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Familial Nephropathy Cocker Spaniel Type (FN)
| Acronym: | FN, ARHN |
| Gene: | COL4A4 |
| Mutation: | c.115A>T |
| Inheritance: | Autosomal recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Familial nephropathy or hereditary nephropathy is a group of genetic disorders of basement membrane (type IV) collagen that cause progressive glomerular disease. Familial Nephropathy (FN) has been referred to in several ways: kidney failure, fatal renal disease, juvenile nephropathy, renal cortical hypoplasia, hereditary nephritis (HN), Autosomal Hereditary Recessive Nephropathy (AHRN) in canines and Alport’s Syndrome in humans.
Affected dogs have proteinuria and juvenile-onset chronic renal failure. Familial nephropathy leads to progressive and irreversible renal failure between 6 months to 2 years. The first clinical signs are excessive water consumption, excessive urine volume, a slowdown in growth, weight loss, reduced appetite, vomiting, and diarrhea. Kidney dysfunction moves inexorably towards the premature death of the animal. Glomerular basement membrane (GBM) thickening and multilamellation is typical for familial nephropathy, and the severity of GBM ultrastructural abnormalities varies with the clinical stage of the disease. The expression of α3(IV) and α4(IV) chains is totally absent in the kidney of affected dogs. Features of obligate carriers are similar to those of unaffected dogs. Around 11% of English Cocker Spaniels are carriers of the genetic mutation responsible for the disease.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Lees, G.E., Helman, R.G., Kashtan, C.E., Michael, A.F., Homco, L.D., Millichamp, N.J., Ninomiya, Y., Sado, Y., Naito, I., and Kim, Y. (1998). A model of autosomal recessive Alport syndrome in English cocker spaniel dogs. Kidney Int 54, 706–719.