Four Evangelists – Matthew, Mark, Luke, and John
Four Doctors of Western Church – Saint Gregory the Great, Saint Ambrose, Saint Augustine, and Saint Jerome
Four Doctors of Eastern Church – Saint John Chrysostom, Saint Basil the Great, and Gregory of Nazianzus and Saint Athanasius
Four Galilean moons of Jupiter – Io, Europa, Ganymede, and Callisto
The Gang of Four was a Chinese communist political faction. The Fantastic Four: Mr. Fantastic, The Invisible Woman, The Human Torch, The Thing. The Teenage Mutant Ninja Turtles: Leonardo, Michelangelo, Donatello, Raphael
The Beatles were also known as the "Fab Four": John Lennon, Paul McCartney, George Harrison, Ringo Starr. Gang of Four is a British post-punk rock band formed in the late 1970s. Four rivers in the Garden of Eden (Genesis 2:10–14): Pishon (perhaps the Jaxartes or Syr Darya), Gihon (perhaps the Oxus or Amu Darya), Hiddekel (Tigris), and Prat (Euphrates). There are also four years in a single Olympiad (duration between the Olympic Games). Many major international sports competitions follow this cycle, among them the FIFA World Cup and its womens version, the FIBA World Championships for men and women, and the Rugby World Cup. There are four limbs on the human body. Four Houses of Hogwarts in the Harry Potter series: Gryffindor, Hufflepuff, Ravenclaw, Slytherin. Four known continents of the world in the A Song of Ice and Fire series: Westeros, Essos, Sothoryos, Ulthos. Each Grand Prix in Nintendos Mario Kart series is divided into four cups and each cup is divided into four courses.
Juvenile polyposis syndrome is an autosomal dominant genetic condition characterized by the appearance of multiple juvenile polyps in the gastrointestinal tract. Polyps are abnormal growths arising from a mucous membrane. These usually begin appearing before age 20, but the term juvenile refers to the type of polyp (i.e benign hamartoma, as opposed to adenoma for example), not to the age of the affected person. While the majority of the polyps found in juvenile polyposis syndrome are non-neoplastic, hamartomatous, self-limiting and benign, there is an increased risk of adenocarcinoma. Solitary juvenile polyps most commonly occur in the rectum and present with rectal bleeding. The World Health Organization criteria for diagnosis of juvenile polyposis syndrome are one of either:

More than five juvenile polyps in the colon or rectum; or
Juvenile polyps throughout the gastrointestinal tract; or
Any number of juvenile polyps in a person with a family history of juvenile polyposis. Signs and symptoms
Age of onset is variable. The term juvenile in the title of juvenile polyposis syndrome refers to the histological type of the polyps rather than the age of onset. Affected individuals may present with rectal bleeding, abdominal pain, diarrhea or anemia. On colonoscopy or sigmoidoscopy polyps that vary in shape or size are present. The polyps can be sessile or pedunculated hamartomatous polyps. Genetics
Juvenile polyposis syndrome can occur sporadically in families or be inherited in an autosomal dominant manner.Two genes associated with juvenile polyposis syndrome are BMPR1A and SMAD4.