SNP Shot: Genomic Insights

Hyperphosphatemic familial tumoral calcinosis (HFTC) is a disorder marked by elevated phosphate levels in the bloodstream (hyperphosphatemia) and the formation of abnormal phosphate and calcium deposits (calcinosis) within the body's tissues. While calcinosis commonly emerges from early childhood through early adulthood, some individuals experience their initial deposits during infancy or later in adulthood. Calcinosis typically affects the skin and underlying tissues around joints, frequently the hips, shoulders, and elbows. It can also affect the soft tissues of the feet, legs, and hands. In rare instances, calcinosis may occur in blood vessels or the brain, leading to potentially severe health complications. These deposits develop gradually and vary in size. Larger deposits can create noticeable masses beneath the skin, hindering joint function and restricting movement. Although these larger deposits may resemble tumors (tumoral), they are not actual tumors or cancerous growths. The quantity and frequency of these deposits differ among individuals; some develop only a few deposits throughout their lives, while others may develop numerous deposits rapidly.

Additional characteristics of HFTC include eye problems like calcium deposits on the cornea (corneal calcification) or angioid streaks, which are caused by small tears in Bruch's membrane, a tissue layer at the back of the eye. Inflammation of the long bones (diaphyseal inflammation) or excessive bone growth (hyperostosis) may also be present. Some individuals with HFTC exhibit dental irregularities. In males, the accumulation of tiny cholesterol crystals (microlithiasis) in the testicles can occur, though it usually doesn't cause any health issues.

Hyperphosphatemia-hyperostosis syndrome (HHS), a similar condition, also involves elevated phosphate levels in the blood, excessive bone growth, and bone lesions. Previously considered a separate disorder, HHS is now recognized as a milder form of HFTC.

Inheritance:

HFTC follows an autosomal recessive inheritance pattern. This means that an affected individual must inherit a mutated copy of the responsible gene from each parent. The parents, who each carry only one copy of the mutated gene, usually do not exhibit any signs or symptoms of the condition.