CD36 gene deletion reduces muscle insulin sensitivity in mice by up-regulating PTP1B expression / 南方医科大学学报

OBJECTIVE@#To investigate the effect CD36 deficiency on muscle insulin signaling in mice fed a normal-fat diet and explore the possible mechanism.@*METHODS@#Wild-type (WT) mice and systemic CD36 knockout (CD36-/-) mice with normal feeding for 14 weeks (n=12) were subjected to insulin tolerance test (ITT) after intraperitoneal injection with insulin (1 U/kg). Real-time PCR was used to detect the mRNA expressions of insulin receptor (IR), insulin receptor substrate 1/2 (IRS1/2) and protein tyrosine phosphatase 1B (PTP1B), and Western blotting was performed to detect the protein expressions of AKT, IR, IRS1/2 and PTP1B in the muscle tissues of the mice. Tyrosine phosphorylation of IR and IRS1 and histone acetylation of PTP1B promoter in muscle tissues were detected using co-immunoprecipitation (Co-IP) and chromatin immunoprecipitation (ChIP), respectively.@*RESULTS@#CD36-/- mice showed significantly lowered insulin sensitivity with obviously decreased area under the insulin tolerance curve in comparison with the WT mice (P < 0.05). CD36-/- mice also had significantly higher serum insulin concentration and HOMA-IR than WT mice (P < 0.05). Western blotting showed that the p-AKT/AKT ratio in the muscle tissues was significantly decreased in CD36-/- mice as compared with the WT mice (P < 0.01). No significant differences were found in mRNA and protein levels of IR, IRS1 and IRS2 in the muscle tissues between WT and CD36-/- mice (P>0.05). In the muscle tissue of CD36-/- mice, tyrosine phosphorylation levels of IR and IRS1 were significantly decreased (P < 0.05), and the mRNA and protein levels of PTP1B (P < 0.05) and histone acetylation level of PTP1B promoters (P < 0.01) were significantly increased as compared with those in the WT mice. Intraperitoneal injection of claramine, a PTP1B inhibitor, effectively improved the impairment of insulin sensitivity in CD36-/- mice.@*CONCLUSION@#CD36 is essential for maintaining muscle insulin sensitivity under physiological conditions, and CD36 gene deletion in mice causes impaired insulin sensitivity by up-regulating muscle PTP1B expression, which results in detyrosine phosphorylation of IR and IRS1.

Construction of spvD gene deletion mutant and compensation strains in Salmonella enteritidis and its effects on Caco-2 cells / 中华预防医学杂志

Objective: To analyze the effects of spvD gene on invasion and intracellular proliferation of Caco-2 cells and in order to provide insight into the function of that gene and the underlying mechanism of Salmonella caused infection. Methods: Functional verification of spvD gene deletion mutant and compensation strain. The deletion mutant strain was constructed through a suicide plasmid-mediated homologous recombination. The compensation plasmid constructed by cloning the coding sequence of spvD by PCR into plasmid pBAD33 was mobilized into the deletion mutant by conjugation and the pBAD33 was introduced into wild strains and deleted mutant strains as control. The relative expression of spvD mRNA was detected by quantitative reverse transcription PCR. In order to analyze the virulence of spvD against Caco-2 cells, Caco-2 cells was cocultured with wild type Salmonella enteritidis carrying spvD gene, the deletion mutant strain and compensation strain respectively. The expression level of spvD mRNA and the the number of Salmonella enteritidis after Caco-2 cells intervention were compared between the three groups by LSD-t test, and the invasion rate was compared by χ2 test. Results: The expression level of spvD mRNA in wild type Salmonella enteritidis was set as unit "1", the deletion mutant strain was "0.00", and the compensation strain was "2.60" (LSD-twild, deleted=1.11, P=0.31; LSD-twild, compensation=-1.77, P=0.13; LSD-t deleted, compensation=-2.88, P=0.03), which confirmed the successful construction of the deletion mutant strain and the compensation strain. The invasion experiment results of the above three Salmonella enteritidis strains on Caco-2 cells showed that the invasion rate of wild strain was 0.23%, the invasion rate of deleted mutant strain was 0.16%, and the invasion rate of compensation strain was 0.16%, with no statistical significance (χ2=1.13, P=0.570). By comparing the number of Salmonella enteritidis at different time points after Caco-2 cells intervention, it was discovered that the number of Salmonella enteritidis in wild strains (6.50×106 CFU/ml) and compensation strains (7.25×106 CFU/ml) was significantly increased than that in deletion mutant strain (1.90×106 CFU/ml) after 16 h coculture (LSD-twild, deleted=7.95, P=0.00; LSD-twild, compensation=-1.27, P=0.25; LSD-t deleted, compensation=-9.22, P=0.00). Conclusion: It is not considered that spvD gene can affect the invasion of Salmonella enteritidis on Caco-2 cells, but the gene can promote the reproduction of Salmonella enteritidis in Caco-2 cells.

Prognostic significance of IKZF1 gene deletions in patients with B-cell acute lymphoblastic leukemia / 中华血液学杂志

Objective: This study aimed to investigate the prognostic significance of IKZF1 gene deletion in patients with acute B lymphoblastic leukemia (B-ALL) . Methods: The clinical data of 142 patients with B-ALL diagnosed in Nanfang Hospital between March 2016 and September 2019 were analyzed. Results: IKZF1 deletion was found in 36.0% of the 142 patients with B-ALL, whereas exon 4-7 deletion was found in 44.0% . White blood cell counts were higher in patients with the IKZF1 deletion (52.0% and 28.3% , P=0.005) ; these patients also experienced worse effects of mid-term induction therapy (40.0% and 70.7% , P<0.001) and had a higher proportion of Philadelphia chromosome-positive (52.0% and 21.7% , respectively, P<0.001) . Univariate analysis revealed that the 3-year overall survival rate (OS) and event-free survival rate (EFS) in the IKZF1 deletion group were significantly lower than the IKZF1 wild-type group [ (37.1±7.3) % vs (54.7±5.4) % , (51.8±7.9) % vs (73.9±4.7) % ; P=0.025, 0.013, respectively]. Multivariable analysis showed that harboring IKZF1 deletion was an adverse factor of EFS and OS (HR=1.744, 2.036; P=0.022, 0.020, respectively) . Furthermore, the IKZF1 deletion/chemotherapy group had significantly lower 3-year OS, EFS, and disease-free survival rates than other subgroups. In the IKZF1 deletion cohort, allo-hematopoietic stem cell transplantation (HSCT) significantly improved OS and EFS compared to non-allo-HSCT[ (67.9±10.4) % vs (31.9±11.0) % , (46.6±10.5) % vs (26.7±9.7) % ; P=0.005, 0.026, respectively]. Conclusion: Pediatric-inspired chemotherapy was unable to completely reverse the negative effect of IKZF1 deletion on prognosis. Pediatric-inspired regimen therapy combined with allo-HSCT, in contrast, significantly improved the overall prognosis of IKZF1 deletion B-ALL.

Síndrome da deleção 2q37.3 ­ A primeira descrição de achados orais, relato de caso / 2q37.3 delection syndrome ­ The first description of oral phenotype, a case repor

Introdução: A síndrome de deleção 2q37.3 é uma desordem causada pela microdeleção de uma subbanda no cromossomo 2, cuja epidemiologia é de aproximadamente 150 casos no mundo, e a incidência de 1:10000. As características da síndrome são: atraso no desenvolvimento, dismorfia facial, anormalidades musculoesqueléticas e aumento ao risco de doenças congênitas. O objetivo deste relato de caso é apresentar, pela primeira vez na literatura, os achados clínicos orais e dentários associados à síndrome. Relato de caso: As principais características físicas da síndrome foram identificadas na paciente durante o exame físico: lábio superior fino, columela proeminente e dobras epicânticas. No exame intraoral, relatou-se as características odontológicas, que podem estar associadas à síndrome: acúmulo de cálculo dental, hipomineralização e hipoplasia, mordida cruzada, mordida aberta, agenesias, taurodontia e cisto dentígero. O tratamento dental consistiu na aplicação de técnicas de manejo de comportamento, instrução de higiene oral e de dieta, profilaxia, raspagem supragengival, aplicação tópica de flúor, além da extração do segundo molar decíduo inferior. Este é o primeiro relato de características orais da síndrome de deleção 2q37.3 dando importância às características observadas nesta paciente. Tais achados também serão úteis na caracterização da síndrome, que é extremamente rara, podendo contribuir para o diagnóstico clínico desses pacientes, além de subsidiar o tratamento odontológico de outros indivíduos. Conclusão: Apresentamos os achados clínicos orais como hipomineralização e hipoplasia, mordida cruzada e aberta, agenesia, taurodontia e cisto dentígero presentes na paciente com a síndrome e sugerimos que o gene envolvido ou sua deleção possam ser responsáveis por tais achados.

Introduction: The 2q37.3 deletion syndrome is a disorder caused by the microdeletion of a subband on chromo-some 2, whose epidemiology is approximately 150 cases worldwide, and the prevalence of 1:10000. Its charac-teristics are developmental delay, facial dysmorphia, musculoskeletal abnormalities, and increased risk of congenital diseases. The purpose is to present, for the first time in the literature, the oral and dental clinical findings associated with the syndrome. Case report: The main physical characteristics of the syndrome were identified during the physical examination: thin upper lip, prominent columella, and epicanthic folds. In the intraoral examination, dental characteristics were reported, which may be associated with the syndrome: accumulation of dental calculus, hypomineralization and hypoplasia, crossbite, open bite, agenesis, taurodontism, and dentigerous cyst. The dental treatment consisted of the application of behavior management techniques, oral hygiene and diet instruction, prophylaxis, supragingival scraping, topical fluoride application, and extraction of the lower second molar. This is the first report of oral characteristics of the 2q37.3 deletion syndrome, giving importance to the characteristics observed in this patient. Such findings will be useful in the characterization of the syndrome, which is extremely rare, and may contribute to the clinical diagnosis of these patients, in addition to subsidizing the dental treatment of other individu-als. Conclusion: We present oral clinical findings such as hypomineralization and hypoplasia, crossed and an open bite, agenesis, taurodontism, and dentigerous cyst present in the patient with the syndrome and we suggest that the involved gene or its deletion may be responsible for such findings.

Diagnosis of a patient with adjacent gene deletion syndrome with DMD complete deletion type of Duchenne muscular dystrophy / 中华医学遗传学杂志

OBJECTIVE@#To identify the etiology of a patient with severe symptoms of DMD and to trace its pathogenic gene, so as to provide a basis for genetic counseling and clinical intervention.@*METHODS@#Multiple ligation-dependent probe amplification (MLPA) technique was used to analyze exon deletion/repetitive variant of DMD gene, and further analysis was performed by chromosome G-banding, fluorescence in situ hybridization (FISH) and SNP array analysis.@*RESULTS@#The MLPA results of the proband showed that the exon 1-79 of DMD gene were deleted, the G-banding karyotype of blood sample was 46, XY, and the deletion of the short arm of X chromosome was found by FISH. SNP array results showed that 5.8Mb (29 628 158-35 434 714) deletion occurred in the Xp21.2p21.1 region of X chromosome, and the patient was diagnosed as the contiguous deletion syndrome involving the genes of IL1RAPL, MAGEB1-4, ROB, CXorf2, GM, AP3K7IP, FTHL1, DMD, FAM47A, TMEM47, and FAM47B.@*CONCLUSION@#The exact pathogenic site of this family is the deletion of 5.8 Mb (29 628 158-35 434 714) in the Xp21.2p21.1 region of X chromosome, which can be used for prenatal diagnosis. High resolution SNP array technique plays an important role in detecting potential chromosome abnormalities in patients.

Variant analysis and therapeutic prospect for Chinese pedigrees affected with Duchenne/Becker muscular dystrophy from a single center over the past 15 years / 中华医学遗传学杂志

OBJECTIVE@#To summarize the result of genetic testing and therapeutic prospect of 2042 unrelated Chinese pedigrees affected with Duchenne/Becker muscular dystrophy (DMD/BMD) from a single center from 2005 to 2019.@*METHODS@#Peripheral blood samples of the pedigrees were collected for the detection of DMD gene variants with combined multiple ligation-dependent probe amplification (MLPA), next generation sequencing (NGS) and Sanger sequencing.@*RESULTS@#DMD and BMD have respectively accounted for 78.60% and 21.40% of the pedigrees, which included 33 female probands. Variants of the DMD gene were detected in 1986 pedigrees (97.26%). Large deletions, duplications and small-scale mutations have respectively accounted for 71.85%, 8.76% and 19.39%. Common deletions and duplications have included deletion of exons 45-50 and duplications of exon 2, while no hot spot was found with small-scale mutations. For 1595 pedigrees affected with DMD, 935 (58.62%) were hereditary and 660 (41.38%) were de novo in origin. 34.28% (700/2042) of the patients had symptoms which could be relieved by gene therapy.@*CONCLUSION@#This has been the largest single-center study of DMD pedigrees, which has attained definite diagnosis in 97.26% of the patients. The results have enabled genetic counseling and prenatal diagnosis for the affected families upon their subsequent pregnancies, enriched the spectrum of DMD gene variants, as well as facilitated study of the mechanism of DMD gene mutations and exploration of clinical treatment.

Improvement of polyhydroxybutyrate production by deletion of csrA in Escherichia coli

BACKGROUND: Poly-3-hydroxybutyrate (PHB) can be efficiently produced in recombinant Escherichia coli by the overexpression of an operon (NphaCAB) encoding PHB synthetase. Strain improvement is considered to be one of critical factors to lower the production cost of PHB in recombinant system. In this study, one of key regulators that affect the cell growth and PHB content was confirmed and analyzed. RESULT: S17-3, a mutant E. coli strain derived from S17-1, was found to be able to achieve high cell density when expressing NphaCAB with the plasmid pBhya-CAB. Whole genome sequencing of S17-3 revealed genetic alternations on the upstream regions of csrA, encoding a global regulator cross-talking between stress response, catabolite repression and other metabolic activities. Deletion of csrA or expression of mutant csrA resulted in improved cell density and PHB content. CONCLUSION: The impact of gene deletion of csrA was determined, dysfunction of the regulators improved the cell density of recombinant E. coli and PHB production, however, the detail mechanism needs to be further clarified.

A predictive analysis of the association between clinical phenotypes and genotypes in children with Becker muscular dystrophy/Duchenne muscular dystrophy / 中国当代儿科杂志

OBJECTIVE@#To study the association between clinical phenotypes and genotypes in children with Becker muscular dystrophy (BMD)/Duchenne muscular dystrophy (DMD) so as to provide a theoretical basis for disease management, gene therapy, and prenatal diagnosis.@*METHODS@#A retrospective analysis was performed for the clinical data and gene detection results of 52 children with BMD/DMD. Multiplex ligation-dependent probe amplification (MLPA) was used to detect the DMD gene. The children with negative results of MLPA were further screened by exon chip capture combined with next-generation sequencing (NGS). The mothers of 20 probands were validated by sequencing.@*RESULTS@#The pathogenic genes for BMD/DMD were detected in 50 children by MLPA and NGS, with a detection rate of 96%. Among the 52 children, 36 (69%) had gene deletion, 7 (13%) had duplication, and 7 (13%) had micromutation. Among the 43 children with deletion/duplication, 32 had DMD and 11 had BMD; 37 children (86%) met the reading frame rule, among whom 27 (96%) had DMD and 10 (67%) had BMD. All 7 children with micromutation had DMD.@*CONCLUSIONS@#The reading frame rule has an extremely high predictive value for DMD but a limited predictive value for BMD.

Analysis of (DPY19L2 gene variant in two brothers affected with globozoospermia / 中华医学遗传学杂志

OBJECTIVE@#To explore the molecular basis for two brothers affected with globozoospermia.@*METHODS@#Whole exome sequencing was carried out for both patients. Candidate variant was verified by Sanger sequencing and quantitative real-time PCR (qRT-PCR).@*RESULTS@#Whole exome sequencing, Sanger sequencing and qRT-PCR verification revealed a heterozygous c.384dup (p.Glu129*) variant in the DPY19L2 gene in the two brothers and their mother. A large heterozygous deletion, spanning approximately 164.5 kb and encompassing the entire DPY19L2 gene, was detected on chromosome 12 of the two patients and their father.@*CONCLUSION@#The c.384dup (p.Glu129*) variant and deletion of the DPY19L2 gene probably underlie the pathogenesis of globozoospermia in the two patients, which was in keeping with the autosomal recessive inheritance of disease in this pedigree.

The secreted acid trehalase encoded by the CgATH1 gene is involved in Candida glabrata virulence

BACKGROUND Candida glabrata yeast is the second cause of candidiasis worldwide. Differs from other yeasts since assimilates only glucose and trehalose (a characteristic used in rapid identification tests for this pathogen) by secreting into the medium a highly active acid trehalase encoded by the CgATH1 gene. OBJECTIVE This study aimed to characterise the function of the acid trehalase in the physiopathology of C. glabrata. METHODS Gene deletion was performed to obtain a mutant ath1Δ strain, and the ability of the ath1Δ strain to grow in trehalase, or the presence of trehalase activity in the ath1Δ yeast cells, was verified. We also tested the virulence of the ath1Δ strain in a murine model of infection. FINDINGS The ath1Δ mutant strain grows normally in the presence of glucose, but loses its ability to grow in trehalose. Due to the high acid trehalase activity present in wild-type cells, the cytoplasmic neutral trehalase activity is only detected in the ath1Δ strain. We also observed a significantly lower virulence of the ath1Δ strain in a murine model of infection with either normal or immunocompromised mice. MAIN CONCLUSIONS The acid trehalase is involved in the hydrolysis of external trehalose by C. glabrata, and the enzyme also plays a major virulence role during infectivity.

Detection of BCR/ABL Fusion Gene and ASS1 Gene Deletion by Using Tricolor Dual-fusion Probe / 中国实验血液学杂志

OBJECTIVE@#To analyze the significance of various abnormal signal patterns appreared in CML and B-ALL patients by using BCR/ABL/ASS1 tricolor dual-fusion probe, and to explore its application value in detecting BCR/ABL fusion gene and ASS1 gene deletion.@*METHODS@#50 newly diagnosed CML patients and 50 newly diagnosed B-ALL patients were detected by fluorescence in situ hybridization (FISH) with BCR/ABL/ASS1 tricolor dual-fusion probe. Meanwhile, karyotype analysis was performed on all the patients using the 24 hours short-term culture and R-banding.@*RESULTS@#Among the 50 CML patients, Ph was found in 49 cases, 5 normal interphase karyotype was observed in 1 case. FISH detection showed that BCR/ABL fusion gene existed in all patients (100%), while the positive signal pathway showed that 1R1G2B2F was observed in 39 cases (78%), 2R1G2B1F in 2 cases (4%) and 1R1G2B1F in 6 cases (12%), simultaneous existence of 1R1G1B1F and 1R1G2B3F in 1 case (2%), 2R1G1B1F in 1 case (2%) 1R1G3B3F in 1 case (2%). FISH detection also showed that the karyotype of 6 case at ASS1 gene deletion (1R1G1B1F) all were simple t (9; 22) translocation, and other abnormalities not were observed. Among 50 cases of B-ALL, Ph was found in 13 cases, the numerical aberration and structural aberration of non t (9; 22) in 16 cases, normal karyotype in 20 cases, absence of mitotic phase in 1 case. FISH detection showed that 16 cases (32%) had BCR/ABL fusion gene including 13 cases (26%) of 1R1G2B2F, 1 case (2%) of stimultaneous exitance of 1R1G2B2F and 1R1G3B3F 1 case (2%) of 2R1G1B1F, 1 case (2%) of 1R1G3B2F. FISH detection also showed that 3 cases had BCR/ABL fusion gene, including 1 case with ASS1 gene deletion (2R1G1B1F), 1 case with classical t (9; 22) translocation (1R1G2B2F) and 1 case with BCR/ABL fusion gene and increase of ASS1 gene copy (1R1G3B3F).@*CONCLUSION@#Tricolor dual-fusion FISH probe for detecting BCR/ABL fusion gene and ASS1 gene deletion is simple, rapid, sensitive and stable. It can detect various forms of molecular fusion and avoid the false positive results due to coincidental overlap of signals generated by D-FISH probe and ES-FISH probe. In addition, this detection method not only can directly observe the presence or absence of ASS1 gene deletion, but also improve the reliability of the positive results of newly diagnosed BCR/ABL fusion gene and accuracy of monitoring results of minimal residual disease for the subsequent visit.

Genetic analysis of a child with atypical Williams-Beuren syndrome presenting as supravalvular aortic stenosis / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child with supravalvular aortic stenosis.@*METHODS@#The child and his parents were subjected to conventional G-banding karyotyping, array comparative genomic hybridization (aCGH) and multiplex ligation-dependent probe amplification (MLPA) analysis.@*RESULTS@#No karyotypic abnormality was detected in the child and his parents. aCGH has identified a de novo 278 kb deletion encompassing the ELN gene in 7q11.23, which overlapped with the critical region of Williams-Beuren syndrome (WBS). MLPA has confirmed above findings.@*CONCLUSION@#The proband was diagnosed with atypical WBS. Deletion of the ELN gene may predispose to supravalvular aortic stenosis in the proband.

Diagnosis and clinical phenotype analysis of a case with large fragment homozygous deletion of rare β gene cluster / 中华医学遗传学杂志

OBJECTIVE@#To report on a case with homozygous deletion of large β gene cluster and its clinical characteristics.@*METHODS@#A total of 71 001 peripheral blood samples were subjected to capillary electrophoresis and conventional testing for common thalassemia mutations. The genotypes of suspected β gene cluster deletions were analyzed by Gap-PCR and multiplex ligation-dependent probe amplification (MLPA). Their hematological characteristics were compared by statistical analysis R software.@*RESULTS@#Eighty-nine cases were detected with Chinese @*CONCLUSION@#The carrier rate for large fragment deletions of β gene cluster in Huizhou region is rather high, for which the value of HbF is significantly increased. Attention should be paid to screening and diagnosis of rare genotype to prevent missed diagnosis and/or misdiagnosis.

Role of genetic variability in Mendelian and multifactorial diseases

The first draft of the human genome sequencing published in 2001 reported a large number of single nucleotide polymorphisms (SNPs). Given that these polymorphisms could practically represent all the variability involved in the susceptibility, protection, severity, among other aspects, of various common diseases, as well as in their response to medications, it was thought that they might be “the biomarkers of choice” in personalized genomic medicine. With the new information obtained from the sequencing of a larger number of genomes, we have understood that SNPs are only an important part of the genetic markers involved in these traits. In addition to SNPs, other variants have been identified, such as insertions/deletions (INDELs) and copy number variants (CNVs), which – in addition to classic variable number tandem repeats (VNTRs) and short tandem repeats (STRs) – originate or contribute to the development of diseases. The use of these markers has served to identify regions of the genome involved in Mendelian diseases (one gene-one disease) or genes directly associated with multifactorial diseases. This review has the purpose to describe the role of STRs, VNTRs, SNPs, CNVs and INDELs in linkage and association studies and their role in Mendelian and multifactorial diseases.

Searching for mutations in the HNF1B gene in a Brazilian cohort with renal cysts and hyperglycemia

ABSTRACT Objective To verify the presence of variants in HNF1B in a sample of the Brazilian population selected according to the presence of renal cysts associated with hyperglycemia. Subjects and methods We evaluated 28 unrelated patients with clinical suspicion of HNF1B mutation because of the concomitant presence of diabetes mellitus (DM) or prediabetes and renal cysts. Genotyping was accomplished using Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA). In positive cases, available relatives were recruited. Results We found two patients with HNF1B mutations. The first presented the variant p.Pro328Leufs*48(c.983delC) and had DM, renal cysts, and hypomagnesemia. The second presented a heterozygous whole gene deletion in HNF1B, DM, renal cysts, body and tail pancreatic agenesis, and hypomagnesemia; this alteration was also found in his two siblings and his father. Conclusion The recruitment of suspected cases of HNF1B gene mutations in Brazilians due to hyperglycemia and renal cysts presents two positive cases. Our cases contribute to the annotation of clinical and biochemical phenotypes of this rare form of maturity-onset diabetes of the young (MODY).

Síndrome de Rett: Análisis molecular del gen MECP2 en pacientes chilenas / Rett syndrome: MECP2 gene molecular analysis in Chilean patients

INTRODUCCIÓN: El síndrome de Rett (RTT) es un trastorno neurológico progresivo caracterizado por producir una regresión del desarrollo psicomotor en niñas previamente sanas. La mayoría de los casos son causados por variantes patogénicas en el gen MECP2, que codifica para la proteína methyl CpG- binding protein 2. OBJETIVO: Describir la frecuencia y el tipo de variantes patogénicas en MECP2 en mujeres chilenas con diagnóstico clínico de RTT. PACIENTES Y MÉTODO: Se invitó a participar en este estudio a mujeres chilenas con sospecha clínica de RTT. Se reunió información clínica mediante un cuestionario. Se analizaron variantes patogénicas en MECP2 mediante el método de secuenciación de Sanger y se utilizó Multiple Ligation-dependant Probe Amplification (MLPA) para la detección de duplicaciones y deleciones. RESULTADO: El estudio incluyó 14 pacientes con sospecha de RTT, de las cuales 8 (57%) pacientes tuvieron variantes patogénicas. Las restantes permanecen sin diagnóstico molecular. CONCLUSIÓN: Variantes patogénicas en MECP2 están presentes en pacientes chilenas con RTT. Es probable que haya otros genes o diagnósticos involucrados en las pacientes sin hallazgos en MECP2. A partir de este trabajo, el diagnóstico molecular está disponible en Chile.

INTRODUCTION: Rett syndrome (RTT) is a progressive neurological disorder characterized by regres sion of psychomotor development in previously healthy girls. Most cases are due to pathogenic va riants in the MECP2 gene which encodes for the methyl CpG-binding protein 2. OBJECTIVE: To des cribe the frequency and type of pathogenic variants in the MECP2 gene in Chilean female patients with clinical diagnosis of RTT. PATIENTS AND METHOD: Chilean women with clinical suspicion of RTT were invited to participate in the study. Clinical data were collected through a questionnaire. MECP2 pathogenic variants were analyzed by Sanger sequencing method and Multiplex Ligation-dependent Probe Amplification (MLPA) was used to detect duplications or deletions. RESULTS: The study in cluded 14 patients with suspected RTT, of which eight (57%) patients had pathogenic variants. The other patients remain without molecular diagnosis. CONCLUSIONS: Pathogenic variants in MECP2 are present in Chilean patients with RTT. It is likely that there are other genes or diagnoses involved in patients without MECP2 findings. As of this study, molecular diagnosis is available in Chile.

BAX Gene Deletion Reduces the Sensitivity of BCR-ABL-Induced B-ALL Cells of Mice to Imatinib / 中国实验血液学杂志

OBJECTIVE@#To investigate the effect of BAX gene deletion on the sensitivity of BCR-ABL-induced B-ALL cells of mice to imatinib and the related mechanism.@*METHODS@#The target gene-knock out (BAX) mice were used as bone marrow cell donors; the wild type bone marrow cells(B6BM) and BAX bone marrow cells(B6BM-BAX) of mice were transfected by using reverse transcription virus, then the BCR-ABL transfected B6BM cells and B6BM-BAX cells were treated with imatinib at different concentration (0,0.5, 1.0 and 2.0 μmol/L) for 48 hours. The number of viable cells was detected by trypan blue, the flow cytometry was used to detect the cell apoptosis, the Western blot was used to detect the changes of BAX, Caspase expression.@*RESULTS@#In BCR-ABL transfected bone marrow cells treated with imatinib, the numbers of viable cells of BAX deletion group was significantly higher than that of wild type groups with statristcal difference(P<0.05), and effect- and dose-dependency(r=-0.9533 for BAX deletion group, and r=-0.9812 for wild type group). The flow cytometry showed that the cell apoptosis in BAX deletion group signifincantly decreased, compared with wild type group(P<0.05). The Western blot showed that the expression of apoptotic protein Caspase 3 in BAX deletion group was significantly higher than that in wild type group(P<0.05).@*CONCLUSION@#BAX deletion can reduce the sensitivity of BCR-ABL-induced B-ALL cells to imatinib.

Incidental discovery of DMD gene deletions by chromosomal microarray analysis / 中华医学遗传学杂志

OBJECTIVE@#To discuss the value of chromosomal microarray analysis (CMA) for the identification of DMD gene deletions during prenatal diagnosis.@*METHODS@#G-banded karyotyping and CMA were performed on fetuses with ultrasonographic soft markers but no family history for Duchenne/Becker muscular dystrophy (DMD/BMD). Denaturing high-performance liquid chromatograghy (DHPLC) was used to detect DMD gene mutations in umbilical cord blood and peripheral blood samples from the mothers.@*RESULTS@#For fetus 1, analysis of amniocytes showed a normal karyotype, while CMA detected a 119 kb deletion at Xp21.1 (32 565 489 - 32 681 461), which encompassed exons 10 to 16 of the DMD gene. The result was confirmed by DHPLC analysis. The mother was found to have loss of heterozygosity in the same region. For fetus 2, karyotyping of amniocytes also showed a normal male karyotype, while CMA detected a 254 kb deletion at Xp21.1 (32 104 604 - 32 358 874), which encompassed exons 41 to 44 of the DMD gene. The same deletion was not detected in the mother. DHPLC analysis confirmed the presence of both deletions.@*CONCLUSION@#Two fetuses harboring DMD gene deletions but without a family history were discovered. CMA can improve the efficiency for detecting single gene diseases caused by deletions.

Analysis of NRXN1 gene deletion in an autistic patient / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a patient with autism.@*METHODS@#High-throughput sequencing was carried out to detect copy number variations in the patient.@*RESULTS@#DNA sequencing found that the patient has carried a 0.11 Mb deletion in distal 2p16.3 spanning from genomic position 50 820 001 to 50 922 000, which resulted removal of exon 6 and part of intron 7 of the NRXN1 gene. The same deletion was not found his parents and brother.@*CONCLUSION@#Partial deletion of the NRXN1 gene may underlie the disease in this patient.

Germinal mosaicism for partial deletion of the Dystrophin gene in a family affected with Duchenne muscular dystrophy / 中华医学遗传学杂志

OBJECTIVE@#To carry out genetic testing and prenatal diagnosis for a family affected with Duchenne muscular dystrophy (DMD).@*METHODS@#Multiplex ligation dependent probe amplification (MLPA) was used to detect potential deletion and duplication of the Dystrophin gene. Haplotype analysis was performed using five short tandem repeat polymorphism loci (3'-STR, 5'-STR, 45-STR, 49-STR, 50-STR of the DMD gene.@*RESULTS@#A same deletional mutation (exons 51-55) of the DMD gene was detected in two brothers but not in their mother. The patients and fetus have inherited different haplotypes of the Dystrophin gene from their mother, suggesting that the fetus was unaffected.@*CONCLUSION@#The mother was very likely to harbor germline mosaicism for the Dystrophin gene variant. Genetic testing of peripheral blood samples cannot rule out germline mosaicism in the mother. Prenatal diagnosis should be provided for subsequent pregnancies in this family.