Alternative titles; symbols
ORPHA: 656; DO: 0111129;
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
Gene/Locus |
Gene/Locus MIM number |
|---|---|---|---|---|---|---|
| 11q22.1 | Glomerulosclerosis, focal segmental, 2 | 603965 | Autosomal dominant | 3 | TRPC6 | 603652 |
A number sign (#) is used with this entry because of evidence that this form of hereditary renal disease, termed focal segmental glomerulosclerosis-2 (FSGS2), is caused by heterozygous mutation in the TRPC6 gene (603652) on chromosome 11q22.
Focal segmental glomerulosclerosis (FSGS) is a pathologic entity associated clinically with proteinuria, the nephrotic syndrome (NPHS), and progressive loss of renal function. It is a common cause of end-stage renal disease (ESRD) (review by Meyrier, 2005).
For a general phenotypic description and a discussion of genetic heterogeneity of focal segmental glomerulosclerosis and nephrotic syndrome (NPHS), see FSGS1 (603278).
Winn et al. (1999, 1999) reported a 399-member Caucasian kindred of British heritage dating back 7 generations from the south of New Zealand in which 14 deceased individuals had had ESRD, 14 living family members were on dialysis or had undergone renal transplantation, and 3 individuals were found to have proteinuria greater than 3+ by qualitative urinalysis.
In a 399-member Caucasian kindred of British heritage with hereditary renal disease, Winn et al. (1999, 1999) found linkage to chromosome 11q21-q22, with a maximum lod score of 9.89.
Genetic Heterogeneity
In a 5-generation, 65-member Caucasian kindred from rural eastern North Carolina, Winn et al. (1999) excluded linkage to chromosome 11 and to the previously described locus on 19q13 (FSGS1). There were no shared haplotypes among affected individuals in 3 smaller families. The findings demonstrated genetic heterogeneity in FSGS, with at least 3 genes causing this phenotype.
The transmission pattern of FSGS in the family reported by Winn et al. (2005) and the families reported by Reiser et al. (2005) was consistent with autosomal dominant inheritance.
In affected members of the British family segregating FSGS linked to chromosome 11q21-q22 identified by Winn et al. (1999), Winn et al. (2005) identified a mutation in exon 2 of the TRPC6 gene that caused a missense change in the first ankyrin repeat of the protein (P112Q; 603652.0001).
Reiser et al. (2005) identified 5 families with autosomal dominant focal segmental glomerulosclerosis in which the disease segregated with heterozygous mutations in the TRPC6 gene (603652.0002-603652.0006). Two of the TRPC6 mutants had increased current amplitudes. The authors demonstrated that TRPC6 is expressed in podocytes and is a component of the glomerular slit diaphragm. These data showed that TRPC6 channel activity at the slit diaphragm is essential for proper regulation of podocyte structure and function.
In the literature, the clinical term 'nephrotic syndrome' (NPHS) and the pathologic term 'focal segmental glomerulosclerosis' (FSGS) have often been used to refer to the same disease entity. In OMIM, these disorders are classified as NPHS or FSGS according to how they were first designated in the literature.
Meyrier, A. Mechanisms of disease: focal segmental glomerulosclerosis. Nature Clin. Pract. Nephrol. 1: 44-54, 2005. [PubMed: 16932363] [Full Text: https://doi.org/10.1038/ncpneph0025]
Reiser, J., Polu, K. R., Moller, C. C., Kenlan, P., Altintas, M. M., Wei, C., Faul, C., Herbert, S., Villegas, I., Avila-Casado, C., McGee, M., Sugimoto, H., Brown, D., Kalluri, R., Mundel, P., Smith, P. L., Clapham, D. E., Pollak, M. R. TRPC6 is a glomerular slit diaphragm-associated channel required for normal renal function. Nature Genet. 37: 739-744, 2005. [PubMed: 15924139] [Full Text: https://doi.org/10.1038/ng1592]
Winn, M. P., Conlon, P. J., Lynn, K. L., Farrington, M. K., Creazzo, T., Hawkins, A. F., Daskalakis, N., Kwan, S. Y., Ebersviller, S., Burchette, J. L., Pericak-Vance, M. A., Howell, D. N., Vance, J. M., Rosenberg, P. B. A mutation in the TRPC6 cation channel causes familial focal segmental glomerulosclerosis. Science 308: 1801-1804, 2005. [PubMed: 15879175] [Full Text: https://doi.org/10.1126/science.1106215]
Winn, M. P., Conlon, P. J., Lynn, K. L., Howell, D. N., Gross, D. A., Rogala, A. R., Smith, A. H., Graham, F. L., Bembe, M., Quarles, L. D., Pericak-Vance, M. A., Vance, J. M. Clinical and genetic heterogeneity in familial focal segmental glomerulosclerosis. Kidney Int. 55: 1241-1246, 1999. [PubMed: 10200986] [Full Text: https://doi.org/10.1046/j.1523-1755.1999.00384.x]
Winn, M. P., Conlon, P. J., Lynn, K. L., Howell, D. N., Slotterbeck, B. D., Smith, A. H., Graham, F. L., Bembe, M., Quarles, L. D., Pericak-Vance, M. A., Vance, J. M. Linkage of a gene causing familial focal segmental glomerulosclerosis to chromosome 11 and further evidence of genetic heterogeneity. Genomics 58: 113-120, 1999. [PubMed: 10368108] [Full Text: https://doi.org/10.1006/geno.1999.5828]