Hereditary myopathy with early respiratory failure is a titin （TTN）-related myopathy caused by mutations in the A-band of the TTN gene.This condition is characterized by distinctive clinical and pathological features， as well as a typical skeletal muscle involvement pattern. We report a 43-year-old male patient with progressive distal limb weakness over the past three years. The initial symptom was difficulty in lifting both feet， followed by difficulty in extending the dorsum of both hands one year later. However， the patient never experienced dyspnea. The patient's past medical history was unremarkable， and there was no family history of inherited diseases.His parents were healthy. Physical examination revealed wrist drop and noticeable atrophy of the tibialis anterior in both calves. Muscle strength in the lower limbs was graded at 4 for proximal muscles and 2 for distal muscles.Laboratory tests showed a creatine kinase level of 375U/L（normal range：50~310）. Electromyography revealed myogenic injury in the bilateral tibialis anterior and the right extensor digitorum communis. Magnetic resonance imaging of the muscles showed isolated involvement of the semitendinosus muscle with severe fatty infiltration， along with significant fatty degeneration of the anterior calf muscles. Muscle biopsy of the proband showed subsarcolemmal “necklace-like” cytoplasmic bodies and the “erasure” phenomenon on NADH enzyme histochemistry. Both electrocardiogram and echocardiography showed no abnormalities. Exome sequencing of the proband identified a missense mutation in the TTN gene， c.95358C>G， p.Asn31786Lys. Sanger sequencing confirmed that the mutation was absent in both parents of the proband， indicating a de novo mutation.

21 hydroxylase deficiency (21-OHD), the most common form of congenital adrenal hyperplasia, is caused by defects in CYP21A2 gene, which encodes the cytochrome P450 oxidase (P450C21) involved in glucocorticoid and mineralocorticoid synthesis. The diagnosis of 21-OHD is based on the comprehensive evaluation of clinical manifestation, biochemical alteration and molecular genetics results. Due to the complex structure of CYP21A2, special techniques are required to perform delicate analysis to avoid the interference of its pseudogene. Recently, the state-of-the-art diagnostic methods were applied to the clinic gradually, including the steroid hormone profiling and third generation sequencing. To standardize the laboratory diagnosis of 21-OHD, this consensus was drafted on the basis of the extensive knowledge, the updated progress and the published consensuses and guidelines worldwide by expert discussion organized by Rare Diseases Group of Pediatric Branch of Chinese Medical Association, Medical Genetics Branch of Chinese Medical Doctor Association, Birth Defect Prevention and Molecular Genetics Branch of China Maternal and Child Health Association. and Molecular Diagnosis Branch of Shanghai Medical Association.
Child ; Humans ; Adrenal Hyperplasia, Congenital/genetics* ; Steroid 21-Hydroxylase/genetics* ; Consensus ; China ; Clinical Laboratory Techniques ; Mutation

Objective:To analyze the disease spectrum of lysosomal storage disorders(LSDs) and explore the prevalent distributions of different LSD types in one center in Shanghai.Methods:A retrospective analysis was made.A total of 5 476 suspected LSD patients, including 3 415 males and 2 061 females, with a median age of 4 years(1 day to 72 years), were collected from Xinhua Hospital, Shanghai Jiaotong University School of Medicine from August 2008 to May 2022.The activity of different lysosomal enzymes was detected by fluorescent and biochemical methods.Results:A total of 1 520 patients were diagnosed with LSDs, including 972 males and 548 females, with a median age of 4 years(1 day to 59 years), involving 19 different subtypes.Mucopolysaccharidosis(MPS) was the most common type among LSDs, with a frequency of 45.46%(691/1 520), followed by sphingolipidoses [33.88%(515/1 520)] and glycogen storage disease type Ⅱ [16.05%(244/1 520)] successively.MPS Ⅱ was the most common type in MPS, with a frequency of 45.73%(316/691), followed by MPS ⅣA [22.87%(158/691)]. Niemann-Pick A/B, Gaucher, and Krabbe diseases were common in Sphingolipidoses patients, with frequencies of 37.09%(191/515), 34.37%(177/515), and 10.29%(53/515), respectively.Conclusions:LSDs are common genetic metabolic diseases, especially MPS and sphingolipidoses.Newborn screening for LSDs should be carried out timely so that the patients can be treated early and their prognosis can be improved.

Neonatal screening is one of the crucial parts of the tertiary prevention strategy to reduce congenital disability. Traditional neonatal screening, mainly focusing on genetic metabolic diseases, has limitations in disease types and requires genetic testing for further validation and accurate typing. Currently, conducting genetic screening based on biochemical metabolite screening has become the trend in neonatal screening. This article synthesizes the current state of neonatal genome screening at home and abroad. Herein, the comprehensive concepts of "SNV Plus" (single nucleotide variation plus) and "CNV Plus" (copy number variation plus) have been proposed to develop a new technology that can detect the gene structure of SNV and CNV simultaneously and improve the level of neonatal genome screening based on characteristics of the pathogenic gene structure.
DNA Copy Number Variations ; Humans ; Infant, Newborn ; Neonatal Screening ; Nucleotides

Newborn screening is an effective measure for early detection and early treatment of rare genetic diseases. Among the three-level preventive measures to reduce birth defects, newborn screening has a significant preventive effect, and continues to develop with the advancement of new therapies and new technologies. Newborn screening is also relatively more reliable to obtain data on the prevalence of rare diseases. This article introduces the history and current status of neonatal screening for newborn hereditary metabolic disease in China, presents the disease spectrum and prevalence of 7 819 662 cases of neonatal screening by tandem mass spectrometry, and proposes 12 rare diseases as the primary targeting diseases for newborn screening by tandem mass spectrometry in China. At last, the article raises and discusses the issues of requirement for technology development and ethics of newborn screening.

Objective:To explore the clinical characteristics, genotypes and long-term outcomes of individuals with 3-methylglutaconic aciduria.Methods:The clinical features, biochemical data, genetic test results and treatment outcomes of six children with 3-methylglutaconic aciduria admitted to the Department of Endocrinology, Genetics and Metabolism, Xinhua Hospital from February 2017 to February 2019 were retrospectively analyzed and the Gesell developmental diagnosis schedule was performed to evaluate the development of four patients.Results:Among 6 children with 3-methylglutaconic aciduria 2 were males and 4 were females.Four cases had 3-methylglutaconic aciduria type Ⅰ and 2 cases had 3-methylglutaconic aciduria with deafness,encephalopathy, and Leigh-like syndrome. Five of 6 patients were detected by newborn screening among whom 4 remained asymptomatic, and only one had a postmortem diagnosis. Among them, 4 patients remained asymptomatic, while two presented with clinical symptoms such as jaundice and dyspnea and the age of disease onset was 1 and 2 days respectively. The concentration of 3-methylglutaconic acid in urine of all affected individuals was between 22.38 and 77.09 mmol/molCr, which was above the normal value. Genetic tests were performed for all patients. Eleven variants were identified in 2 genes, of which 10 variants were novel and only c.442C>T p.(R148X) has been previously reported; Seven variants (c.656-2delA, EX5-EX6 Del, c.942+3A>G, c.373C>T p.(R125W), c.895-3C>G, c.667C>T p.(R223X) and c.894+5G>A) were in AUH gene. The others (c.548G>A p.(R138Q), c.442C>T p.(R148X), c.1339C>T p.(R447X) and c.973dupA p.(M325Nfs*5) were in SERAC1 gene. After being treated with leucine diet restriction and L-carnitine, 4 patients with AUH gene variation who were from asymptomatic phase developed normally, whereas those 2 patients with SERAC1 gene variation had a poor prognosis. During the follow-up, 2 patients exhibited varying degrees of psychomotor retardation, the rest had normal course of development.Conclusions:There are significant clinical heterogeneities among individuals with 3-methylglutaconic aciduria. The most common pathogenic variants are splicing variations, followed by nonsense, missense and frameshift mutations. Leucine-free diet and oral L-carnitine therapy are effective for some patients. Newborn screening is essential for early diagnosis and improvement of prognosis.

Objective:To analyze the pathological features of facioscapulohumeral muscular dystrophy (FSHD). For better characterization of inflammatory response in FSHD, we performed histochemical morphological analysis for FSHD and polymyositis (PM) muscle biopsies.In order to provide a reference for guide targeted therapeutic interventions.Methods:The clinical and myopathological data of 30 patients with FSHD from January 2006 to January 2019 in the Sixth Hospital of Shanxi Medical University and the first hospital of Jilin University were retrospectively analyzed. The patients were divided into non-inflammatory infiltration group (16 cases) and inflammatory infiltration group (14 cases) according to the presence or absence of inflammatory cell infiltration. For better characterization of inflammatory response in FSHD, we performed histochemical morphological analysis for two groups of muscles: FSHD and PM muscle biopsies, using Image-Pro plus bioanalytical software.Results:In 30 cases of FSHD, 14 cases showed intramuscular and interstitial inflammatory cell infiltration, especially around the blood vessels. Immunohistochemical staining confirmed that the infiltration of inflammatory cells was mainly CD4 + T lymphocytes. Morphometric analysis showed that there were no significant differences in muscle fiber surface area, density, diameter, inflammatory cell infiltration, regeneration and necrosis between FSHD patients and PM patients ( P>0.05). The total area of myointerstitium in FSHD group was significantly larger than that in PM group ( P=0.03). Conclusions:The pathological morphometric analysis showed that the proliferation of interstitial connective tissue in FSHD inflammatory cell infiltration group was significantly more than that in PM group. Clinicians can identify the two from pathology and provide help for clinical practice.

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.

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.

Objective: To investigate the effect of pseudodeficiency alleles on the newborn screening of glycogen storage disease type Ⅱ(GSDⅡ) by using afluorometric enzymatic assay to determine acid α-glucosidase (GAA) activity in dried blood spot (DBS). Methods: A total of 30 507 newborns′ DBSs, obtained from Newborn Screening Center of Xinhua Hospital Shanghai Jiao Tong University School of Medicine from May to December 2017, were screened for GSD Ⅱ by fluorometric enzymatic assay of GAA activity. The suspected positive DBSs after the first and second screening were directly analyzed by Sanger sequencing of GAA to confirm the diagnosis. Retrospective analysis of 3 172 controls without GSDⅡand 36 GSD Ⅱ patients were conducted to investigate the carrier status of pseudodeficiency alleles. Statistical analysis of frequency of pseudodeficiency alleles were carried out by Chi-square test or Fisher exact probability test. Results: GAA activity of 30 507 newborns showed a positively skewed distribution.Twenty-nine cases of newborns, suspected to be GSDⅡwere confirmed to be normal with genetic analysis of the original DBSs. Among the 29 suspected positive cases, 24 cases were homozygous for pseudodeficiency alleles c.[1726A/A; 2065A/A], and the other 5 cases were c.[1726G/A; 2065G/A] heterozygote. The frequency of c.1726G>Ahomozygote in 3 172 non-GSD Ⅱcontrols was 2.08% (66/3 172), and c.1726G>A homozygote occurred in allelic conjunction with c.2065G>Ahomozygote. Frequency of c.[1726A; 2065A] haplotype in 3 172 controls was 3.2%(206/6 344). Frequency of c.[1726A/A; 2065A/A] homozygote in 36 GSDⅡpatients (16.67%, 6/36) was significantly higher than that in non-GSD Ⅱcontrols(2.08%, 66/3 172) (χ²=34.517, P<0.001). Conclusions Pseudodeficiency alleles show a high frequency in Chinese, which leads to a high false positive rate in the newborns screening of GSDⅡ.The afterword genetic analysis of the original DBS after the GAA activity screening could reduce the effect of pseudodeficiency alleles on the newborns screening of GSDⅡ.