Last updated July 2018
By Sarah Foye
Adam is a 17-year-old from New Jersey, USA. He has been diagnosed with autosomal
recessive centronuclear myopathy, also known as congenital titinopathy, which is caused by variants in the Titin (TTN) gene. Titin is a protein located in muscle cells, and it’s massive; in fact, it’s the largest protein in nature.
Operating in the muscles’ sarcomere, it provides the cells with structural support and the ability to move by contracting and relaxing like a spring. It’s particularly important for ensuring the muscle’s normal ‘elasticity’: after your muscle does the work of contracting, the Titin protein helps it stretch back to its resting position. Disease-causing variants in the Titin gene can cause a spectrum of muscle and heart disorders, including centronuclear myopathy, like in Adam’s case.
Adam had a normal birth and was a healthy infant. But we soon noticed that he was not meeting his motor milestones like a typical child (e.g. lifting his head, rolling, etc). By six months old, several doctors and therapists evaluated him and it was suspected that he had some type of myopathy (muscle disorder).
At 13 months old he had a muscle biopsy that confirmed the diagnosis of myotubular myopathy (MTM). We even had the muscle slides sent to another hospital for a second expert opinion, which agreed.
Next, Adam had the genetic test for MTM1 at the University of Chicago. Although most boys with MTM test positive for this mutation, Adam did not. Thus, it is assumed that he had the autosomal recessive form, rather than the X-linked form. Adam started walking (very wobbly) at 15 months of age. He never crawled because he did not have the head/upper body strength to do so. It was clear though that there was nothing wrong with his mind – as he was always learning new words at a very precocious rate. It was because of his biopsy results, his negative MTM1 test and his milder severity of deficits that the doctors gave him the diagnosis of autosomal recessive CNM.
Adam attended regular, mainstream school with a nurse on hand for when he was sick and took his medical challenges in his stride. Around four years old, Adam developed scoliosis (sideways curving of the spine), which continued to worsen and at age six, he started on a ventilator (breathing machine) at night to treat hypoventilation (not breathing well enough) which occurs when he sleeps. When he has a respiratory infection (e.g. a head cold or bronchitis), he uses a Cough Assist machine to suck out secretions from his lungs, to prevent pneumonia. He has never been intubated nor had a tracheostomy.
As his parents, we are so proud of him and how much progress he has made. Today Adam continues to attend a regular mainstream school with a nurse on-hand for help with medical issues. He splits his days at high school into two halves – half working online from home and half at school. This combination of online classes from home and attending half day in-person allows him to minimize fatigue while maximizing opportunities for the best learning and for seeing friends at school.
Despite managing daily health problems related to his muscle weakness, he has a very full and satisfying life. He recently got his driver’s license. Adam loves games, swimming, reading and science and he plans to major in Computer Science in college.
You can read more about Titin-related centronuclear myopathies below.
- Congenital titinopathy: Comprehensive characterisation and pathogenic insights (Oates et al 2018)
- Genetic mystery solved
- Titin mutations cause centronuclear myopathy
- 219th ENMC workshop: Titinopathies – International database of TTN mutations and phenotypes
- Email: firstname.lastname@example.org
- Titin Related Muscle and Heart Disorders Discussion Group (closed)
- Titin Related Muscle and Heart Disorders Discussion Group (public)