FGF23related

FGF23related refers to a group of rare genetic disorders caused by mutations in the FGF23 gene. Fibroblast growth factor 23 (FGF23) is a hormone that plays a crucial role in regulating phosphate and vitamin D metabolism. When the FGF23 gene is mutated, it can lead to either an overproduction or an underproduction of the FGF23 protein, disrupting these vital processes.

There are two main types of FGF23related disorders. Tumoral calcinosis (TC) is characterized by the excessive production of FGF23, leading to hyperphosphatemia (high phosphate levels in the blood) and hypophosphatemia (low phosphate levels in the urine). This results in the formation of calcified masses, often around joints, which can cause pain and restrict movement. Other symptoms can include joint stiffness, skin nodules, and sometimes inflammation.

X-linked hypophosphatemic rickets (XLH) and autosomal recessive hypophosphatemic rickets (ARH) are characterized by insufficient or ineffective FGF23 signaling, leading to hypophosphatemia and impaired bone mineralization. This results in rickets in children, characterized by soft and weak bones, leading to skeletal deformities such as bowed legs. In adults, it can cause osteomalacia, a condition of bone softening. Both XLH and ARH can lead to short stature, bone pain, and dental problems.

Diagnosis of FGF23related disorders typically involves measuring serum phosphate, calcium, alkaline phosphatase, and FGF23 levels, along with genetic testing to identify mutations in the FGF23 gene. Treatment strategies aim to manage phosphate levels, promote bone mineralization, and alleviate symptoms, often involving phosphate and vitamin D supplementation, and in some cases, medication to inhibit FGF23 activity. Research into new therapies is ongoing.