Camptocormia in a young man with anti-GAD-seropositive stiff-person syndrome

Stiff-person syndrome (SPS) usually manifests as an autoimmune neuromuscular disorder characterised by pronounced and advancing rigidity, primarily affecting the trunk and proximal muscles. There are various clinical subtypes like classic SPS (truncal stiffness, generalised rigidity and muscle spasms), partial SPS (stiff-limb syndrome) and uncommon forms including progressive encephalomyelitis with rigidity and myoclonus. Camptocormia, defined as forward flexion of the spine in the upright position that disappears in the supine position, without fixed deformity, has been described only in two cases as an initial presentation of Anti glutamic acid decarboxylase (GAD) autoimmunity. We encountered a young male presenting with a progressive forward-leaning posture and involuntary rhythmic movements in the lower limb. Diagnostic workup included MRI, blood routines, autoimmune screening, genetic testing, lumbar puncture and electromyography. Elevated serum anti-GAD antibody levels, inflammatory CSF and certain other clinical features supported the diagnosis of SPS. Treatment involved benzodiazepines, muscle relaxants and immunotherapy with intravenous immunoglobulin. This case underscores the importance of considering immune-mediated causes, such as SPS, in patients presenting with camptocormia.