biology

Samoyed hereditary glomerulopathy

Samoyed hereditary glomerulopathy is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Samoyed hereditary glomerulopathy rather than just read about it. In short: 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 in that the disease resembles that of the human disease.

Key takeaways

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Reference excerpt

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 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, and thus affects male dogs to a greater degree than female dogs, since males only have one X chromosome.

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. 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. 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.

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. 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 and ACE inhibitors, but not stopped or cured.

References

Further reading Thorner, P; Jansen, B; Baumal, R; Valli, VE; Goldberger, A (1987). "Samoyed hereditary glomerulopathy. Immunohistochemical staining of basement membranes of kidney for laminin, collagen type IV, fibronectin, and Goodpasture antigen, and correlation with electron microscopy of glomerular capillary basement membranes". Laboratory Investigation. 56 (4): 435–43. PMID 3550289. Jansen, B; Thorner, P; Baumal, R; Valli, V; Maxie, MG; Singh, A (1986). "Samoyed hereditary glomerulopathy (SHG). Evolution of splitting of glomerular capillary basement membranes". The American Journal of Pathology. 125 (3): 536–45. PMC 1888463. PMID 3799818. Rawdon, TG (2001). "Juvenile nephropathy in a Samoyed bitch". The Journal of Small Animal Practice. 42 (5): 235–8. doi:10.1111/j.1748-5827.2001.tb02027.x. PMID 11380016. Zheng, Keqin; Perry, Julie; Harvey, Scott J; Sado, Yoshikazu; Ninomiya, Yoshifumi; Jefferson, Barbara; Jacobs, Robert; Hudson, Billy G; Thorner, Paul S (2005). "Regulation of collagen type IV genes is organ-specific: Evidence from a canine model of Alport syndrome". Kidney International. 68 (5): 2121–30. doi:10.1111/j.1523-1755.2005.00668.x. PMID 16221211.

External links "Hereditary Nephritis-Samoyed Hereditary Glomerulopathy". VetGen. Retrieved 21 May 2011.

Illustrations

Worked examples

Example 1 — a first encounter with Samoyed hereditary glomerulopathy

Start with the simplest possible case. Write down what Samoyed hereditary glomerulopathy claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Samoyed hereditary glomerulopathy before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Samoyed hereditary glomerulopathy ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Samoyed hereditary glomerulopathy

In research: Samoyed hereditary glomerulopathy appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Samoyed hereditary glomerulopathy in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Samoyed hereditary glomerulopathy is common in secondary-school and first-year university syllabi. It links to neighbouring topics Autoimmune diseases, Genetic dog diseases, Glomerular diseases, so understanding it makes those chapters shorter.
In everyday life: Look for Samoyed hereditary glomerulopathy outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Samoyed hereditary glomerulopathy in 20 minutes

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Close the page and write down what Samoyed hereditary glomerulopathy means in your own words.
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Frequently asked questions

What is Samoyed hereditary glomerulopathy in simple terms?

Why does Samoyed hereditary glomerulopathy matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Samoyed hereditary glomerulopathy?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Samoyed hereditary glomerulopathy.