Triple A (Allgrove) syndrome due to AAAS gene mutation with a rare association of amyotrophy

Introduction Triple A (Allgrove) syndrome is a rare autosomal recessive disorder characterized by cardinal features of primary adrenal insufficiency (AI) due to adrenocorticotropic hormone (ACTH) resistance, achalasia, and alacrima. It is frequently associated with neurological manifestations such as autonomic dysfunction, cognitive dysfunction, cranial nerve, or motor involvement. Amyotrophy/motor neuron disease is a rare association. Case presentation We herein report a 19-year-old boy diagnosed with triple A syndrome (TAS), with the classic triad of ACTH-resistant adrenal insufficiency, achalasia, and alacrima. Additionally, he had distal spinal muscle amyotrophy. Alacrima was the earliest feature evident in early childhood, followed by achalasia at 12 years of age. He was diagnosed with AI at the age of 19 years, with involvement of the mineralocorticoid axis. Further evaluation showed a neurogenic pattern on electromyography, consistent with a diagnosis of motor neuron disease. A nerve conduction study revealed no significant neuropathy. Genetic analysis confirmed a pathogenic homozygous mutation in the AAAS gene c.43C>A, p.Gln15Lys. He improved with glucocorticoid and mineralocorticoid supplements for AI, and nifedipine for achalasia and artificial tears. He is planned for esophagomyotomy. Conclusion In any young patient with AI not due to congenital adrenal hyperplasia, Allgrove syndrome should be ruled out. Though mineralocorticoid sparing pattern is classical, it can rarely be involved, as seen in the index case. Various components of the syndrome, as well as amyotrophy and other neurologic features, may present in a metachronous fashion. Hence, a high index of clinical suspicion can aid in early diagnosis and management.