Rare Diseases: My teeth fall off easily and my bones are so hard walking breaks them

When Monica Nyaguthii Gitahi was born in 1987, the doctor’s noticed that her skull bone had not fully developed. They also noticed some abnormalities on her facial bone structure.

After running several tests on the newborn, they discovered she had a rare condition called pycnodysostosis, a genetic disorder characterised by distinctive facial features and skeletal malformations.

Individuals with this condition experience abnormal hardening of the bones as well as increased density that causes them to be brittle and fragile.

“There is no medication for my condition and I was asked to use crutches to avoid fractures in my bones when walking because they harden and break easily. I have had three fractures just by walking,” Monica tells My Health.

People with this condition also fail to grow and tend to be shorter than expected. For a 33-year-old, you would expect Monica to be about 5 ft 4 inches or thereabout.

“I am three and a half feet tall. My fingers and toes are short and have deformities,” she says.

According to Dr Anthony Muchiri Maina, an orthopaedic surgeon, the condition entails a genetic disorder in osteoclasts (the cells that are responsible for preventing excess build-up of bone).

“You end up with very dense (hard) bones that do not achieve maturity in quality (too hard hence brittle) and quantity (not long and not wide enough),” he explained.

The condition is caused by changes (mutations) in the cathepsin K (CTSK) gene and is inherited in an autosomal recessive trait, according to National Organisation for Rare Disorders (NORD), an organisation that researches on rare conditions.

“An infant’s skull has seven bones and several joints called sutures. Sutures are made of tough, elastic fibrous tissue and separate the bones from one another. Sutures meet up (intersect) at two spots on the skull called fontanelles, which are better known as an infant’s “soft spots”. The seven bones of an infant’s skull usually fuse together until around age two or later. In infants with pycnodysostosis, the sutures take longer to fuse together, which can affect the proper development of the skull. The skull is often larger than normal,” NORD says in its analysis.

Despite this being a genetic disorder, Monica says she is the only one in her nuclear and extended family with this condition.

Growing up was not an easy fit. She had to be in and out of hospital for surgeries to help manage the condition.

“My teeth also took long to develop and when they did, they were very few, approximately 10. They would fall off easily whenever I ate. I also experience a lot of pain in my feet. I cannot walk on rough surfaces. When it rains and the ground becomes slippery, I have to find someone to help me move about,” she says.

This condition is so rare it affects one in 1.7 million people globally.

Symptoms

According to Dr Muchiri, other symptoms of this condition include individuals with prominent front and back of the head. They may also have short fingers and small jaws.

“These individuals often experience teething problems. The milk (baby) teeth delay and the permanent teeth are irregular and may be missing.” he says.

“I have been advised by my doctor not to undertake any strenuous activities like walking without crutches or carrying heavy loads. I am also advised to ensure I eat a balanced diet to ensure my bones get the necessary nutrients to strengthen them,” Monica says.

Some people with this condition also develop bent spines, a condition known as kyphoscoliosis.

Dr Muchiri says that pycnodysostosis can typically be diagnosed at birth or infancy. However, genetic testing can be done to determine if both parents are carriers of the genetic defect. If both are carriers, there is a one in four chance of their children developing pycnodystosis.

Treatment

“There is currently no curative treatment - most entail treating the fractures. But there is genetic modification treatment that is underway to help mitigate the expression of the disease,” Dr Muchiri says.

Other forms of treatment may also include surgery, dental procedures and medications for pain.

“I have so far had two major surgeries, one was to remove an abscess that was growing in my anal area. Then I underwent yet another surgery to correct a condition I had developed called complex fistula,” Monica explains.

Her dental formula had to be replaced with artificial teeth that would not easily fall off or break.

“This was done last year when I was 32. At that time, I only had 10 teeth and they were very brittle. I had to have them all removed and replaced,” she says.  

Monica now lives in Naivasha where she runs her soap making business and encourages those with conditions that may threaten their normal way of lives.

“My parents and my siblings have never given up on me, they love me and support me in any way possible. In 2018, I started a group of people living with epilepsy, which I head as the chairperson under palliative care support group at Naivasha level Five hospital. We create awareness and touch life for those living with disability and vulnerable and already to give up we give hope for the future,” she says.