A 2-bp deletion mutation in gene leading to lysosomal acid sphingomyelinase deficiency in a Chinese consanguineous pedigree.

Objectives: Niemann-Pick disease type A (NPDA, MIM: 257200) is an autosomal recessive sphingolipidosis caused by lysosomal acid sphingomyelinase (ASM) deficiency. A cluster of genes located at chromosome 11p15 have been reported to be imprinted genes, such as TSSC5, TSSC3, and ZNF215 that flanking SMPD1 gene. It was reported by a few recent studies that SMPD1 gene was paternally imprinted and maternally preferentially expressed.

Analysis of complex chromosomal rearrangements using a combination of current molecular cytogenetic techniques.

Background: Using combined fluorescence in situ hybridization (FISH) and high-throughput whole-genome sequencing (WGS) molecular cytogenetic technology, we aim to analyze the junction breakpoints of complex chromosome rearrangements (CCR) that were difficult to identify by conventional karyotyping analysis and further characterize the genetic causes of recurrent spontaneous abortion.

Results: By leveraging a combination of current molecular techniques, including chromosome karyotype analysis, FISH, and WGS, we comprehensively characterized the extremely complex chromosomal abnormalities in this patient with recurrent spontaneous abortions. Here, we demonstrated that combining these current established molecular techniques is an effective and efficient workflow to identify the structural abnormalities of complex chromosomes and locate the rearrangement of DNA fragments.

Mutation spectrum of six genes in Chinese phenylketonuria patients obtained through next-generation sequencing.

Background: The identification of gene variants plays an important role in the diagnosis of genetic diseases.

Methodology/principal Findings: To develop a rapid method for the diagnosis of phenylketonuria (PKU) and tetrahydrobiopterin (BH4) deficiency, we designed a multiplex, PCR-based primer panel to amplify all the exons and flanking regions (50 bp average) of six PKU-associated genes (PAH, PTS, GCH1, QDPR, PCBD1 and GFRP). The Ion Torrent Personal Genome Machine (PGM) System was used to detect mutations in all the exons of these six genes.

Genome-wide oligonucleotide array comparative genomic hybridization for etiological diagnosis of mental retardation: a multicenter experience of 1499 clinical cases.

To assess the clinical utility of genome-wide oligonucleotide arrays in diagnosis of mental retardation and to address issues relating to interpretation of copy number changes (CNCs), we collected results on a total of 1499 proband patients from five academic diagnostic laboratories where the same 44K array platform has been used. Three of the five laboratories achieved a diagnostic yield of 14% and the other two had a yield of 11 and 7%, respectively. Approximately 80% of the abnormal cases had a single segment deletion or duplication, whereas the remaining 20% had a compound genomic imbalance involving two or more DNA segments.

Clinical and genomic characterization of distal duplications and deletions of chromosome 4q: study of two cases and review of the literature.

Variable clinical presentations of patients with chromosomally detected deletions in the distal long arm (q) of chromosome 4 have been reported. The lack of molecular characterization of the deletion sizes and deleted genes hinders further genotype-phenotype correlation. Using a validated oligonucleotide array comparative genomic hybridization (oaCGH) analysis, we examined two patients with apparent chromosomal deletions in the distal 4q region.

Very low density lipoprotein receptor, a negative regulator of the wnt signaling pathway and choroidal neovascularization.

Choroidal neovascularization (CNV) in age-related macular degeneration is a leading cause of blindness. Very low density lipoprotein receptor gene knock-out (Vldlr(-/-)) mice have been shown to develop subretinal neovascularization (NV) with an unknown mechanism. The present study showed that in Vldlr(-/-) mice, NV initiated in the choroid and progressed to penetrate the retinal pigment epithelium layer, proliferating in the subretinal space.

Rat strain-dependent susceptibility to ischemia-induced retinopathy associated with retinal vascular endothelial growth factor regulation.

Vascular endothelial growth factor (VEGF) is a potent inflammation, vascular permeability, and angiogenic factor. Variations of the VEGF gene are implicated in the pathogenesis of diabetic retinopathy. Previous studies have shown that Brown Norway (BN) rats have higher retinal VEGF levels and more severe retinal vascular leakage than Sprague-Dawley (SD) rats in response to ischemia and diabetes.

Therapeutic potential of angiostatin in diabetic nephropathy.

Angiostatin is a proteolytic fragment of plasminogen and a potent angiogenic inhibitor. Previous studies have shown that angiostatin inhibits retinal neovascularization and reduces retinal vascular permeability in diabetic retinopathy. Here, it is reported for the first time that angiostatin is also implicated in diabetic nephropathy (DN).

Effects of oxidized and glycated LDL on gene expression in human retinal capillary pericytes.

Purpose: Modified (oxidized and/or glycated) low-density lipoproteins (LDLs) have been implicated in retinal pericyte loss, one of the major pathologic features of early-stage diabetic retinopathy. To delineate underlying molecular mechanisms, the present study was designed to explore the global effects of modified LDL on pericyte gene expression.

Methods: Quiescent human retinal pericytes were exposed to native LDL (N-LDL), glycated LDL (G-LDL), and heavily oxidized-glycated LDL (HOG-LDL) for 24 hours, and gene expression was evaluated by DNA microarray analysis.

Effects of modified low-density lipoproteins on human retinal pericyte survival.

According to a current paradigm cardiovascular diseases can be initiated by exposure of vascular cells to qualitatively modified low-density lipoproteins (LDL). Capillary leakage, an early feature of diabetic retinopathy, results in the exposure of retinal pericytes to modified LDL, including glycated (G-LDL) and heavily oxidized glycated LDL (HOG-LDL). We demonstrate here that modified LDL inhibits the proliferation and survival of cultured human retinal pericytes.

Downregulation of cone-specific gene expression and degeneration of cone photoreceptors in the Rpe65-/- mouse at early ages.

Purpose: RPE65 is essential for the generation of 11-cis retinal. Rod photoreceptors in the RPE65-knockout (Rpe65(-/-)) mouse are known to degenerate slowly with age. This study was designed to examine cone photoreceptors and the expression of cone-specific genes in the Rpe65(-/-) mouse.

Decreased expression of pigment epithelium-derived factor is involved in the pathogenesis of diabetic nephropathy.

Pigment epithelium-derived factor (PEDF) is a potent angiogenic inhibitor. Previous studies have shown that decreased ocular levels of PEDF are associated with diabetic retinopathy. However, the implication of PEDF expression in diabetic nephropathy has not been revealed.

A mouse model of sitosterolemia: absence of Abcg8/sterolin-2 results in failure to secrete biliary cholesterol.

Background: Mutations in either of two genes comprising the STSL locus, ATP-binding cassette (ABC)-transporters ABCG5 (encoding sterolin-1) and ABCG8 (encoding sterolin-2), result in sitosterolemia, a rare autosomal recessive disorder of sterol trafficking characterized by increased plasma plant sterol levels. Based upon the genetics of sitosterolemia, ABCG5/sterolin-1 and ABCG8/sterolin-2 are hypothesized to function as obligate heterodimers. No phenotypic difference has yet been described in humans with complete defects in either ABCG5 or ABCG8.

The rat STSL locus: characterization, chromosomal assignment, and genetic variations in sitosterolemic hypertensive rats.

Background: Elevated plant sterol accumulation has been reported in the spontaneously hypertensive rat (SHR), the stroke-prone spontaneously hypertensive rat (SHRSP) and the Wistar-Kyoto (WKY) rat. Additionally, a blood pressure quantitative trait locus (QTL) has been mapped to rat chromosome 6 in a New Zealand genetically hypertensive rat strain (GH rat). ABCG5 and ABCG8 (encoding sterolin-1 and sterolin-2 respectively) have been shown to be responsible for causing sitosterolemia in humans.

Molecular cloning, genomic organization, genetic variations, and characterization of murine sterolin genes Abcg5 and Abcg8.

Mammalian physiological processes can distinguish between dietary cholesterol and non-cholesterol, retaining very little of the non-cholesterol in their bodies. We have recently identified two genes, ABCG5 and ABCG8, encoding sterolin-1 and -2 respectively, mutations of which cause the human disease sitosterolemia. We report here the mouse cDNAs and genomic organization of Abcg5 and Abcg8.