A novel splice site mutation in OTC gene of a female with ornithine transcarbamylase deficiency and her asymptomatic mosaic father

Ornithine transcarbamylase deficiency is an X-linked disease with a wide range of clinical severity and manifestation age both in males and females. Here, we describe a case which is caused by a novel c.78-1G[A splice site mutation, which on mRNA level leads to a 1-bp deletion and a frameshift (c.78delG (p.C27Vfs*11)) in OTC exon 2 in a young girl. The same mutation has been detected in a mosaic state in her asymptomatic father.

Hereditary spherocytosis due to a novel c. 5798+ 1G>A variant of the SPTB gene / 中华医学遗传学杂志

Objective@#To explore the genetic basis of a pedigree affected with hereditary spherocytosis.@*Methods@#Peripheral blood samples were collected from 17 members of the pedigree. Genomic DNA of the proband was subjected to next generation sequencing. Candidate variant was validated by co-segregation analysis. pCAS2c.5798+ 1G and pCAS2c.5798+ 1A plasmids were constructed by homologous recombination and transfected into 293T cells. Reverse transcription PCR, TA cloning and Sanger sequencing were used to analyze the effect of candidate variant on splicing. Meanwhile, peripheral blood RNAs were extracted to analyze the effect of candidate variant on splicing in vivo.@*Results@#The proband was found to carry a c. 5798+ 1G>A variant of the SPTB gene. The variant has co-segregated with the phenotype in the pedigree. In vitro and in vivo splicing experiments confirmed that the mutation has significantly affected the splicing, resulting in shift of reading frame and produced a premature termination codon.@*Conclusion@#The novel c. 5798+ 1G>A variant of the SPTB gene probably underlies the pathogenesis of hereditary spherocytosis in this pedigree.

Comprehensive genetic diagnosis of patients with Duchenne/Becker muscular dystrophy (DMD/BMD) and pathogenicity analysis of splice site variants in the DMD gene / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are caused by mutations in the DMD gene. The aim of this study is to identify pathogenic DMD variants in probands and reduce the risk of recurrence of the disease in affected families. Variations in 100 unrelated DMD/BMD patients were detected by multiplex ligation-dependent probe amplification (MLPA) and next-generation sequencing (NGS). Pathogenic variants in DMD were successfully identified in all cases, and 11 of them were novel. The most common mutations were intragenic deletions (69%), with two hotspots located in the 5′ end (exons 2–19) and the central of the DMD gene (exons 45–55), while point mutations were observed in 22% patients. Further, c.1149+1G>A and c.1150-2A>G were confirmed by hybrid minigene splicing assay (HMSA). This two splice site mutations would lead to two aberrant DMD isoforms which give rise to severely truncated protein. Therefore, the clinical use of MLPA, NGS, and HMSA is an effective strategy to identify variants. Importantly, eight embryos were terminated pregnancies according to prenatal diagnosis and a healthy boy was successfully delivered by preimplantation genetic diagnosis (PGD). Early and accurate genetic diagnosis is essential for prenatal diagnosis/PGD to reduce the risk of recurrence of DMD in affected families.

Comprehensive genetic diagnosis of patients with Duchenne/Becker muscular dystrophy (DMD/BMD) and pathogenicity analysis of splice site variants in the DMD gene / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are caused by mutations in the DMD gene. The aim of this study is to identify pathogenic DMD variants in probands and reduce the risk of recurrence of the disease in affected families. Variations in 100 unrelated DMD/BMD patients were detected by multiplex ligation-dependent probe amplification (MLPA) and next-generation sequencing (NGS). Pathogenic variants in DMD were successfully identified in all cases, and 11 of them were novel. The most common mutations were intragenic deletions (69%), with two hotspots located in the 5' end (exons 2-19) and the central of the DMD gene (exons 45-55), while point mutations were observed in 22% patients. Further, c.1149+1G>A and c.1150-2A>G were confirmed by hybrid minigene splicing assay (HMSA). This two splice site mutations would lead to two aberrant DMD isoforms which give rise to severely truncated protein. Therefore, the clinical use of MLPA, NGS, and HMSA is an effective strategy to identify variants. Importantly, eight embryos were terminated pregnancies according to prenatal diagnosis and a healthy boy was successfully delivered by preimplantation genetic diagnosis (PGD). Early and accurate genetic diagnosis is essential for prenatal diagnosis/PGD to reduce the risk of recurrence of DMD in affected families.

Clinical profile in arrhythmogenic cardiomyopathy and a recessive plakophilin-2 gene mutation

Objective Arrhythmogenic cardiomyopathy (ACM) is not an uncommon cause of cardiac morbidity in Kashmir valley. This study was designed to document various clinical features and to sequence exons 11 and 12 of plakophilin 2 (PKP2) gene in these patients. Methods ACM patients who attended cardiology outpatient department of our institute from January 2014 to April 2015 were included in the study. Their records were reviewed. Controls were randomly selected, who had no history or family history of cardiac illness and had a normal cardiac examination. A blood sample was also taken from both the groups for sequencing of exon 11 and 12 of PKP2 gene. ACM patients were followed up until July 2016. Results Eleven ACM patients and seven controls were included in the study. Most common mode of presentation was ventricular tachycardia (VT). Two patients had left ventricular (LV) systolic dysfunction. One patient had a splice site mutation in exon 12 of PKP2 gene and one patient died during follow-up. One of the controls had an intronic variation that has no pathogenic significance vis-à-vis ACM. Conclusion Our study describes various clinical parameters in ACM patients and a recessive plakophilin 2 mutation after a limited PKP2 gene sequencing.

Genetic analysis of a family with Usher syndrome / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To analyze the clinical features of a Usher syndrome family and explore the pathogenic gene of the disease. <p>METHODS: A Chinese family with Usher syndrome was involved in our study. After informed consent, careful clinical examinations were taken and 4mL blood were obtained. The whole genome DNA was extracted and target-captured next generation sequencing of the proband was performed to identify suspected mutations. We used Sanger sequencing to verify the detected mutations in all the members of the family, as well as in 100 normal controls. <p>RESULTS: In addition to typical retinitis pigmentosa, the patients suffered from mild to moderate sensorineural deafness. Sequencing results revealed compound heterozygous mutations(c.2310_2311insA and c.8559-2A>G)of <i>USH2A</i> gene in the patients, and either of the mutations was found in normal relatives that had consanguinity with the patients. Both of the mutations were not found in other members of the family and normal individuals. <p>CONCLUSION: <i>USH2A</i> is the pathogenic gene of the disease in this family. The mutation c.8559-2A>G(IVS42)is a previously reported mutation, while the mutation c.2310_2311 insA(p.E771Rfs*8)is a novel mutation. The study has expanded the mutation spectrum of <i>USH2A</i> gene resulting in Usher syndrome.

A Case Report of Glucose Transporter 1 Deficiency Syndrome with a Novel Splice Site Mutation (SLC2A1: c.680-2delA) / 대한소아신경학회지

Glucose transporter type 1 deficiency syndrome (GLUT1-DS) is caused by impaired glucose transport across the blood-brain barrier (BBB) and characterized by infantile seizures, developmental delay, acquired microcephaly, spasticity, ataxia, and a low cerebrospinal glucose concentration (hypoglycorrhachia). A diagnosis of GLUT1-DS is biochemically established in neurologically impaired patients with hypoglycorrhachia in the normoglycemia. GLUT1-DS can be confirmed by mutation analysis of the solute carrier family 2 (facilitated glucose transporter), member 1 (SLC2A1) gene or reduced 3-O-methyl-D-glucose uptake into erythrocytes. The patient was a 12-year-old boy born at term. He had experienced seizures from 4 months of age. Electroencephalography (EEG) did not show epileptiform activity. Brain magnetic resonance imaging (MRI) revealed mild diffuse cortical atrophy and ventricular dilatation. Furthermore, he showed developmental delay, mental retardation, and ataxia, which all became more apparent with age progression. For 7 years, he had experienced paroxysmal episodes of atonic behavioral changes that were aggravated before meals or when he became tired. When he was 12 years old, cerebrospinal fluid (CSF) analysis revealed a low glucose concentration in the normal serum glucose and lactate levels. Under the impression of GLUT1-DS, mutation analysis of the SLC2A1 gene by direct sequencing was performed using white blood cells, and c.680-2delA of intron 5 was found. We describe a GLUT1-DS patient with a typical natural history of GLUT1-DS through a long term follow-up visits, with a novel splice site mutation (SLC2A1: c.6802delA).

Molecular Characterisation Of Mutations In Congenital Adrenal Hyperplasia In Indian Subjects.

Congenital adrenal hyperplasia (CAH) is one of the most common outosomal recessive condition causing ambiguous genitalia in females. Often, it's a life threatening condition occurring with 1 in 5000 to 15000 live births and caused due to mutations in CYP21 gene encoding the enzyme 21-hydroxylase. 25 cases of CAH reporting at All India Institute of Medical Sciences, New Delhi, were analysed for mutations in the gene CYP21 and the results are discussed.