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Lundehund Syndrome (LS)
| Acronym: | LS |
| Gene: | P3H2 (LEPREL1) |
| Mutation: | c.1849G>C |
| Inheritance: | Autosomal recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Lundehund syndrome (LS) is an inherited gastoenteropathy affecting the Lundehund dog breed. The disorder is also known as the Lundehund intestinal syndrome and it is a combination of stomach and intestinal diseases which cause malabsorption and protein loss and deficiency. The Norwegian Lundehund, also known as the puffin dog has experienced a severe bottleneck, with only five remaining dogs in the 1960s. The bottleneck resulted in the high widespread of the LS causative mutation in today’s Lundehund dogs. A similar condition has been recognized in the Soft Coated Wheaten Terrier, known as Protein Losing Nephropathy, which is affecting their immune system, gut, and kidney.
The Lundehund syndrome comprises several disorders together: protein-losing enteropathy (PLE), intestinal lymphangiectasia, gastrointestinal disturbance, inflammatory bowel disease, and malabsorption. The first symptoms start to appear between 2.5 to 10.5 years of age. Clinical signs include diarrhea, vomiting, loss of appetite, weight loss, edema, swollen abdomen and/or swollen legs, low serum protein, especially albumin, and apathy. Low levels of albumin are sometimes the only sign of the disorder. Hypoalbuminemia is sometimes accompanied by hyperglobulinaemia, reduced levels of fructosamines and vitamin B, hypo- or hypercalcemia, as well as high levels of serum folate and alanine aminotransferase. The condition can eventually lead to lymphoma or cancer of the intestines or stomach. Often, Lundehuns who appear healthy, show abnormal findings in histopathologic examinations.
The Lundehund syndrome (LS) is caused by a mutation in the neuropeptide operating gene LEPREL1. During the research, some Lundehund dogs showed no symptoms of the disorder although carrying two alleles of the causative mutation. Lundehunds without clinical signs for LS who carry the causative mutation are expected to be subclinically affected or fall ill later in their life by specific trigger mechanisms. The onset of the disease could be also influenced by external factors, which trigger the phenotypic expressions. The Lundehund syndrome is inherited as an autosomal recessive disorder. Healthy parents of an affected dog are obligate heterozygotes and therefore carry one mutant allele. Heterozygotes have no symptoms. At conception, each cub has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier.
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:
Metzger, J., Pfahler, S., & Distl, O. (2016). Variant detection and runs of homozygosity in next generation sequencing data elucidate the genetic background of Lundehund syndrome. BMC Genomics, 17, 535. http://doi.org/10.1186/s12864-016-2844-6