Bent spine syndrome: a phenotype of dysferlinopathy or a symptomatic DYSF gene mutation carrier.

tory. She had good muscle prowess in her childhood, but was not very active in sport before the onset of her complaints. Her symptoms started approximately 15 years ago with a slowly progressive gait disturbance. It had become difficult to climb stairs and to stay upright. Later in the course, she also noted mild muscle weakness in her shoulder girdle. The physical neurological investigation revealed severe thoracic kyphosis in the standing position, without physical signs of spondylosis or muscle spasticity ( fig. 1 a). A moderate paresis was also found in the abductor muscle of the shoulder girdle. Tendon reflexes were weak but symmetric. No limb ataxia, trunk ataxia or sensory loss was present. The physical symptoms were characteristic for bent spine syndrome. Routine laboratory parameters like liver and muscle enzyme levels, including serum CK level, were within normal range. Electromyography (EMG) of the vastus lateralis and tibialis anterior muscles did not show any signs of denervation. The interference pattern was normal, and a mixture of both highand low-amplitude muscle action potentials was found, with an increase of polyphasic muscle action potentials. EMG of the paraspinal, infraspinatus and deltoid muscles, however, showed a typical myopathic pattern with Dear Sir, A bent spine can result from paraspinal muscle weakness of different causes. The symptom has also been described as bent spine syndrome or camptocormia [1, 2] . More or less incomplete fatty degeneration of the erector spine muscles has been found in these cases [3, 4] . While camptocormia is an ageand disorder-related symptom, the primary degeneration of the erector spinae muscles is regarded as a muscle disorder, and denominated as bent spine syndrome. Different etiology could result in paraspinal muscle weakness, such as inflammatory myopathies [5, 6] , metabolic disorders [7, 8] and, rarely, genetically determined degenerative muscle disorders such as ryanodine receptor gene (RYR1) mutation [9] , D4Z4 gene mutations (which characterize facioscapulohumeral dystrophy [4, 10] ) and, as described in one case, a DYSF gene mutation [3] . We present the history of a 67-year-old woman with bent spine syndrome, in whom the mutation of the DYSF gene also was the probable background of bent spine syndrome.