A Case Study : Further Diagnosis of Central Core Disease by Next Generation Sequencing
Introduction: Central core disease (CCD), also known as central core myopathy, is an autosomal dominantly inherited muscle disorder present from birth that negatively affects the skeletal muscles. It is usually diagnosed by conventional evaluations. But some types of CCD could not.
Case report: A 13-year-old male first visited our rehabilitation clinic for his waddling gait. He also showed Achilles tendon tightness and had difficulty running at school. On his laboratory exam, Muscle enzyme CK/LDH were elevated to 897/452.
At first, he had gait disturbance since he started walking as a toddler. At age of 9, he had several episodes of slip down while walking. His parents took him to the Orthopedic surgery department of Seoul National University Hospital. A neurology doctor of SNUH suspected Duchenne’s muscle dystrophy. And then the nerve conduction study and needle electromyographic study showed a myopathy involving upper and lower extremities. And muscle biopsy was also done. But there was no pathognomonic finding for a myopathy.
At age of 18, He visited our clinic again, he still showed Gower’s sign and Achilles tendon tightness, but both Pevus cavus, proximal muscle atrophy was not found. He newly showed both hand tremor.
We decided to perform Next generation sequencing(NGS) to diagnosis a myopathy or an ataxia. In report of NGS, RVR1 gene mutation(c.4339G>A), 2 TTN gene mutations (c. 25811G>A, c.53585G>A) were found.
The RYR1 gene provides instructions for making a protein called ryanodine receptor 1. A RYR1 mutation leads to muscle weakness patterns of Central Core disease.
Conclusion: Conventional diagnostic evaluations such as NCS, EMG, Muscle biopsy are not enough and have limitations to diagnose Central core disease. Even though there still lies limitation of application due to its cost, next generation sequencing should be considered to narrow down diagnosis. |
