PharmaTimes talks to Emily McKechnie about the rare genetic disorder XLH and the Shine a Light on XLH campaign
What is XLH?
X-Linked Hypophosphataemia (XLH) is a rare genetic condition which affects our bones, teeth and muscles. This is caused by an excessive loss of phosphate in our urine, known as phosphate wasting. Having low phosphate causes the bones to weaken, which is commonly referred to as rickets. However, rickets can be cured, unlike XLH.
The consequences of having rickets include bone pain, short stature, legs bowing, hearing loss and stress fractures. Having weak bones can also affect the teeth by increasing the risk of abscesses and tooth loss.
Can you describe your path to diagnosis?
As a child, I was misdiagnosed with dwarfism. Between 2007 and 2010 I had two major surgeries to correct the bowing in my legs, which at the time the doctors believed was due to dwarfism. In my mid-teens, I was finally diagnosed with XLH. Unfortunately due to my age, I had outgrown the specialist children’s hospital and was transferred to my local hospital under endocrine care.
How did you come to terms with having a rare genetic disorder?
As most do, I googled XLH after I was diagnosed. After reading the symptoms, which matched up to my complications and short stature, I felt extremely overwhelmed and I cried with my mum. I have always wondered what my life would be like if I was diagnosed as a child; would I have a different future?; would I have needed those surgeries which cost me scars and a year out of education?
In the end, I have learned to love me despite the scars. Being vertically challenged has its perks, I fit into both children’s shoes (which are a lot cheaper) and clothes, as well as extra small to small adult clothes (which gives me much more variety).
What have you been told about your prognosis?
Unfortunately, there is no cure for XLH; it is a lifelong condition you have to adapt to living with. As you get older, the condition worsens, and symptoms begin to progress. Old age also increases the risk of mobility impairment, pain, osteoarthritis, stress fractures, hearing loss, dental problems and enthesopathy in people living with XLH. Recent research also suggests that XLH can reduce an individual’s life expectancy by eight years.1 For this reason, my XLH is monitored frequently to manage my medication and pain.
What treatment have you received?
The most common treatment for XLH requires supplementing the phosphate lost through oral therapy. I can’t tolerate this treatment, which has led to a quicker decline in my condition.
To manage my XLH, I regularly take phosphate supplements, which are dissolved in water to make a solution. I have to take these multiple times a day in order to try and maintain my phosphate levels. Alongside this, I take a high-dose calcitriol (vitamin D) tablet. However, the side effects and taste of these tablets make it intolerable to many individuals with XLH.
How does XLH affect your day-to-day life?
As a child, I didn’t have to take part in school sports, which I was happy about! My life felt normal until I became pregnant with my first daughter. During this pregnancy, aged 20, I felt myself start to decline.
The pain continued to increase, and I even started to struggle walking down the stairs. I shrugged this off due to being pregnant at the time. However, after my daughter was born, the pain continued. The pain, discomfort and stiffness I felt continued to worsen when I was pregnant with my second daughter, aged 22.
At the age of 24, I started to struggle going up the stairs, so my partner started to help me. The pain and the stiffness also tend to get worse in the evenings. For this reason, my partner now cooks tea for us all and helps me in and out of the shower. He also helps with the cleaning as my legs can get weak very fast. I feel like I am letting my family down as I struggle to care for them as much as I wish I could.
I work in retail and can only do a maximum of four hours per shift because of my XLH, and before every shift, I have to take pain relief. After a busy night shift in early August 2020, I was in more pain than usual. In particular, I felt a sharp pain in my upper left leg; I was later diagnosed via MRI scan with two stress fractures.
I rely on my friends, partner and family in my day-to-day life. I can’t walk very far due to the pain in my hips, legs and feet. Whilst shopping I struggle to reach the higher shelves. When I am alone, I have to ask for assistance which feels degrading. I get embarrassed every time I ask.
I have also had so many comments made by strangers asking why I am so short. I get my age mistaken and probably will do until I turn 40! I feel like I stick out in places like clubs and pubs. I get customers being rude and crude about my height, which happens nearly every shift. They make jokes and ask for my ID! I just laugh it off with them, but inside it hurts.
What would you say is the greatest challenge living with this disease?
My greatest challenge living with this condition is being aware of the decline in my mobility. What I could do three years ago, would cause me so much pain and discomfort now.
Both my dad and nana have this condition, so I have seen what happens when you get older with XLH. My dad struggles to get in and out of his car as he is so stiff, whilst my nana relies on her mobility scooter and stair lift in her house as she cannot weight-bear at all.
I worry that I will let my children down. Will they miss out on adventures because mummy is too sore? What if my children ever have to face bullying? Will they be able to live a normal life?
Are you satisfied with the medical care you have received in the UK?
For myself, I am not satisfied with the medical care that I have received.
I was misdiagnosed from childhood; this could have prevented the complications that occurred early in my life, such as leg bowing. I should have been on oral phosphate and vitamin D therapy from birth.
I was referred from a specialist children’s hospital to a general hospital, where they knew little about my condition. I had to do my own research and request to be seen by a specialist hospital for adults.
Dental care for adults with XLH in the UK is also inadequate. After multiple fillings, I am so insecure about my smile. I hate smiling with my teeth. I get seen by the dentist every six months, however, I feel like I need more care to maintain my teeth. I have to keep reminding them that I have XLH.
My children will get three-monthly check-ups, from both a specialist dentist and a local dentist. They will also get fluoride paste to protect their teeth. I wish I had this when I was their age.
Do you think the information available to the public on XLH is adequate?
Ten years ago, there was very little information around about XLH. I do believe this has improved. There is now more up-to-date research and websites, as well as support groups on social networks such as Facebook. I get to talk to other people with this condition, which has helped me emotionally. I don’t feel as alone. It is comforting to know that there are many other people that share this rare condition, not just my family.
Whilst technology improves, new research takes place and more treatment becomes available. I strongly believe that for the younger people living with XLH, the future is changing for the better. I just hope that my generation and older generations do not get forgotten about in the long run.
What advice would you give to someone newly diagnosed?
Do your research, look for specialist hospitals and dentists, and gain a strong multiple disciplinary team. Know that there are others just like you, who are on online support groups ready to listen to your struggles and give advice.
Medicine is always changing. Just try your best, listen to your doctors and take your medication. Without treatment for XLH, mobility decreases, pain increases and symptoms get worse.
Have you ever taken part in any clinical trials, if not – would you consider it?
I have never taken part in any clinical trials, but have always said to my doctors that if they know of any clinical trials, I will take part. If not for my future, then for my children’s.
What is your greatest hope and your greatest fear for the future?
My greatest hope is that a better treatment will become available for adults. Without this, I know that I will end up like my dad and Nana. Every day I think about losing my mobility and the affect this would have on myself and my family. My mobility is my independence and my sanity. I am only 25, and whilst I am confident for the future of my children, I am uncertain of my own.
What can you tell us about the Shine a Light on XLH campaign and why did you decide to take part?
The Shine a Light on XLH campaign is a creative and clever way to raise awareness about XLH. Phosphorus is also known for its glowing qualities and use in fireworks and matches. The campaign aims to harness the element’s illuminating properties through make-up to highlight the influential role it plays in XLH and to call for greater recognition and understanding of the disease.
I became aware of this campaign through a Facebook support group for XLH. I love to be an advocate and raise awareness; getting involved was easy for me, as XLH is me. I knew I needed to do whatever I could to raise awareness for my children. Diagnosis has already improved since I was born in 1995, as my children were diagnosed at birth. Their support is incredible.
I hope for adult care of XLH to be dealt with in the same manner as children’s, and for everyone suffering from XLH to have a strong multidisciplinary team. The perfect care team would include specialised endocrinologists and dentists, as well general local care from GPs, dentists and physiotherapists.
1 Hawley S, Shaw N, Delmestri A, Prieto-Alhambra D, Cooper C, Pinedo-Villanueva R et al. Prevalence and Mortality of Individuals With X-Linked Hypophosphatemia: A United Kingdom Real-World Data Analysis. The Journal of Clinical Endocrinology & Metabolism. 2019;105(3):e871-e878. https://doi.org/10.1210/clinem/dgz203