The energy metabolism of Balantidium polyvacuolum inhabiting the hindgut of Xenocypris davidi.

Anaerobic parasitic ciliates are a specialized group of ciliates that are adapted to anoxic and oxygen-depleted habitats. Among them, Balantidium polyvacuolum, which inhabits the hindgut of Xenocyprinae fishes, has received very limited scientific attention, so the molecular mechanism of its adaptation to the digestive tract microenvironment is still unclear. In this study, transmission electron microscopy (TEM) and single-cell transcriptome analysis were used to uncover the metabolism of B. polyvacuolum. Starch granules, endosymbiotic bacteria, and multiple specialized mitochondrion-related organelles (MROs) of various shapes were observed. The MROs may have completely lost the electron transport chain (ETC) complexes I, III, IV, and V and only retained succinate dehydrogenase subunit A (SDHA) of complex II. The tricarboxylic acid (TCA) cycle was also incomplete. It can be inferred that the hypoxic intestinal environment has led to the specialization of the mitochondria in B. polyvacuolum. Moreover, carbohydrate-active enzymes (CAZymes), including carbohydrate esterases, enzymes with a carbohydrate-binding module, glycoside hydrolases, and glycosyltransferases, were identified, which may constitute evidence that B. polyvacuolum is able to digest carbohydrates and starch. These findings can improve our knowledge of the energy metabolism and adaptive mechanisms of B. polyvacuolum.

[Clinical features and C12orf65 mutations of autosomal recessive spastic paraplegia-55: a case report].

This article reports the clinical features and C12orf65 gene mutations of a girl with autosomal recessive spastic paraplegia-55. The 8-year-old girl experienced disease onset at the age of 5 years and had optic atrophy as the main clinical manifestation, with slow movements in standing up and a slight duck-shaped gait. Peripheral blood DNA samples were collected from this child and her parents and brother to perform high-throughput whole-exome sequencing and high-throughput mitochondrial genome sequencing. Sanger sequencing was performed for verification. The results showed two compound heterozygous mutations, c.394C>T and c.447_449delGGAinsGT, in the C12orf65 gene. The former mutation came from her father and was a known pathogenic mutation, and the latter came from her mother and was a novel mutation which had not been reported in literature. This study expands the mutation spectrum of the C12orf65 gene and thus provides a molecular basis for the etiological diagnosis of the child and the genetic counseling of the family.

[NIPBL gene mutations in two children with Cornelia de Lange syndrome].

Both children (one boy and one girl) experienced disease onset in infancy and visited the hospital due to growth retardation. They had unusual facies including thick hair, arched and confluent eyebrows, long and curly eyelashes, short nose, and micrognathia. Patient 1 had congenital heart disease (atrial septal defect and pulmonary stenosis) and special dermatoglyph (a single palmar crease). Patient 2 had cleft palate and moderate-to-severe deafness. Clinical features suggested Cornelia de Lange syndrome in both children. High-throughput sequencing was used to detect the seven known pathogenic genes of Cornelia de Lange syndrome, i.e., the NIPBL, SMC1A, SMC3, HDAC8, RAD21, EP300, and ANKRD11 genes. Sanger sequencing was used to analyze and verify gene mutations. Both patients were found to have novel mutations in the NIPBL gene. One patient had a frameshift mutation in exon 45, c.7834dupA, which caused early termination of translation and produced truncated protein p.R2612fsX20. The other patient had a nonsense mutation, c.505C>T, which caused a premature stop codon and produced truncated protein Q169X. Such mutations were not found in their parents or 50 unrelated healthy individuals.

Long intergenic non-coding RNA 00152 promotes lung adenocarcinoma proliferation via interacting with EZH2 and repressing IL24 expression.

BACKGROUND: Numerous studies have shown that long non-coding RNAs (lncRNAs) behave as a novel class of transcript during multiple cancer processes, such as cell proliferation, apoptosis, migration, and invasion. LINC00152 is located on chromosome 2p11.2, and has a transcript length of 828 nucleotides. The biological role of LINC00152 in LAD(lung adenocarcinoma) remains unknown. METHODS: Quantitative reverse transcription PCR(qRT-PCR) was used to detect LINC00152 expression in 60 human LAD tissues and paired normal tissues. In vitro and in vivo studies showed the biological function of LINC00152 in tumour progression. RNA transcriptome sequencing technology was performed to identify the downstream suppressor IL24(interleukin 24) which was further examined by qRT-PCR, western bolt and rescue experiments. RNA immunoprecipitation (RIP), RNA pulldown, and Chromatin immunoprecipitation (ChIP) assays were carried out to reveal the interaction between LINC00152, EZH2 and IL24. RESULTS: LINC00152 expression was upregulated in 60 human LAD tissues and paired normal tissues. High levels of LINC00152 expression were correlated with advanced TNM stage, larger tumor size, and lymph node metastasis, as well as shorter survival time. Silencing of LINC00152 suppressed cell growth and induced cell apoptosis. LINC00152 knockdown altered the expression of many downstream genes, including IL24. LINC00152 could interact with EZH2 and inhibit IL24 transcription. Moreover, the ectopic expression of IL24 repressed cell proliferation and partly reversed LINC00152 overexpression-induced promotion of cell growth in LAD. CONCLUSIONS: Our study reveals an oncogenic role for LINC00152 in LAD tumorigenesis, suggesting that it could be used as a therapeutic target in LAD treatment.

Four alkoxohexavanadate-based Pd-polyoxovanadates as robust heterogeneous catalysts for oxidation of benzyl-alkanes.

Four alkoxohexavanadate-based Pd-POVs [Pd(dpa)(acac)]2[V6O13(OMe)6] (1), [Pd(dpa)(acac)]2[V6O11(OMe)8] (2), [Pd(dpa)(acac)]2[V6O11(OMe)8]·H2O (3), and [Pd(DMAP)2(acac)]2[V6O11(OMe)8]·H2O (4) (POV = polyoxovanadate; dpa = 2,2'-dipyridine amine; DMAP = 4-dimethylaminopyridine; acac = acetylacetone anion) have been synthesized and fully characterized by single crystal X-ray diffraction and powder X-ray diffraction analyses, Fourier transform infrared spectroscopy, element analyses, and X-ray photoelectron spectroscopy. In 1-4, Pd complexes and hexavanadate anions are assembled through electrostatic interactions. Interestingly, the [V6O11(OMe)8](2-) cores in 2 and 3 are a pair of isomers that can be isolated by controlling crystallization temperature. Moreover, to the best of our knowledge, the {V6} core in 3 represents a new octamethoxyhexavanadates cluster. It is notable that compounds 1-4 exhibit excellent heterogeneous catalytic performance in the oxidation of benzyl-alkanes with t-butylhydroperoxide as oxidant. Among them, the catalytic activity of 1 (conv. and selec. up to 99%, respectively) outperforms others and can be reused without losing its activity.

Evaluation of comprehensive environmental effect about coastal zone development activities in Liaoning Province and management advice.

Using spatial analysis function of Arcgis software, the present study investigated the building environment impact evaluation index system of coastal development in Liaoning Province. The factors of it included of current state of environmental quality, environmental impact of marine development and marine environmental disaster. Weighted factor analysis and comprehensive index method were utilized. At the end, comprehensive environment effect of coastal development in Liaoning Province were evaluated successfully. The result showed that the environmental effect of development activity were most serious, along the Zhao Jiatun coast in north of Zhimao bay and coast of Mianhua island in Dalian bay.

[The Effect of Fennel Tea Drinking on Postoperative Gut Recovery after Gynecological Malignancies Operation].

OBJECTIVE: To reveal if whether fennel fruit (Fructus Foeniculi) tea drinking enhances the recovery of intestinal function after gynecologic malignancies operation. METHODS: A total of 159 patients undergoing laparotomy for gynecological cancers were randomized into a tea group (n=78) and a control group (n=81). The patients in tea group drank a cup of fennel fruit tea while patients in control group drank the equal quantity of water twice per day from the first morning after operation until the first flatus. Every cup of tea consists of 5 gram of dried fennel fruit and 130 mL boiled water. The patents only drank the filtrate. Groups were compared in terms of time to first flatus and defecation, postoperative hospital stay, length of parenteral nutrition, ileus symptoms and other postoperative complications. RESULTS: Postoperative hospital [(5.6 +/- 1.2) d vs. (6.7 +/- 2.0) d, P<0.001], the mean time to flatus [(53.1 +/- 11.3) h vs. (64.2 +/- 13.6) h, P<0.001)], and the mean time to defecation [(4.3 +/- 1.0) d vs. (5.4 +/- 1.2) d, P < 0.001)] were significantly lower in tea group compared with those in control group. Ileus symptoms were observed more in patients in the control group compared to patients in tea group [relative risk = 2.6; 95% confidence interval, 1.5-4.5; P=0.001]. CONCLUSION: Fennel tea drinking after laparotomy for gynecological malignancis, an economical care, is safe, well to lerated and associated with rapider recovery of bowel motility, shorter hospital stay and fewer complications.

[Relationship of genotypes with clinical phenotypes and outcomes in children with cobalamin C type combined methylmalonic aciduria and homocystinuria].

OBJECTIVE: To analyze mutation types, clinical features, and treatment outcomes of cobalamin C (cblC) type combined methylmalonic aciduria and homocystinuria (MMA-HC) and to investigate the relationship of genotypes with clinical phenotypes and outcomes. METHODS: The clinical data of 16 Chinese children diagnosed with cblC type MMA-HC by gene analysis were retrospectively analyzed. According to the onset age, the patients were classified into early onset (≤1 year) and late onset (>1 year). According to the clinical phenotype, the patients were classified into mild, moderate, and severe groups. All the patients were treated with vitamin B12 (cyanocobalamin) or hydroxocobalamin, betaine, folate, vitamin B6, and L-carnitine. RESULTS: Fifteen patients belonged to the early onset type, including 11 in the severe group and 4 in the moderate group. The remaining one belonged to the late onset type. Seven reported mutations and two novel mutations (c.445_446delTG and c.349G>c) were detected. The c.609G>A and c.658_660delAAG were the most common mutations detected in 13 (81%) out of 16 patients. The genotype caused by compound heterozygous mutations of these two alleles (c.609 G>A/c.658_660delAAG) was the most common in the patients, detected in 4 (25%) out of 16 patients. Patients with this genotype had severe microcephaly and eye diseases and these clinical manifestations were not improved after the treatment. The patient with late-onset cblC type MMA-HC had normal clinical phenotypes after treatment. In the 15 early onset patients, the more severe the clinical phenotype, the worse the treatment outcome. CONCLUSIONS: The cblC type MMA-HC mainly manifests as early onset in China and c.609G >A and c.658_660delAAG are the most common mutations causing this disease. The clinical phenotypes are associated with the outcomes in children with cblC type MMA-HC.

[Clinical characteristics of pediatric hemorrhagic fever with renal syndrome].

OBJECTIVE: To study the clinical characteristics of pediatric hemorrhagic fever with renal syndrome (HFRS), and to improve its understanding so as to reduce the misdiagnosis. METHODS: A retrospective analysis was performed on the clinical data of 26 children with HFRS between January 2009 and December 2012. RESULTS: The age of disease onset was mainly distributed between 7 and 14 years (23 cases, 88%), and the male-to-female ratio was 1.89:l. The clinical manifestations of pediatric HFRS varied. The early symptoms resembled those of a cold, and in the course of HFRS, most patients developed digestive symptoms such as vomiting and abdominal pain. The laboratory examinations usually implicated platelet changes, and the imaging examinations revealed polyserous effusions. The prominent complication was myocardial injury. CONCLUSIONS: Pediatric HFRS mainly occurs in school-age children, more commonly in males. HFRS does not have typical clinical manifestations or symptoms, so it should be distinguished from cold or appendicitis at the early stage. When applying the fluid replacement therapy, the cardiac function should be carefully monitored in case of heart failure.

[Rickets-like genetic diseases].

This paper summarizes the clinical features, causative genes and treatment progress of patients with rickets-like genetic diseases, including X-linked hypophosphatemic rickets (XLH), hypophosphatasia, achondroplasia, vitamin D-dependent rickets, pycnodysostosis and ectodermal dysplasia, who visited the pediatric or child health clinic due to the symptoms of rickets, including bow legs, delayed closure of the anterior fontanelle, and sparse hair. Children with XLH usually go to hospital for bow legs and short stature, and biochemical evaluation reveals significantly low serum phosphorus so it is easily diagnosed. This disease is treated using phosphate mixture and 1,25(OH)2D3, which is different from the treatment of nutritional vitamin D deficiency rickets. Hypophosphatasia is characterized by a significant decrease in serum alkaline phosphatase, as well as normal serum calcium and phosphorus. The disease is caused by mutations in TNSALP gene. Patients with achondroplasia show short-limbed dwarfism and special face in addition to bow legs, but with normal serum calcium, phosphorus and alkaline phosphatase. Bone X-ray and FGFR3 gene test contribute to the diagnosis. Vitamin D-dependent rickets is an autosomal recessive disease, and active vitamin D supplement is effective in treatment of the disease. Patients with pycnodysostosis may be first seen at hospital because of large anterior fontanelle; in addition, they also show obtuse mandibular angle, dental abnormalities and dysplastic nails, which are caused by mutations in TSK gene. Children with ectodermal dysplasia may see a doctor for sparse hair, and they are easily misdiagnosed with nutritional vitamin D deficiency rickets. Ectodermal dysplasia is related to EDA, EDAR, EDARADD and WNT 10A genes.

[Gene mutation analysis of X-linked hypophosphatemic rickets].

OBJECTIVE: To investigate the frequency and type of PHEX gene mutations in children with X-linked hypophosphatemic rickets (XLH), the possible presence of mutational hot spots, and the relationship between genotype and clinical phenotype. METHODS: Clinical data of 10 children with XLH was retrospectively reviewed. The relationship between gene mutation type and severity of XLH was evaluated. RESULTS: PHEX gene mutations were detected in all 10 children with XLH, including 6 cases of missense mutation, 2 cases of splice site mutation, 1 case of frameshift mutation, and 1 case of nonsense mutation. Two new mutations, c.2048T>C and IVS14+1delAG, were found. The type of PHEX gene mutation was not associated with the degree of short stature and leg deformity (P=0.571 and 0.467), and the mutation site was also not associated with the degree of short stature and leg deformity (P=0.400 and 1.000). CONCLUSIONS: Missense mutation is the most common type of PHEX gene mutation in children with XLH, and c.2048T>C and IVS14+1delAG are two new PHEX gene mutations. The type and site of PHEX gene mutation are not associated with the severity of XLH.

[Clinical analysis and genetic diagnosis of short-limb inherited short stature diseases in children].

OBJECTIVE: To analyze the clinical manifestations, bone X-ray findings and genetic analysis results of three short-limb inherited short stature diseases: achondroplasia (ACH), hypochondroplasia (HCH) and pseudoachondroplasia (PSACH). METHODS: The clinical manifestations, bone X-ray findings, and genetic analysis results of 10 children with genetically confirmed short-limb inherited short stature diseases, including 4 cases of ACH 3 cases of HCH, and 3 cases of PSACH, were analyzed. RESULTS: The 10 patients had a mean body height of -3.69±1.79 SD, a mean sitting height/standing height ratio of 0.65±0.03, and a mean finger spacing/body height ratio of 0.93±0.04. Four ACH cases and 3 PSACH cases showed typical bone X-ray findings; one HCH case showed a smaller sciatic notch, and another HCH case showed no widening of interpedicular distance. G380R mutation in FGFR3 gene was detected in 3 of 4 ACH cases, and Y278C mutation in the other ACH case, N540K mutation in FGFR3 gene was detected in 3 HCH cases, and heterozygous mutations in COMP gene were detected in 3 PSACH cases. CONCLUSIONS: Children with ACH and PSACH have severer short stature and skeletal deformities than children with HCH, who have mild, atypical clinical manifestations. Bone X-ray and genetic analysis are helpful for the diagnosis and differential diagnosis of the three diseases. The mutational hotspots in two genes are involved in the three diseases, which is conducive to clinical genetic diagnosis.

Self-assembly of tripyrazolate-linked [M6L2] cages for the selective sensing of HSO3- and gaseous SO2 by turn-on fluorescence.

Owing to their structural designability and tuneable properties, supramolecular metal-organic complexes have recently emerged as promising candidates for the sensing and detection of molecules and anions. Herein, we synthesised three tripyrazolate-linked [M6L2] metallocages with the formulas [(bpyPd)6L2](NO3)6 (1), [(dmbpyPd)6L2](NO3)6 (2), and [(phenPd)6L2](NO3)6 (3) (H3L = tris(4-(5-(trifluoromethyl)-1H-pyrazol-3-yl)phenyl)amine, bpy = 2,2'-bipyridine, dmbpy = 4,4'-dimethylbipyridine, phen = 1,10-phenanthroline). Crystallography revealed that metal-directed coordination and the bidentate chelate behaviour of the ligand induced the self-assembly of supramolecular metal-organic cages. Notably, these cages were employed as turn-on fluorescence sensors for SO2 and its derivative (HSO3-) through a disassembly mechanism. Cages 1, 2, and 3 showed a highly selective and sensitive detection of HSO3- over other common anions in aqueous solutions and of SO2 gas over other common gasses, with an excellent anti-interference ability. These metallocages were subsequently applied as sensors in environmental and biological samples. This study not only enriches the ongoing research on metal-organic supramolecular materials but also facilitates the future preparation of stimuli-responsive supramolecular coordination complexes.

Correction: Self-assembly of tripyrazolate-linked [M6L2] cages for the selective sensing of HSO3- and gaseous SO2 by turn-on fluorescence.

Correction for 'Self-assembly of tripyrazolate-linked [M6L2] cages for the selective sensing of HSO3- and gaseous SO2 by turn-on fluorescence' by Peipei Wang et al., Dalton Trans., 2023, https://doi.org/10.1039/d3dt00083d.

[Molecular genetics of functional articulation disorder in children].

Genetic factors are an important cause of functional articulation disorder in children. This article reviews some genes and chromosome regions associated with a genetic susceptibility to functional articulation disorders. The forkhead box P2 (FOXP2) gene on chromosome 7 is introduced in details including its structure, expression and function. The relationship between the FOXP2 gene and developmental apraxia of speech is discussed. As a transcription factor, FOXP2 gene regulates the expression of many genes. CNTNAP2 as an important target gene of FOXP2 is a key gene influencing language development. Functional articulation disorder may be developed to dyslexia, therefore some candidate regions and genes related to dyslexia, such as 3p12-13, 15q11-21, 6p22 and 1p34-36, are also introduced. ROBO1 gene in 3p12.3, ZNF280D gene, TCF12 gene, EKN1 gene in 15q21, and KIAA0319 gene in 6p22 have been candidate genes for the study of functional articulation disorder.

[Clinical application of M-CHAT and CHAT-23 for autism screening].

OBJECTIVE: To analyze and compare Modified Checklist for Autism in Toddlers (M-CHAT) and Checklist for Autism in Toddlers-23 (CHAT-23) in terms of clinical applicability, and to provide a basis for the understanding of early specific clinical manifestations of children with autism. METHODS: A total of 350 children aged 18-36 months who visited the Department of Developmental Pediatrics of Shengjing Hospital of China Medical University were enrolled as subjects. Of the 350 children, 284 who had not been previously diagnosed with autism were screened according to the two checklists. Sixty-eight confirmed cases of autism (including two of the 284 screening subjects diagnosed with autism) were assigned to the autism group, and 278 of the 284 screening subjects (except six children diagnosed with autism, mental retardation or cerebral palsy) were assigned to the control group. The two groups were compared with respect to the positive rate for each item in the checklists. The efficacy of the M-CHAT and CHAT-23 assessment criteria was evaluated by comparative analysis. RESULTS: The autism group showed the highest positive rate for Item 9. There were significant differences between the two groups in terms of the positive rates for all items except Item 16 (P<0.05). When the assessment criterion was that autism was confirmed if there were positive results for at least 3 of a total of 23 items, M-CHAT showed the lowest rate of missed diagnosis (0%); when the assessment criterion was that autism was confirmed if there were positive results for at least 6 of a total of 23 items, CHAT-23 showed the lowest rate of misdiagnosis (1.77%). The specificity of M-CHAT is lower than that of CHAT-23 (P<0.05). There was no significant difference in sensitivity between the two checklists (P>0.05). CONCLUSIONS: CHAT-23 is more suitable than M-CHAT for clinical autism screening due to higher specificity, as well as having the advantages of low cost, easy completion,high efficiency and easy result judgment.

Novel compound heterozygous variants in the TAF6 gene in a patient with Alazami-Yuan syndrome: A case report.

BACKGROUND: This case report describes a novel genotypic and phenotypic presentation of Alazami-Yuan syndrome, and contributes to the current knowledge on the condition. CASE SUMMARY: We report an 11-year-old boy with Alazami-Yuan syndrome. The main clinical manifestations were rapid development of puberty, typical facial features of Cornelia de Lange syndrome, and normal intelligence. Peripheral blood DNA samples obtained from the patient and his parents were sequenced using high-throughput whole-exosome sequencing, which was verified by Sanger sequencing. The results showed that there was a compound heterozygous mutation of c.1052delT and c.76A>T in the TATA-Box Binding Protein Associated Factor 6 (TAF6) gene. The mutation of c.1052delT was from his mother and the mutation of c.76A>T was from his father. CONCLUSION: This study extends the mutation spectrum of the TAF6 gene, and provides a molecular basis for the etiological diagnosis of Alazami-Yuan syndrome and genetic consultation for the family.

hsBAFF regulates proliferation and response in cultured CD4(+) T lymphocytes by upregulation of intracellular free Ca(2+) homeostasis.

B cell activating factor belonging to the TNF family (BAFF, also called BLyS, TALL-1, THANK, or zTNF4) is an important survival factor for B cells, and is able to regulate T-cell activation. Recently, we have demonstrated that treatment of mice with human soluble BAFF (hsBAFF) causes a significant increase of percentages of splenic CD4(+) T lymphocytes dose-dependently, but the CD8(+) T lymphocyte percentages maintained unchanged. Here, we show that hsBAFF significantly enhanced CD4(+) T lymphocyte response of cultured mouse splenic cells, and hsBAFF induced the proliferation and IL-2/IFN-γ secretion of purified CD4(+) T lymphocytes suboptimally stimulated through anti-CD3. Of importance, we observed that IL-2 or IFN-γ cytokine has additive effect on the proliferation and activity of hsBAFF-stimulated CD4(+) T lymphocytes. Using Flow cytometry with fluorescent probe, Fluo-3/AM, we found that hsBAFF elicited [Ca(2+)](i) elevation contributing to CD4(+) T cell proliferation. This is evidenced by our finding that pretreatment with BAPTA/AM, an intracellular Ca(2+) chelator, significantly attenuated the proliferation of hsBAFF-stimulated CD4(+) T lymphocytes. Subsequently, we revealed that hsBAFF-stimulated CD4(+) T cell proliferation was markedly suppressed after pretreatment with EGTA, an extracellular Ca(2+) chelator, or with 2-APB, an inhibitor of Ca(2+) influx through CRAC channels, respectively, suggesting that extracellular Ca(2+) influx due to hsBAFF is closely associated with [Ca(2+)](i) elevation contributing to CD4(+) T cell proliferation. In addition, we noticed that hsBAFF-treated cells conferred partial resistance to decrease of cellular viability induced by thapsigargin (Tg), an endoplasmic reticulum (ER) Ca(2+)-ATPase inhibitor. Taken together, our data indicate that hsBAFF may promote CD4(+) T cell proliferation and response by upregulation of [Ca(2+)](i) homeostasis.

[Relationship between gene mutations and intelligence in children with Duchenne muscular dystrophy].

OBJECTIVE: To study the level of intelligence in children with Duchenne muscular dystrophy (DMD), and the relationship between the level of intelligence and gene mutations. METHODS: One hundred and two children with DMD between January 2009 and March 2011 were enrolled. DMD gene detection was performed through the multiplex ligation-dependent probe amplification (MLPA) in 84 cases. The level and the structure of intelligence were evaluated by Chinese Wechsler Intelligence Scale for Children (C-WISC) in 50 children with DMD (≥6 years old; DMD group) and in 50 age-and gender-matched healthy children (control group). RESULTS: The average intelligence quotient (IQ) was 84±21 in 102 children with DMD. Thirty patients (29.4%) had the full intelligence quotient (FIQ) less than 70. The FIQ, verbal intelligence quotient (VIQ), performance intelligence quotient (PIQ) and the scores of 11 sub-tests of intelligence in the DMD group were significantly lower than those in the control group (P<0.01). The IQ in patients with gene mutations at exon 56-79 was the lowest (59.3±11.9), followed by in patients with gene mutations at exon 45-55 (88.6±1.9), at exon 1-29 (97.5±9.6) and at exon 30-44 (102.8±3.8) (P<0.01). CONCLUSIONS: The FIQ, VIQ and PIQ in children with DMD are lower than those in healthy children. There is association between mental retardation and gene mutations.

[Study of SMN gene in Chinese children with spinal muscular atrophy].

OBJECTIVE: To study the incidence of homozygous absence of SMN1 exons 7 and 8, SMN gene conversion frequency and SMN subtle mutations in children with spinal muscular atrophy (SMA). METHODS: The homozygous deletion was detected by PCR-RFLP in 106 Chinese children with SMA, gene conversion by RFLP and subtle mutations by sequencing. RESULTS: The rate of deletion of SMN1 exons 7 and/or 8 was 91.5%. Deletion of SMN1 exon 8 but existence of exon 7 was noted in one child with SMA. There were no significant differences in the gene conversion frequency among children with different types of SMA and who had homozygous deletion of SMN1 exon 7 but existence of exon 8. The gene conversion frequency was 8.3% in children with homozygous deletion of SMN1 exon 7. No subtle mutations were found around SMN1 exon 7. CONCLUSIONS: Deletion of SMN1 exons 7 and/or 8 is the main cause of SMA in Chinese children. There exists a SMN gene conversion phenomenon in SMA. Deletion of exon 8 might lead to SMA. The hot area of subtle mutations of this disease might not be around SMN1 exon 7.