Results of a Pilot External Quality Assessment Scheme for Genetic Testing of Newborns with Spinal Muscular Atrophy.

BACKGROUND: This study aims to evaluate the ability of laboratories to perform spinal muscular atrophy (SMA) genetic testing in newborns based on dried blood spot (DBS) samples, and to provide reference data and advance preparation for establishing the pilot external quality assessment (EQA) scheme for SMA genetic testing of newborns in China. METHODS: The pilot EQA scheme contents and evaluation principles of this project were designed by National Center for Clinical Laboratories (NCCL), National Health Commission. Two surveys were carried out in 2022, and 5 batches of blood spots were submitted to the participating laboratory each time. All participating laboratories conducted testing upon receiving samples, and test results were submitted to NCCL within the specified date. RESULTS: The return rates were 75.0% (21/28) and 95.2% (20/21) in the first and second surveys, respectively. The total return rate of the two examinations was 83.7% (41/49). Nineteen laboratories (19/21, 90.5%) had a full score passing on the first survey, while in the second survey twenty laboratories (20/20, 100%) scored full. CONCLUSIONS: This pilot EQA survey provides a preliminary understanding of the capability of SMA genetic testing for newborns across laboratories in China. A few laboratories had technical or operational problems in testing. It is, therefore, of importance to strengthen laboratory management and to improve testing capacity for the establishment of a national EQA scheme for newborn SMA genetic testing.

Genotype characterization of tetrahydrobiopterin deficiency in two Tibetan children.

Background: Tetrahydrobiopterin (BH4) deficiency is a rare cause of hyperphenylalaninemia (HPA). The incidence of this condition varies based on region and ethnicity. In the early stages, patients typically do not exhibit any symptoms, and HPA is identified only through newborn screening for diseases. It is important to distinguish BH4 deficiency from phenylketonuria (PKU, MIM # 261600). Timely diagnosis and treatment of BH4 deficiency are crucial for the prognosis of patients. Case presentation: We present two rare cases of Chinese Tibetan children with BH4D, diagnosed through biochemical tests and genetic sequencing. Case 1 is a male infant, 2 months old, with a newborn screening (NBS) Phe level of 1212 µmol/L (reference range <120 µmol). The biopterin(B) level was 0.19 mmol/molCr (reference range: 0.42-1.92 mmol/molCr), with a B% of 5.67% (reference range: 19.8%-50.3%). Gene sequencing revealed a homozygous missense variant [NM_000317.3 (PTS): c.259C > T (p.Pro87Ser), rs104894276, ClinVar variation ID: 480]. The patient was treated with a Phe-reduced diet and oral sapropterin, madopar and is currently 3 years and 4 months old, showing mild global developmental delay. Case 2 is a 40-day-old female infant with a Phe level of 2442.11 µmol/L and dihydropteridine reductase (DHPR) activity of 0.84 nmol/(min. 5 mm disc) (reference range: 1.02-3.35 nmol/min.5 mm disc. Gene sequencing revealed a compound heterozygous genotype [NM_000320.3(QDPR): c.68G > A (p.Gly23Asp), rs104893863, ClinVar Variation ID: 490] and [NM_000320.3(QDPR) c.419C > A (p. Ala140Asp), ClinVar ID: 2444501]. The patient was treated with a Phe-reduced diet and oral madopar, 5-hydroxytryptophan. At the age of 1 year, she exhibited severe global developmental delay with seizures. Conclusion: We identified and treated two cases of BH4D in Tibetan populations in China, marking the first confirmed instances. Our report emphasizes the significance of conducting differential diagnosis tests for BH4D.

Genetic analysis of a pedigree with MECP2 duplication syndrome in China.

BACKGROUND: MECP2 duplication syndrome (MDS) is a rare X-linked genomic disorder that primarily affects males. It is characterized by delayed or absent speech development, severe motor and cognitive impairment, and recurrent respiratory infections. MDS is caused by the duplication of a chromosomal region located on chromosome Xq28, which contains the methyl CpG binding protein-2 (MECP2) gene. MECP2 functions as a transcriptional repressor or activator, regulating genes associated with nervous system development. The objective of this study is to provide a clinical description of MDS, including imaging changes observed from the fetal period to the neonatal period. METHODS: Conventional G-banding was employed to analyze the chromosome karyotypes of all pedigrees under investigation. Subsequently, whole exome sequencing (WES), advanced biological information analysis, and pedigree validation were conducted, which were further confirmed by copy number variation sequencing (CNV-seq). RESULTS: Chromosome karyotype analysis revealed that a male patient had a chromosome karyotype of 46,Y,dup(X)(q27.2q28). Whole-exon duplication in the MECP2 gene was revealed through WES results. CNV-seq validation confirmed the presence of Xq27.1q28 duplicates spanning 14.45 Mb, which was inherited from a mild phenotype mother. Neither the father nor the mother's younger brother carried this duplication. CONCLUSION: In this study, we examined a male child in a family who exhibited developmental delay and recurrent respiratory tract infections as the main symptoms. We conducted thorough family investigations and genetic testing to determine the underlying causes of the disease. Our findings will aid in early diagnosis, genetic counseling for male patients in this family, as well as providing prenatal diagnosis and reproductive guidance for female carriers.

Vulto-van Silfhout-de Vries syndrome caused by de novo variants of DEAF1 gene: a case report and literature review.

Vulto-van Silfhout-de Vries syndrome (VSVS; MIM 615828) is an extremely rare autosomal dominant disorder with unknown incidence. It is always caused by de novo heterozygous pathogenic variants in the DEAF1 gene, which encodes deformed epidermal autoregulatory factor-1 homology. VSVS is characterized by mild to severe intellectual disability (ID) and/or global developmental delay (GDD), seriously limited language expression, behavioral abnormalities, somnipathy, and reduced pain sensitivity. In this study, we present a Chinese boy with moderate GDD and ID, severe expressive language impairment, behavioral issues, autism spectrum disorder (ASD), sleeping dysfunction, high pain threshold, generalized seizures, imbalanced gait, and recurrent respiratory infections as clinical features. A de novo heterozygous pathogenic missense variant was found in the 5th exon of DEAF1 gene, NM_021008.4 c.782G>C (p. Arg261Pro) variant by whole exome sequencing (WES). c.782G>C had not been previously reported in genomic databases and literature. According to the ACMG criteria, this missense variant was considered to be "Likely Pathogenic". We diagnosed the boy with VSVS both genetically and clinically. At a follow-up of 2.1 years, his seizures were well controlled after valproic acid therapy. In addition, the child's recurrent respiratory infections improved at 3.5 years of age, which has not been reported in previous individuals. Maybe the recurrent respiratory infections like sleep problems reported in the literature are not permanent but may improve naturally over time. The literature review showed that there were 35 individuals with 28 different de novo pathogenic variants of DEAF1-related VSVS. These variants were mostly missense and the clinical manifestations were similar to our patient. Our study expands the genotypic and phenotypic profiles of de novo DEAF1.

Study on Color Quantitative Expression, Replication and Color Origin of Gray-Purple Nephrite from Qinghai, China Based on Spectroscopy Methods.

Color is one of the most important factors in evaluating the quality and price of jewelry. Quantitative research on color of jewels has been a hotspot in gemological science. Whether for jewelry industry or gems research, observing and describing the gems' color characteristics under transmission light is an essential method. This study focuses on building a research method to quantitatively characterize nephrite color, and to determine their color origin based on transmitted spectroscopy techniques. Natural gray-purple nephrite of Sanchahe mining, Qinghai, China was chosen as a typical subject due to its gradual-change color characteristic. We first quantitatively expressed and replicated the different color region on a gray-purple nephrite sample with given thickness (1.0 mm) with UV-Visible absorption spectra and 1976 CIE L*a*b* colorimetric parameters, as well as Adobe Photoshop software. The replicated color of light and dark color regions were both close to the transmitted color observed by naked eyes. It is inferred that the subtle color differences between naked eyes observation and transmitted spectroscopy replication may from the multiple effects of incident light in translucent polycrystalline structure, such as absorption, refraction, diffraction, scattering, and so on. As for the purple color origin, Laser Ablation Inductively Coupled Plasma Mass Spectroscopy (LA-ICP-MS) showed an increase of the concentrations of manganese (Mn) as the nephrite color becomes darker. Moreover, the emission peak at 585 nm on Photoluminescence (PL) and absorption peak at 530 nm on Ultraviolet Visible (UV-Vis), and the sextet Mn2+ resonance peaks on Electronic Paramagnetic Resonance (EPR) provide solid support to prove that Mn2+ should be the main factor contributing to the purple color. This work provides a specific experimental method on quantitative observing and describing the color of gems under transmitted light, and it also offers valuable information on determining the chromophores and color origin.

A Chimera Polypeptide with Active Sites of HWTX-I and AAI.

The functional amino acid sequence and its neighbouring fragments in the molecule of Amaranth alpha-amylase inhibitor isolated from seeds of the Mexican crop plant Amaranthus hypochondriacus were transferred, by solid phase chemical synthesis, into N-terminal region of the huwentoxin-I(HWTX-I). The synthetic chimera polypeptide was confirmed by Edman degradation and MALDI-TOF mass spectroscopy. The formation of three disulfide bonds and special conformation of the synthetic chimera was induced by the addition of glutathione. Renatured chimera polypeptide was purified by ion-exchange and reversed phase HPLC. The results showed that the engineered chimera polypeptide exerted obvious inhibitory activity to alpha-amylase from digestive tube of the roach (Periplaneta Americana) at pH 5.5 with the concentration of 9.5x10(-5) mol/L, and also exerted 36% of the neurotoxic activity of the natural huwentoxin-I as shown by the experiments of blockage of the neuromuscular transmission of isolated mouse phrenic nerve-diaphragm preparations. The experiments demonstrated that the structural motif of HWTX-I is well promising for protein engineering, and the solid-phase peptide synthesis is adequate rapid for the engineering of artificially designed small proteins.