 (10.08) years, which is younger than previous reports of LOPD patients from the rest of the world (28.4 [18.86] and 34.9 [20.03], respectively). The most common diagnosis methods were enzyme assay (79.7%) and/or DNA analysis (61.0%). Of the 36 patients diagnosed using DNA analysis, 31 had standardized variant data and among these patients the most common mutations were c.2238G > C (n = 18, 58.1%) and c.2662G > T (n = 5, 16.1%). Chinese LOPD patients appeared to have worse lung function versus patients from the rest of the world, indicated by lower forced vital capacity (37.2 [14.00]% vs. 63.5 [26.71]%) and maximal expiratory and inspiratory pressure (27.9 [13.54] vs. 51.0 [38.66] cm H₂O, and 29.4 [12.04] vs. 70.5 [52.78] cm H₂O).

Conclusions

Compared with patients from the rest of the world, Chinese patients with LOPD appeared to have younger age at symptom onset and diagnosis, lower lung function, and the majority had not received ERT. The most common mutations were c.2238G > C and c.2662G > T.

Electronic supplementary material

The online version of this article (10.1186/s13023-019-1054-0) contains supplementary material, which is available to authorized users.

Crystal structure of catena-poly[dichlorido-(μ2-3-(2-pyridyl)-4-(4-pyridyl)-5-(3-pyridyl)-1,2,4-triazole-κ2 N:N′)] copper(II), C17H12N6Cl2Cu

C17H12Cl2CuN6, monoclinic, P21/c (no. 14), a = 13.113(3) Å, b = 7.1325(4) Å, c = 19.527(3) Å, β = 103.628(2)°, V = 1774.8(5) Å3, Z = 4, R gt(F) = 0.0310, wR ref(F 2) = 0.0682, T = 296(2) K.