Protein Losing Nephropathy (PLN, 2 variants)

Protein Losing Nephropathy (PLN) is a condition in which the kidneys lose significant amounts of protein, particularly albumin, into the urine. This happens when the kidney’s filtration system (specifically the glomeruli) becomes damaged, allowing proteins that should be retained in the blood to pass into the urine. This leads to muscle wasting, abnormal fluid accumulation in the skin and limbs, and kidney failure.

Dogs carrying one or two copies of the mutations are at risk for developing PLN, with those possessing two copies having a significantly higher likelihood of the disease. However, this mutation is incompletely penetrant, indicating that other genetic and environmental factors also play a role in the disease’s development.

Risk assessment for PLN in the Soft Coated Wheaten Terrier and Airedale Terrier can be done by screening for two different mutations (one on gene KIRREL2 and one on gene NPHS1) that both code for proteins that determine the size of the molecules that can be filtrated by the kidneys.

In dogs, PLN can lead to a variety of symptoms, primarily related to the loss of protein and its effects on body functions. Symptoms may include fluid accumulation in the abdomen, skin, and limbs, and, ultimately, kidney failure. Also weight loss, weakness and lethargy, decreased appetite, vomiting or diarrhea, dehydration and increased (foamy) urine can be observed.

Dogs homozygous for the PLN-predisposing haplotype, and thus have the amino acid substitutions in both NPHS1 and KIRREL2, are at very high increased risk of developing PLN compared to dogs that are heterozygous or homozygous for the ‘‘normal’’ haplotype or alleles. Both the mutations in KIRREL2 and NPHS1 are tested in this combined test for PLN.