Muscular dystrophy‐dystroglycanopathy (limb‐girdle), type C, 9 (MDDGC9) is the rarest type of autosomal recessive muscular dystrophies. MDDGC9 is manifested with an early onset in childhood. Patients with MDDGC9 usually identified with defective glycosylation of DAG1, hence it is known as “dystroglycanopathies”. Here, we report a Chinese pedigree presented with mild MDDGC9. The proband is a 64 years old Chinese man. In this family, both the proband and proband's younger brother have been suffering from mild and late onset MDDGC9. Muscle biopsy showed that the left deltoid muscle with an advanced stage of dystrophic change. Immunohistochemistry staining of dystrophin, α‐sarcoglycan, β‐sarcoglycan and dysferlin are normal. Molecular genetic analysis of the proband has been done with whole exome sequencing. A homozygous novel missense mutation (c.2326C>T; p.R776C) in the exon 3 of the DAG1 gene has been identified in the proband. Sanger sequencing revealed that this missense mutation is co‐segregated well among the affected and unaffected (carrier) family members. This mutation is not detected in 200 normal healthy control individuals. This novel homozygous missense mutation (c.2326C>T) causes substitution of arginine by cystine at the position of 776 (p.R776C) which is evolutionarily highly conserved. Immunoblotting studies revealed that a significant reduction of α‐dystroglycan expression in the muscle tissue. The novelty of our study is that it is a first report of DAG1 associated muscular dystrophy‐dystroglycanopathy (limb‐girdle), type C, 9 (MDDGC9) with mild and late age of onset. In Chinese population this is the first report of DAG1 associated MDDGC9.

Acute intermittent porphyria (AIP) is a rare hereditary metabolic disease with an autosomal dominant mode of inheritance. Germline mutations of HMBS gene causes AIP. Mutation of HMBS gene results into the partial deficiency of the heme biosynthetic enzyme hydroxymethylbilane synthase. AIP is clinically manifested with abdominal pain, vomiting, and neurological complaints. Additionally, an extreme phenotypic heterogeneity has been reported in AIP patients with mutations in HMBS gene. Here, we investigated a Chinese patient with AIP. The proband is a 28-year-old Chinese male manifested with severe stomach ache, constipation, nausea and depression. Proband’s father and mother is normal. Proband’s blood sample was collected and genomic DNA was extracted. Whole exome sequencing and Sanger sequencing identified a heterozygous novel single nucleotide deletion (c.809delC) in exon 12 of HMBS gene in the proband. This mutation leads to frameshift followed by formation of a truncated (p.Ala270Valfs∗2) HMBS protein with 272 amino acids comparing with the wild type HMBS protein of 361 amino acids. This mutation has not been found in proband’s unaffected parents as well as in 100 healthy normal control. According to the variant interpretation guidelines of American College of Medical Genetics and Genomics (ACMG), this variant is classified as “likely pathogenic” variant. Our findings expand the mutational spectra of HMBS gene related AIP which are significant for screening and genetic diagnosis for AIP.

As the most common inherited retinal degenerations, retinitis pigmentosa (RP) is clinically and genetically heterogeneous. Some of the RP genes are also associated with other retinal diseases, such as LCA (Leber's congenital amaurosis) and CORD (cone-rod dystrophy). Here, in our molecular diagnosis of 99 Chinese RP patients using targeted gene capture sequencing, three probands were found to carry mutations of RPGRIP1, which was known to be associated with pathogenesis of LCA and CORD. By further clinical analysis, two probands were confirmed to be RP patients and one was confirmed to be LCA patient. These novel mutations were co-segregated with the disease phenotype in their families. Our result not only expands the mutational spectrum of the RPGRIP1 gene but also gives supports to clinical diagnosis and molecular treatment of RP patients.

Autosomal dominant adult-onset demyelinating leukodystrophy (ADLD) is a very rare neurological disorder featured with late onset, slowly progressive central nervous system demyelination. Duplication or over expression of the lamin B1 (LMNB1) gene causes ADLD. In this study, we undertook a comprehensive clinical evaluation and genetic detection for a Chinese family with ADLD. The proband is a 52-year old man manifested with autonomic abnormalities, pyramidal tract dysfunction. MRI brain scan identified bilateral symmetric white matter (WM) hyper-intensities in periventricular and semi-oval WM, cerebral peduncles and middle cerebellar peduncles. The proband has a positive autosomal dominant family history with similar clinical manifestations with a trend of genetic anticipation. In order to understand the genetic cause of the disease in this family, target exome capture based next generation sequencing has been done, but no causative variants or possibly pathogenic variants has been identified. However, Multiplex ligand-dependent probe amplification (MLPA) showed whole duplication of LMNB1 gene which is co-segregated with the disease phenotype in this family. This is the first genetically confirmed LMNB1 associated ADLD pedigree from China.

BackgroundRecent studies indicated that a synthetic oligonucleotide containing un-methylated CpG oligodeoxynucleotides (CpG-ODN) has a potential function for cancer therapy. In this study, we evaluated the chemosensitizing effects of CpG-ODN in 5-fluorouracil (5-FU)-treated HepG2 human hepatoma cells.MethodsCell viability assay were utilized to evaluate the direct cytotoxicity of CpG-ODN in the presence or absence of 5-FU in HepG2 cells, and apoptosis as well as cell-cycle was examined by flow cytometry analysis. The mRNA expression of Bcl-2, Livin and Survivin within HepG2 cells treated with CpG-ODN and/or 5-FU were analyzed by Real Time PCR assay in vitro.ResultsCpG-ODN in combination with 5-FU could decrease cell viability, increase apoptosis and further induce HepG2 cells cycle arrest at S phase when compared with CpG-ODN or 5-FU. CpG-ODN or 5-FU could down-regulate the mRNA expression of Bcl-2 within HepG2 cells. The mRNA expression of Livin and Survivin decreased in cells treated with CpG-ODN alone but increased in cells treated with 5-FU alone. However, CpG-ODN in combination with 5-FU could down-regulate the mRNA expression of Livin and Survivin within HepG2 cells.ConclusionsOur finding demonstrated that CpG-ODN enhanced the chemosentivity of 5-FU in HepG2 human hepatoma cells at least in part by down-regulating the expression of Livin and Survivin, leading to apoptosis and further inducing cell cycle arrest at S phase. Therefore, CpG-ODN may be a potential candidate as chemosensitizer for human hepatocellular carcinoma.

ABSTRACT

Germline mutations of the APC gene are associated with an autosomal dominant precancerous condition, termed familial adenomatous polyposis (FAP). FAP is clinically manifested by the presence of multiple colorectal adenomas or polyps. Gradually, these colorectal adenomas or polyps inevitably result in colorectal cancer by the third-to fourth decade of life. Surgical interventions or total proctocolectomy is the best possible treatment for FAP. Here, we present a clinical molecular study of a five generation Chinese family with FAP. Diagnosis of FAP was made on the basis of clinical manifestations, family history and medical (colonoscopy and histopathology) records. Blood samples were collected and genomic DNA was extracted. Genetic screening of the APC gene was performed by targeted next-generation sequencing and quantitative real-time PCR. Targeted next generation sequencing identified a novel heterozygous large deletion [exon5-exon16; c.423_8532del] of APC gene, which segregated with the FAP phenotypes in the proband and in all the affected family members. Unaffected family members and normal controls did not carry this deletion. In the Chinese population, most of the previously reported APC gene mutations are missense mutations. This is the first report describing the largest deletion of the APC gene in the Chinese population associated with FAP.

Neurofibromatosis type 1 (NF1) is an autosomal dominant, multi-system, neurocutaneous disorder, manifested with neurofibromas and Cafe´-au-lait spots. Germline mutations in NF1 gene are associated with Neurofibromatosis type 1. NF1 gene encodes neurofibromin, a RAS-specific GTPase activating protein. In our study, we present a clinical molecular study of four Chinese probands with NF1 from four unrelated families, showing extreme phenotypic variation with rare phenotype. In family 1, the proband is a 16 months old girl with multiple café-au-lait spots throughout her whole body. In family 2, the proband is a 6 months old girl with several café-au-lait spots mostly in her trunk and in lower limbs. In family 3, the proband is a 4 months old boy with several café-au-lait spots, tibial pseudarthrosis, and chronic iron deficiency anemia. In family 4, the proband is a 14 years old boy with multiple café-au-lait spots of variable sizes. Targeted exome capture based next generation sequencing and Sanger sequencing identified a novel mutation and three previously reported mutations in these four probands. These four mutations in NF1 gene were causing disease phenotypes in these four probands and was absent in unaffected family members and in healthy controls. According to the variant interpretation guideline of American College of Medical Genetics and Genomics (ACMG), these four mutations, are classified as “likely pathogenic”. Our result expands the mutational spectrum of the NF1 gene associated with neurofibromatosis type1.