Hypophosphatemic Rickets (XLH)
Description
Hypophosphatemic rickets (XLH) is a rare genetic disorder that affects bone growth and development. This condition causes the body to have low levels of phosphate, a vital mineral for healthy bones. It can lead to various skeletal deformities and complications if left untreated. Learn more about XLH, including its symptoms, causes, diagnosis, management, and how to thrive with this condition.
Genes Involved
Genes Involved in Hypophosphatemic Rickets (XLH):
XLH is caused by mutations in the PHEX gene. The PHEX gene provides instructions for making an enzyme called phosphate-regulating gene with homologies to endopeptidases on the X chromosome. This enzyme plays a crucial role in regulating phosphate levels in the body. Mutations in the PHEX gene disrupt the normal function of this enzyme, leading to low phosphate levels in the blood and the development of XLH.
Recognizing the Signs and Symptoms
Recognizing the Signs and Symptoms of Hypophosphatemic Rickets (XLH):
- Delayed Bone Growth: Children with XLH may experience delayed bone growth, resulting in short stature.
- Bone Deformities: The disorder can lead to various bone deformities, including bowlegs, knock-knees, and curvature of the spine.
- Fractures: Bones may be weaker and more prone to fractures.
- Dental Problems: Dental enamel may be thin and weak, leading to cavities and tooth decay.
- Muscle Weakness: Some individuals with XLH may experience muscle weakness and fatigue.
- Pain and Stiffness: Bone pain and joint stiffness are common symptoms.
- Waddling Gait: Individuals may walk with a waddling gait due to leg deformities.
If you notice any of these signs or symptoms in yourself or your child, it‘s crucial to consult with a healthcare professional for prompt diagnosis and management.
Causes
Causes of Hypophosphatemic Rickets (XLH):
XLH is a genetic disorder caused by mutations in the PHEX gene. This gene is located on the X chromosome, meaning it is an X-linked dominant condition. This means that a single copy of the mutated gene is sufficient to cause the disorder. The mutations in the PHEX gene lead to a deficiency in the enzyme responsible for regulating phosphate levels. The lack of this enzyme causes the kidneys to excrete excessive amounts of phosphate, resulting in low phosphate levels in the blood.
In some cases, XLH can also be caused by a new mutation, meaning it occurs for the first time in an individual and is not inherited from their parents.
Inheritance/recurrence risk
Inheritance and Recurrence Risk of Hypophosphatemic Rickets (XLH):
XLH is an X-linked dominant disorder. This means that if a parent has the mutated gene, there‘s a 50% chance that their child will inherit it. If a male inherits the mutated gene, they will develop XLH. If a female inherits the mutated gene, she may or may not develop XLH, depending on the specific mutation and other factors.
If a female with XLH has children, there is a 50% chance that each of her sons will inherit the condition. Her daughters have a 50% chance of inheriting the mutated gene. Since XLH is an X-linked dominant disorder, the risk of recurrence is high in families with a history of the condition.
