Project description:Homozygosity mapping using genome-wide SNP arrys is a useful tool to map causative genes of mendelian disorders in consanguineous patients To search for LOH (loss of heterozygosity) regions we hybridized genomic DNA from a OI patient and a normal sibling against Human610quad beadarrays from Illumina (www.illumina.com). Genotyping data was analyzed with BeadStudio software (www.illumina.com)
Project description:homozygosity mapping in a family with ovarian failure Two affected and four unafected siblings from consanguineous family were studied to identify shared regions of homozygosity in affected females with gonadal dysgenesis
Project description:Homozygosity mapping using genome-wide SNP arrys is a useful tool to map causative genes of mendelian disorders in consanguineous patients To search for LOH (loss of heterozygosity) regions we hybridized genomic DNA from a OI patient and a normal sibling against Human610quad beadarrays from Illumina (www.illumina.com). Genotyping data was analyzed with BeadStudio software (www.illumina.com) Genomic DNAs from OI affected individual and non-affected sibling were hybridized each on an Illumina Human610Quad Genotyping BeadChip. Image data was analyzed using Beadstudio 3.1.3 software. CNV and LOH (larger than 1 Mb) analysis was performed using the cnvPartition 2.3.4. It was considered as a region of interest those showing LOH in the affected individual but not in the non-affected sibling.
Project description:In this study, we use transcriptomic approaches, to delineate a non-coding TAPT1 mutation (c.1237-52G>A) resulting in a protein-null allele, that segregated with a congenital recessive disease recessive consisting of Osteogenesis Imperfecta (OI) and neonatal progeria.
Project description:In this study, we use transcriptomic approaches, to delineate a non-coding TAPT1 mutation (c.1237-52G>A) resulting in a protein-null allele, that segregated with a congenital recessive disease recessive consisting of Osteogenesis Imperfecta (OI) and neonatal progeria.
Project description:Osteogenesis Imperfecta is characterized by short stature however the cellular mechanisms behind this phenotype are unclear. We isolated tibial and femoral cartilage growth plate chondrocytes from postnatal day 5 wild type and Aga2 (a model of OI) mice and analyzed differential expression patterns using single cell RNA-seq
Project description:Osteogenesis imperfecta (OI) is most commonly caused by autosomal dominant mutations in genes encoding collagen type-I. Here, we test the hypothesis that modulation of the endoplasmic reticulum (ER) proteostasis network via the unfolded protein response (UPR) can improve the folding and secretion of the lethal osteogenesis imperfecta (OI)-causing G425S a1(I) variant. We show that specific induction of the UPR’s XBP1s transcriptional response enhances G425S a1(I) secretion up to ~300% of basal levels. Notably, the effect is selective – WT a1(I) secretion is unaltered by XBP1s. XBP1s pathway activation appears to post-translationally enhance the folding/assembly and secretion of G425S a1(I). Consistent with this notion, we find that the stable, triple-helical collagen-I secreted by XBP1s-activated G425S a1(I) patient fibroblasts includes a higher proportion of the mutant a1(I) polypeptide than the collagen-I secreted under basal ER proteostasis conditions.
Project description:Osteogenesis imperfecta (OI) is a serious genetic bone disorder characterized by congenital low bone mass, deformity and frequent fractures. Type XV OI is a moderate to severe form of skeletal dysplasia caused by WNT1 mutations. In this cohort study from southern China, we summarized the clinical phenotypes of patients with WNT1 mutations and found the proportion of type XV patients was around 10.3% (25 out of 243) with diverse phenotypic spectrums. Functional assays indicated that mutations of WNT1 significantly impaired its secretion and effective activity, leading to moderate to severe clinical manifestations, porous bone structure and enhanced osteoclastic activities. Analysis of proteomic data from human skeleton indicated that the expression of SOST was dramatically reduced in type XV patients. Single-cell transcriptome data generated from human tibia samples revealed aberrant differentiation trajectory of skeletal progenitors and impaired maturation of osteocytes, resulting in excessive CXCL12+ progenitors and abnormal cell populations with adipogenic characteristics. The integration of multi-omics data from human skeleton delineates how WNT1 regulates the differentiation and maturation of skeletal progenitors, which will provide a new direction for the treatment strategy of type XV osteogenesis imperfecta and relative low bone mass diseases such as early onset osteoporosis.
Project description:Osteogenesis imperfecta (OI) is a group of diseases caused by defects in type I collagen processing which result in skeletal fragility. While these disorders have traditionally been regarded as defects in osteoblast function, the role of matrix-embedded osteocytes, descendants of osteoblasts, in OI pathogenesis remains unknown. The homozygous human SP7 (c.946C > T, R316C) mutation results in a recessive form of osteogenesis imperfecta characterized by short stature, fragility fractures, low bone mineral density, and osteocyte dendrite defects. To better understand how the osteogenesis imperfecta-causingSP7 R316Cmutation affects the function of this transcription factor in different osteoblast lineage cells in bone, we generatedSp7 R342Cknock-in mice. Homozygous mutantSp7 R342C/R342Cmice demonstrate increased cortical porosity and reduced cortical bone mineral density, findings consistent with phenotypes observed in patients with this mutation. Sp7 R342Cmice show osteocyte dendrite defects, increased osteocyte apoptosis, and intracortical bone remodeling characterized by ectopic intracortical osteoclasts and elevated Tnfsf11 expression by osteocytes. Remarkably, these overt defects in osteocyte function contrast to preserved osteoblast function, suggesting that this Sp7 point mutation selectively interferes with the function of this transcription factor in osteocytes but not osteoblasts. Osteocyte morphology changes in Sp7 R342C/R342Cmice were not restored by inhibiting osteoclast formation, indicating that dendrite defects lie upstream of high intra-cortical osteoclast activity in this model. Moreover, transcriptomic profiling reveals that the expression of a core set osteocyte-enriched genes is highly dysregulated by the R342C mutation. Thus, this model supports a model in which osteocyte dysfunction can drive osteogenesis imperfecta pathogenesis, and provides a valuable resource to test novel therapeutic approaches and to understand the osteocyte-specific role of SP7 in bone homeostasis and remodeling.
