Final answer:
The neurological disorder not believed to be caused by defects in the calcium channel system among the given options is malignant hyperthermia (Option B), as it is more commonly associated with mutations in the ryanodine receptor (RYR1).
Step-by-step explanation:
The query concerns the relationship between calcium channel defects and various neurological disorders. Among the options listed, malignant hyperthermia (B) is not typically associated with defects in the calcium channel system. This condition is more commonly linked to mutations in the ryanodine receptor (RYR1), which is implicated in calcium release from the sarcoplasmic reticulum in muscle cells, rather than the calcium channels themselves. Lambert-Eaton myasthenic syndrome (A), hypokalemic periodic paralysis (C), familial hemiplegic migraine (D), and benign familial neonatal convulsions (E) are all disorders that have been linked to mutations in various calcium channels or related proteins, making option B the correct answer.