Myotonic Dystrophy Type 2 (DMII) is a multisystemic disorder, with average age of onset after the age of 45 years presenting with proximal limb weakness, cataracts and endocrine abnormalities. The first symptom is most commonly leg weakness, followed by myalgia and myotonia. On examination, neck flexors and proximal limb girdle muscle are preferentially affected. Axial weakness typically follows limb involvement.

42-year-old female with 3 years progressive difficulty maintaining upright posture, with past medical history of bilateral cataracts and thoracolumbar scoliosis. No family history of neuromuscular conditions. Physical examination showed full proximal and distal strength, no atrophy, normal tone, preserved reflexes, and no percussion or grip myotonia. She had an abnormal posture with almost 90 degree flexion of thoracolumbar spine that abated in the recumbent position. Mild elevation in CK and aldolase, negative paraneoplastic panel. MRIs of the spine showed prominent thoracolumbar levoscoliosis, and disc bulges at L4-L5 and L5-S1. EMG showed diffuse electrical myotonia, increased insertional, spontaneous activity, and myopathic motor unit action potentials in selected proximal muscles sartorius, iliopsoas, sternocleidomastoid and cervical paraspinals. Genetic testing showed >75 repeats CNBP gene, a variant of unknown significance in CACNA1S (c.2048 G>A), and normal DMPK. Testing for Pompeii disease was negative.

This is a case of a 42-year-old female presenting with 3 years camptocormia, bilateral cataracts and history of levoscoliosis. Genetic testing with pathogenic number of repeats in CNBP, and EMG with diffuse myotonia and myopathic MUAPs, are consistent with a diagnosis of DMII. The most common causes of camptocormia are idiopathic axial myopathy, Parkinson’s disease, and degenerative spine disease. Myopathies associated with camptocormia often present with more generalized muscle weakness. DMII rarely presents with camptocormia, and when present, axial weakness typically follows limb weakness. This case highlights the necessity of diagnostic vigilance to ensure timely diagnosis and management.