Treating Children

Treatment is evolving all the time, and the options available for children are far better than they used to be. With early diagnosis and appropriate care your child can thrive.

Monitoring bones and teeth in a growing child is an ongoing challenge, as is making the many routine appointments that they will need. There will be others in the XLH community with similar experiences and if you want to share your concerns they may have some useful advice.

Have you joined the XLH UK Facebook Group?

This is a private group for people interested in XLH, where all sorts of matters get aired and commented on.

A paediatric specialist who knows and understands the challenges posed by XLH can play an important role in your child’s care. He or she will be able to help your family get the treatment and the support needed.

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Treatment of Children

For Babies:

The manifestations of XLH exhibit significant variability and typically become apparent around eighteen months after birth.

In babies, you might observe an unusually elongated and narrow head shape (dolichocephaly), an increased front-to-back dimension of the skull (scaphocephaly), or premature fusion of skull bones (craniosynostosis).

In families where there is no history of XLH, the diagnosis journey can often be challenging. A diagnosis and treatment plan will be created once your baby is referred and seen by a paediatric endocrinologist.

For Children:

Burosumab is recommended for treating XLH in children with radiographic evidence of bone disease aged 1 year and over, and in young people with growing bones.

Burosumab was licensed in Europe in February 2018, with the National Institute for Health and Care Excellence in England first recommending the use in October 2018. Therefore, this can be prescribed on the NHS in England, Wales, Scotland, HSC in Northern Ireland and the NCPE in the Republic of Ireland. The prescription and treatment plan is managed by a paediatrician once the diagnosis is confirmed.

In people with XLH, the hormone fibroblast growth factor 23 (FGF23) is overactive, which signals to decrease the phosphate in the blood, resulting in poor bone mineralisation. Burosumab (marketed as Crysvita) is a monoclonal antibody that suppresses the activity of fibroblast growth factor 23 (FGF23). By suppressing FGF23, burosumab normalises the phosphate levels in the blood, which aids normalising bone mineralisation.

Burosumab is administered via subcutaneous injection, typically every 2-weeks for children. The British Paediatric and Adolescent Bone Group (BPABG) recommend that the starting dose is 0.4 mg/kg. After commencing treatment, blood phosphate levels are typically monitored every 2 weeks during the first month, every 4 weeks for the following 2 months and thereafter as appropriate. Treatment can begin in children aged 1 year and can continue until the bones stop growing.

Reference: Padidela R, Cheung MS, Saraff V, Dharmaraj P. Clinical guidelines for burosumab in the treatment of XLH in children and adolescents: British paediatric and adolescent bone group recommendations. Endocr Connect. 2020 Oct;9(10):1051-1056. doi: 10.1530/EC-20-0291. PMID: 33112809; PMCID: PMC7707830.

Transition from Paediatric to Adult Care

Transition between paediatric and adult care is the planned movement of young adults with chronic conditions from child-centred healthcare to adult-oriented systems. This process usually occurs between ages 14 and 18 to prepare patients and their families for the transfer of care. However, many XLH patients experience different levels of transition and face an uncoordinated transfer of care.

During this transition period, mental and emotional difficulties can arise, leading to confusion about care arrangements, especially when it coincides with major life changes like leaving home for work, university, or travel. Adult healthcare systems are often coordinated differently to paediatric care, requiring young-adult patients to take responsibility for accessing and managing their care from sometimes multiple specialists.

We recommend that young-adult patients take extra care to ensure that they remain in the NHS/HSE system once they are released from paediatric care.

XLH UK has collaborated on a proposed framework for a networked service model for care of adults with rare bone conditions