This is an inherited condition that presents hamartomatous polyps in the digestive tract. These are the noncancerous lesions of the normal tissue in the intestines and other places. The polyps may develop among individuals by the age of 20 and the total number of polyps can range from 5 to more than 100. Although these are the noncancerous lesions, it increases the risk of cancer of the digestive tract. This condition is estimated to affect around 1 in 16,000 to 1 in 100,000 individuals.
Causes
This syndrome occurs as the result of a mutation in the BMPR1A and SMAD4 genes which are responsible for the production of proteins that are important in transmitting chemical signals from the cell membrane to the nucleus. These two genes regulate the activity of various genes and the growth and division of cells. The genetic mutation affects the normal cellular signaling and disrupting their roles in regulating gene activity. This is inherited in an autosomal dominant pattern meaning one copy of the defective gene can cause this syndrome. Around 75% of the cases are the result of inheriting the genetic mutation and the remaining 25% develops as the result of new genetic mutation.
Symptoms
Some of the affected individuals may present no symptoms. If the polyps are large and numerous, some of the associated symptoms can include constipation, abdominal pain, diarrhea, chronic weight loss, anemia, bleeding from the rectum and blood in the stool. This syndrome is usually suspected in cases when more than 5 juvenile polyps of the rectum or the colon are present, when multiple polyps are evident in the digestive tract or when any numbers of these polyps appear with the family history of this condition.
Diagnosis
The diagnosis is based on the symptoms and the prevalence of this disorder in the family. The genetic test can identify the mutation in the genes responsible for causing this condition. A negative genetic test does not rule out the diagnosis of this condition as other genes associated with this syndrome have not yet been identified. Hence, individuals with the history of this condition in the family or with the symptoms of this syndrome are recommended to seek medical evaluation with the genetic counselor or medical geneticist. A complete blood count, colonoscopy and an upper endoscopy are important if the symptoms are evident and should be repeated every few years depending on the number of polyps evident.
Treatment
If only a few polyps are detected, this can usually be removed during the endoscopic examination. If large numbers of polyps are evident, a procedure to remove a part of the stomach and the intestine is recommended. The most important aspects of the treatment include screening and continuous monitoring of the symptoms among the affected individuals.
References
http://www.cancer.net/cancer-types/juvenile-polyposis-syndrome
https://ghr.nlm.nih.gov/condition/juvenile-polyposis-syndrome#inheritance
