Samoyed hereditary glomerulopathy

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Healthy Samoyed dog Shuskey.jpg
Healthy Samoyed dog

Samoyed hereditary glomerulopathy (SHG) is a hereditary, X-linked, noninflammatory disease of the renal glomeruli, occurring in the Samoyed breed of dog. The disease has been shown to be a model for Alport syndrome in humans [1] 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, the trait is inherited as a sex-linked, genetically dominant disease, [2] and thus affects male dogs to a greater degree than female dogs, since males only have one X chromosome.

Contents

Description

SHG is caused by a nonsense mutation in codon 1027 of the COL4A5 gene on the X chromosome (glycine to stop codon), which is similar to Alport syndrome in humans. [3] The disease is simply inherited, X-linked dominant, 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, kidney 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. [4] [5]

The disease is specific to the Samoyed, in that the Samoyed is the only breed of dog to show the more rapid progression to kidney 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. Proteinuria has been found consistently in Samoyeds, Doberman Pinschers, and Cocker spaniels. [6] [7]

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 and hypoalbuminemia. Past nine months of age, hypercholesterolemia may be seen. [1] In the final stages of the disease, at around 15 months of age for affected males, symptoms are reported as being kidney failure, hearing loss and death. Since the condition is genetically dominant, 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 [5] and ACE inhibitors, but not stopped or cured. [8]

Related Research Articles

<span class="mw-page-title-main">Samoyed dog</span> Dog breed

The Samoyed is a breed of medium-sized herding dogs with thick, white, double-layer coats. They are spitz-type dogs which take their name from the Samoyedic peoples of Siberia. Descending from the Nenets Herding Laika, they are domesticated animals that assist in herding, hunting, protection and sled-pulling.

<span class="mw-page-title-main">Kidney disease</span> Damage to or disease of a kidney

Kidney disease, or renal disease, technically referred to as nephropathy, is damage to or disease of a kidney. Nephritis is an inflammatory kidney disease and has several types according to the location of the inflammation. Inflammation can be diagnosed by blood tests. Nephrosis is non-inflammatory kidney disease. Nephritis and nephrosis can give rise to nephritic syndrome and nephrotic syndrome respectively. Kidney disease usually causes a loss of kidney function to some degree and can result in kidney failure, the complete loss of kidney function. Kidney failure is known as the end-stage of kidney disease, where dialysis or a kidney transplant is the only treatment option.

<span class="mw-page-title-main">Alport syndrome</span> Medical condition

Alport syndrome is a genetic disorder affecting around 1 in 5,000–10,000 children, characterized by glomerulonephritis, end-stage kidney disease, and hearing loss. Alport syndrome can also affect the eyes, though the changes do not usually affect vision, except when changes to the lens occur in later life. Blood in urine is universal. Proteinuria is a feature as kidney disease progresses.

<span class="mw-page-title-main">Podocyte</span> Type of kidney cell

Podocytes are cells in Bowman's capsule in the kidneys that wrap around capillaries of the glomerulus. Podocytes make up the epithelial lining of Bowman's capsule, the third layer through which filtration of blood takes place. Bowman's capsule filters the blood, retaining large molecules such as proteins while smaller molecules such as water, salts, and sugars are filtered as the first step in the formation of urine. Although various viscera have epithelial layers, the name visceral epithelial cells usually refers specifically to podocytes, which are specialized epithelial cells that reside in the visceral layer of the capsule.

<span class="mw-page-title-main">Glomerulonephritis</span> Term for several kidney diseases

Glomerulonephritis (GN) is a term used to refer to several kidney diseases. Many of the diseases are characterised by inflammation either of the glomeruli or of the small blood vessels in the kidneys, hence the name, but not all diseases necessarily have an inflammatory component.

<span class="mw-page-title-main">X-linked recessive inheritance</span> Mode of inheritance

X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be always expressed in males and in females who are homozygous for the gene mutation, see zygosity. Females with one copy of the mutated gene are carriers.

<span class="mw-page-title-main">Membranous glomerulonephritis</span> Kidney disease

Membranous glomerulonephritis (MGN) is a slowly progressive disease of the kidney affecting mostly people between ages of 30 and 50 years, usually white people.

<span class="mw-page-title-main">Nephritic syndrome</span> Symptoms resulting from kidney inflammation

Nephritic syndrome is a syndrome comprising signs of nephritis, which is kidney disease involving inflammation. It often occurs in the glomerulus, where it is called glomerulonephritis. Glomerulonephritis is characterized by inflammation and thinning of the glomerular basement membrane and the occurrence of small pores in the podocytes of the glomerulus. These pores become large enough to permit both proteins and red blood cells to pass into the urine. By contrast, nephrotic syndrome is characterized by proteinuria and a constellation of other symptoms that specifically do not include hematuria. Nephritic syndrome, like nephrotic syndrome, may involve low level of albumin in the blood due to the protein albumin moving from the blood to the urine.

Thin basement membrane disease is, along with IgA nephropathy, the most common cause of hematuria without other symptoms. The only abnormal finding in this disease is a thinning of the basement membrane of the glomeruli in the kidneys. Its importance lies in the fact that it has a benign prognosis, with patients maintaining a normal kidney function throughout their lives.

<span class="mw-page-title-main">Nail–patella syndrome</span> Medical condition

Nail–patella syndrome is a genetic disorder that results in small, poorly developed nails and kneecaps, but can also affect many other areas of the body, such as the elbows, chest, and hips. The name "nail–patella" can be very misleading because the syndrome often affects many other areas of the body, including even the production of certain proteins. The severity of these effects varies depending on the individual. It is also referred to as iliac horn syndrome, hereditary onychoosteodysplasia, Fong disease or Turner–Kieser syndrome.

<span class="mw-page-title-main">Glomerular basement membrane</span> Part of the filtration apparatus of the kidney

The glomerular basement membrane of the kidney is the basal lamina layer of the glomerulus. The glomerular endothelial cells, the glomerular basement membrane, and the filtration slits between the podocytes perform the filtration function of the glomerulus, separating the blood in the capillaries from the filtrate that forms in Bowman's capsule. The glomerular basement membrane is a fusion of the endothelial cell and podocyte basal laminas, and is the main site of restriction of water flow. Glomerular basement membrane is secreted and maintained by podocyte cells.

<span class="mw-page-title-main">Dent's disease</span> Medical condition

Dent's disease is a rare X-linked recessive inherited condition that affects the proximal renal tubules of the kidney. It is one cause of Fanconi syndrome, and is characterized by tubular proteinuria, excess calcium in the urine, formation of calcium kidney stones, nephrocalcinosis, and chronic kidney failure.

<span class="mw-page-title-main">Collagen, type IV, alpha 5</span> Protein-coding gene in humans

Collagen alpha-5(IV) chain is a protein that in humans is encoded by the COL4A5 gene.

<span class="mw-page-title-main">Collagen, type IV, alpha 1</span> Protein found in humans

Collagen alpha-1(IV) chain (COL4A1) is a protein that in humans is encoded by the COL4A1 gene on chromosome 13. It is ubiquitously expressed in many tissues and cell types. COL4A1 is a subunit of the type IV collagen and plays a role in angiogenesis. Mutations in the gene have been linked to diseases of the brain, muscle, kidney, eye, and cardiovascular system. The COL4A1 gene also contains one of 27 SNPs associated with increased risk of coronary artery disease.

<span class="mw-page-title-main">Collagen, type IV, alpha 4</span> Protein found in humans

Collagen alpha-4(IV) chain is a protein that in humans is encoded by the COL4A4 gene.

<span class="mw-page-title-main">Mesangial proliferative glomerulonephritis</span> Medical condition

Mesangial proliferative glomerulonephritis (MesPGN) is a morphological pattern characterized by a numerical increase in mesangial cells and expansion of the extracellular matrix within the mesangium of the glomerulus. The increase in the number of mesangial cells can be diffuse or local and immunoglobulin and/or complement deposition can also occur. MesPGN is associated with a variety of disease processes affecting the glomerulus, though can be idiopathic. The clinical presentation of MesPGN usually consists of hematuria or nephrotic syndrome. Treatment is often consistent with the histologic pattern of and/or disease process contributing to mesangial proliferative glomerulonephritis, and usually involves some form of immunosuppressant.

Glomerulopathy is diseases that impact the glomeruli in the nephron, either inflammatory or noninflammatory. Glomerulopathy includes collapsing glomerulopathy, glomerulocystic kidney disease, glomerulomegaly, membranous nephropathy, and tip lesion glomerulopathy.

Glomerulonephrosis is a non-inflammatory disease of the kidney (nephrosis) presenting primarily in the glomerulus as nephrotic syndrome. The nephron is the functional unit of the kidney and it contains the glomerulus, which acts as a filter for blood to retain proteins and blood lipids. Damage to these filtration units results in important blood contents being released as waste in urine. This disease can be characterized by symptoms such as fatigue, swelling, and foamy urine, and can lead to chronic kidney disease and ultimately end-stage renal disease, as well as cardiovascular diseases. Glomerulonephrosis can present as either primary glomerulonephrosis or secondary glomerulonephrosis.

Diffuse proliferative glomerulonephritis (DPGN) is a type of glomerulonephritis that is the most serious form of renal lesions in SLE and is also the most common, occurring in 35% to 60% of patients. In absence of SLE, DPGN pathology looks more like Membranoproliferative glomerulonephritis

<span class="mw-page-title-main">Epstein syndrome</span> Medical condition

Epstein syndrome is a rare genetic disease characterized by a mutation in the MYH9 gene in nonmuscle myosin. This disease affects the patient's renal system and can result in kidney failure. Epstein syndrome was first discovered in 1972 when two families had similar symptoms to Alport syndrome. Epstein syndrome and other Alport-like disorders were seen to be caused by mutations in the MYH9 gene, however, Epstein syndrome differs as it was more specifically linked to a mutation on the R702 codon on the MYH9 gene. Diseases with mutations on the MYH9 gene also include May–Hegglin anomaly, Sebastian syndrome and Fechtner syndrome.

References

  1. 1 2 Jansen, B; Valli, VE; Thorner, P; Baumal, R; Lumsden, JH (1987). "Samoyed hereditary glomerulopathy: serial, clinical and laboratory (urine, serum biochemistry and hematology) studies". Canadian Journal of Veterinary Research. 51 (3): 387–93. PMC   1255344 . PMID   3651895.
  2. Jansen, B; Tryphonas L; Wong J; Thorner P; Maxie MG; Valli VE; Baumal R; Basrur PK. (June 1986). "Mode of inheritance of Samoyed hereditary glomerulopathy: an animal model for hereditary nephritis in humans". J Lab Clin Med. (6). 107 (6): 551–5. PMID   3711721.
  3. Jansen, B; Tryphonas, L; Wong, J; Thorner, P; Maxie, MG; Valli, VE; Baumal, R; Basrur, PK (1986). "Mode of inheritance of Samoyed hereditary glomerulopathy: an animal model for hereditary nephritis in humans". The Journal of Laboratory and Clinical Medicine. 107 (6): 551–5. PMID   3711721.
  4. Zheng, K; Thorner, PS; Marrano, P; Baumal, R; McInnes, RR (1994). "Canine X chromosome-linked hereditary nephritis: a genetic model for human X-linked hereditary nephritis resulting from a single base mutation in the gene encoding the alpha 5 chain of collagen type IV". Proceedings of the National Academy of Sciences of the United States of America. 91 (9): 3989–93. Bibcode:1994PNAS...91.3989Z. doi: 10.1073/pnas.91.9.3989 . PMC   43708 . PMID   8171024.
  5. 1 2 Chen, D.; Jefferson, B; Harvey, SJ; Zheng, K; Gartley, CJ; Jacobs, RM; Thorner, PS (2003). "Cyclosporine A Slows the Progressive Renal Disease of Alport Syndrome (X-Linked Hereditary Nephritis): Results from a Canine Model". Journal of the American Society of Nephrology. 14 (3): 690–8. doi: 10.1097/01.ASN.0000046964.15831.16 . PMID   12595505.
  6. Wilcock, BP; Patterson, JM (1979). "Familial glomerulonephritis in Doberman pinscher dogs". The Canadian Veterinary Journal. 20 (9): 244–9. PMC   1789598 . PMID   498006.
  7. Steward, A. P.; MacDougall, D. F. (1984). "Familial nephropathy in the Cocker Spaniel". Journal of Small Animal Practice. 25: 15–24. doi:10.1111/j.1748-5827.1984.tb00475.x.
  8. Grodecki, K; Gains, M; Baumal, R; Osmond, D; Cotter, B; Valli, V; Jacobs, R (1997). "Treatment of X-linked hereditary nephritis in samoyed dogs with angiotensin converting enzyme (ACE) inhibitor". Journal of Comparative Pathology. 117 (3): 209–25. doi:10.1016/S0021-9975(97)80016-3. PMID   9447482.

Further reading