A varus deformity is an excessive inward angulation (medial angulation, that is, towards the bodys midline) of the distal segment of a bone or joint. The opposite of varus is called valgus. EX: Varus deformity results in a decreased Q angle of the knee joint. The terms varus and valgus always refer to the direction that the distal segment of the joint points. For example, in a valgus deformity of the knee, the distal part of the leg below the knee is deviated outward, in relation to the femur, resulting in a knock-kneed appearance. Conversely, a varus deformity at the knee results in a bowlegged  with the distal part of the leg deviated inward, in relation to the femur. However, in relation to the mid-line of the body, the knee joint is deviated towards the mid-line. EX: Valgus deformity results in an increased Q angle of the knee joint. Terminology
The terminology is made confusing by the etymology of these words. The terms varus and valgus are both Latin, but confusingly, their Latin meanings conflict with their current usage. In current usage, as noted above, a varus deformity of the knee describes bowed legs, but in the original Latin, varus meant "knock-kneed."
Cause
Gardner syndrome is caused by mutation in the adenomatous polyposis coli (APC gene), located in chromosome 5q21 (band q21 on chromosome 5). This gene is also mutant in familial adenomatous polyposis (FAP), a more common disease that also predisposes to colon cancer. Nuances in the understanding of genetics have caused some disorders to be split into multiple entities, while others merged into one genetic condition. After most of the second half of the 20th century, Gardner syndrome has been merged into FAP and is now considered simply a phenotypic subtype of FAP. FAP defined by the development of hundreds or thousands of polyps in the colon. Gardner syndrome is set apart as a subtype because, in addition to colonic polyps, there are also extra-colonic growths (both malignant and benign). There are many terms used to describe "APC-associated polyposis condition" including FAP, attenuated FAP, Gardner syndrome, Turcot syndrome, and gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). There is a movement toward no longer using the terms Gardner Syndrome or Turcot Syndrome since both are part of the FAP spectrum. Gardner syndrome and Turcot syndrome are regarded primarily for historical interest. Genetics
Gardner syndrome is inherited in an autosomal dominant manner. Typically, one parent has Gardner syndrome. Each of their children, male and female alike, are at 50% risk of inheriting the gene for Gardner syndrome. Diagnosis
Gardner syndrome consists of adenomatous polyps of the gastrointestinal tract, Gardner fibromas, desmoid tumors, osteomas, epidermoid cysts, lipomas, dental abnormalities, and periampullary carcinomas.