All that waddles is not dystrophy
In the era of genetics, in patients with muscle disorders, genetic analysis has been replaced as the first‐line tool of investigation. The authors emphasise the importance of history taking and clinical examination in a girl presenting with progressive limb‐girdle pattern of weakness whose clinical exome sequence was negative, and also highlight the warning signs to look for a novel imitator of muscular dystrophy.
A 12‐year‐old girl, first born of third‐degree consanguineous parentage, had presented with progressive difficulty in walking, climbing upstairs and getting up from squatting posture from 11 years of age. She was evaluated at a regional hospital, as a case of limb‐girdle muscular dystrophy with normal creatinine‐phoshokinase, nerve conduction, echocardiography and negative clinical exome sequencing. Hence, the child was referred to our institute for a muscle biopsy to characterise the disease process.
On reviewing the history, her illness started at 10 years and 6 months of age with pain localised to thighs and both knee joints, initially on unaccustomed exertion at the start of dance classes; later it used to be present even while walking on plain ground and was relieved while taking rest. Six months later, she went on to develop a limb‐girdle pattern of weakness. The child also used to get tired excessively on walking short distances. However, there was no diurnal or seasonal fluctuation, and ocular or facio‐bulbar weakness. Clinically, possibility of a metabolic myopathy (glycogen storage disorders, fatty acid oxidation defects, mitochondrial myopathy due to respiratory chain defects) or an endocrine myopathy was considered.