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Category: About XLH

What is XLH?

X-linked hypophosphatemia (XLH) is a rare condition, so it’s possible you've not heard of it before. Find out about XLH on this website, starting here.

Causes of XLH

A simple genetic change on the X-chromosome causes your body to produce too much fibroblast growth factor 23 (FGF23) – a hormone involved in phosphate control.

Why genes matter

XLH can happen spontaneously but, if it runs in your family, this section helps to explain how it's passed on from parent to child.


Diagnosis of XLH usually happens in childhood, but can happen in infancy and adulthood too. Here's what to expect.

Childhood XLH symptoms

If you or another family member has XLH, you’re likely to know which symptoms to look out for. However, if no one else in your family has XLH, it may be harder to spot.

Adult XLH symptoms

XLH symptoms vary from person to person. However, there are a number of symptoms to look out for that affect many adults with XLH.

Top 10 facts

Being diagnosed with XLH is the beginning of a journey. With the right knowledge and support many people learn to manage their condition without it managing them.

Diagnosis checklist

If you think your child might be affected by XLH it's worth finding out about possible signs and symptoms before talking to your healthcare team.

XLH Link - HCP Website

This Kyowa Kirin website is intended for Healthcare Professionals (HCPs) involved in the care of people with X-linked Hypophosphatemia (XLH).

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