Anti-COL4A3 (native) polyclonal antibody

Focal segmental glomerulosclerosis (FSGS) is a histologically identifiable glomerular injury often leading to proteinuria and renal failure. To identify its causal genes, whole-exome sequencing and Sanger sequencing were performed on a large Chinese cohort that comprised 40 FSGS families, 50 sporadic FSGS patients, 9 independent autosomal recessive Alport's syndrome (ARAS) patients, and 190 ethnically matched healthy controls. Patients with extrarenal manifestations, indicating systemic diseases or other known hereditary renal diseases, were excluded. Heterozygous COL4A3 mutations were identified in five (12.5%) FSGS families and one (2%) sporadic FSGS patient. All identified mutations disrupted highly conserved protein sequences and none of them was found in either public databases or the 190 healthy controls. Of the FSGS patients with heterozygous COL4A3 mutations, segmental thinning of the glomerular base membrane (GBM) was only detected in the patient with electronic microscopy examination results available. Five ARAS patients (55.6%) had homozygous or compound-heterozygous mutations in COL4A3 or COL4A4. Serious changes in the GBM, hearing loss, and ocular abnormalities were found in 100%, 80%, and 40% of the ARAS patients, respectively. Overall, a new sub-group of FSGS patients resulting from heterozygous COL4A3 mutations was identified. The mutations are relatively frequent in families diagnosed with inherited forms of FSGS. Thus, we suggest screening for COL4A3 mutations in familial FSGS patients.

Alport syndrome (ATS) is a hereditary nephropathy often associated with sensorineural hypoacusis and ocular abnormalities. Mutations in the COL4A5 gene cause X-linked ATS. Mutations in COL4A4 and COL4A3 genes have been reported in both autosomal recessive and autosomal dominant ATS. The conventional mutation screening, performed by DHPLC and/or Sanger sequencing, is time-consuming and has relatively high costs because of the absence of hot spots and to the high number of exons per gene: 51 (COL4A5), 48 (COL4A4) and 52 (COL4A3). Several months are usually necessary to complete the diagnosis, especially in cases with less informative pedigrees. To overcome these limitations, we designed a next-generation sequencing (NGS) protocol enabling simultaneous detection of all possible variants in the three genes. We used a method coupling selective amplification to the 454 Roche DNA sequencing platform (Genome Sequencer junior). The application of this technology allowed us to identify the second mutation in two ATS patients (p.Ser1147Phe in COL4A3 and p.Arg1682Trp in COL4A4) and to reconsider the diagnosis of ATS in a third patient. This study, therefore, illustrates the successful application of NGS to mutation screening of Mendelian disorders with locus heterogeneity. European Journal of Human Genetics (2012) 20, 50-57; doi:10.1038/ejhg.2011.164; published online 7 September 2011