Samoyed hereditary glomerulopathy
Encyclopedia
In canines, Samoyed hereditary glomerulopathy [glo-mer″u-lop´ah-the] (SHG) is an hereditary noninflammatory disease, of the renal glomeruli occurring in the Samoyed breed of dog. The disease has been shown to be a model for hereditary nephritis (HN) in humans in that the disease resembles that of the human disease. Because of this, it is sometimes referred to by the name given to the disease in humans when referring to the conditions in Samoyed dogs. Alternatively, it may also be known as X-linked hereditary nephritis. Genetically, it is a sex-linked, genetically recessive disease, and thus affects male dogs to a greater degree than female dogs, since males only have one X chromsome.
in codon 1027 of the COL4A5 gene on the X chromosome
(glycine
to stop codon
), which is similar to Alport's syndrome in humans. The disease is simply inherited, X-linked recessive, with males generally having more severe symptoms than females. Clinically, from the age of three to four months, proteinuria
in both sexes is seen. In dogs older than this, renal failure in combination with more or less pronounced hearing loss occurs swiftly, and death at the age of 8 to 15 months is expected. In heterozygous females, whereby only one of the two X chromosomes carry the mutation, the disease develops slowly.
The disease is specific to the Samoyed in that, the Samoyed, is the only breed of dog to show the more rapid progression to renal failure and death, as well as affecting males to a much more severe degree than females. The Samoyed, however is not the only breed of dog to suffer from life threatening renal diseases. Protienuria has been found consistently in Samoyed
s, Doberman Pinschers, and Cocker spaniels.
s, but not stopped or cured.
Description
Samoyed Hereditary Glomerulopathy is caused by a nonsense mutationNonsense mutation
In genetics, a nonsense mutation is a point mutation in a sequence of DNA that results in a premature stop codon, or a nonsense codon in the transcribed mRNA, and in a truncated, incomplete, and usually nonfunctional protein product. It differs from a missense mutation, which is a point mutation...
in codon 1027 of the COL4A5 gene on the X chromosome
X chromosome
The X chromosome is one of the two sex-determining chromosomes in many animal species, including mammals and is common in both males and females. It is a part of the XY sex-determination system and X0 sex-determination system...
(glycine
Glycine
Glycine is an organic compound with the formula NH2CH2COOH. Having a hydrogen substituent as its 'side chain', glycine is the smallest of the 20 amino acids commonly found in proteins. Its codons are GGU, GGC, GGA, GGG cf. the genetic code.Glycine is a colourless, sweet-tasting crystalline solid...
to stop codon
Stop codon
In the genetic code, a stop codon is a nucleotide triplet within messenger RNA that signals a termination of translation. Proteins are based on polypeptides, which are unique sequences of amino acids. Most codons in messenger RNA correspond to the addition of an amino acid to a growing polypeptide...
), which is similar to Alport's syndrome in humans. The disease is simply inherited, X-linked recessive, with males generally having more severe symptoms than females. Clinically, from the age of three to four months, proteinuria
Proteinuria
Proteinuria means the presence of anexcess of serum proteins in the urine. The protein in the urine often causes the urine to become foamy, although foamy urine may also be caused by bilirubin in the urine , retrograde ejaculation, pneumaturia due to a fistula, or drugs such as pyridium.- Causes...
in both sexes is seen. In dogs older than this, renal failure in combination with more or less pronounced hearing loss occurs swiftly, and death at the age of 8 to 15 months is expected. In heterozygous females, whereby only one of the two X chromosomes carry the mutation, the disease develops slowly.
The disease is specific to the Samoyed in that, the Samoyed, is the only breed of dog to show the more rapid progression to renal failure and death, as well as affecting males to a much more severe degree than females. The Samoyed, however is not the only breed of dog to suffer from life threatening renal diseases. Protienuria has been found consistently in Samoyed
Samoyed (dog)
The Samoyed dog takes its name from the Samoyedic peoples of Siberia. An alternate name for the breed, especially in Europe, is Bjelkier...
s, Doberman Pinschers, and Cocker spaniels.
Diagnosis
Affected male and carrier female dogs generally begin to show signs of the disease at two to three months of age, with proteinuria. By three to four months of age, symptoms include for affected male dogs: bodily wasting and loss of weight, proteinuria & hypoalbuminemia. Past nine months of age, hypercholesterolemia may be seen. In the final stages of the disease, at around 15 months of age for affected males, symptoms are reported as being renal failure, hearing loss and death. Since the condition is genetically recessive, diagnosis would also include analysis of the health of the sire and dam of the suspected affected progeny if available.Treatment
The disease can be treated only to slow down the development, by use of cyclosporine A and ACE inhibitorACE inhibitor
ACE inhibitors or angiotensin-converting enzyme inhibitors are a group of drugs used primarily for the treatment of hypertension and congestive heart failure...
s, but not stopped or cured.