Which disorder involves antibodies against Purkinje cell antigens and is linked to small cell lung cancer?

The disorder that involves antibodies against Purkinje cell antigens and is associated with small cell lung cancer is paraneoplastic cerebellar degeneration. This condition is a form of neurological dysfunction that occurs as a result of a cancerous tumor elsewhere in the body—in this case, small cell lung cancer. The immune response triggered by the tumor can lead to the production of antibodies that mistakenly target and attack the neurons in the cerebellum, specifically the Purkinje cells.

Patients with paraneoplastic cerebellar degeneration usually present with symptoms that include ataxia (lack of voluntary coordination of muscle movements), dysarthria (difficulty speaking), and impaired balance, primarily due to the degeneration of the cerebellum. The connection between small cell lung cancer and this neurological syndrome highlights the concept of paraneoplastic syndromes, where cancer can induce a remote syndrome through immune-mediated mechanisms.

The other options do not involve antibodies against Purkinje cell antigens or have the same association with small cell lung cancer. For instance, myasthenia gravis involves antibodies against acetylcholine receptors at the neuromuscular junction, and Lambert-Eaton myasthenic syndrome is linked to antibodies targeting presynaptic calcium channels, neither of which are associated