Tetraparesis and sensorimotor axonal polyneuropathy due to co-occurrence of Pompe disease and hereditary ATTR amyloidosis.

Hereditary transthyretin amyloidosis with polyneuropathy (hATTRPN) is an autosomal dominant multi-organ disorder manifesting in the third to fifth decade with the key clinical features of distal and painful sensory loss of the lower limbs and autonomic dysregulation. Motor neuropathy and cardiomyopathy evolve in the course of the disease. Pompe disease is an autosomal recessive disease leading to decreased levels of lysosomal enzyme acid α-glucosidase and proximal muscle weakness. We report the clinical features and diagnostic workup in the rare case of a patient with ATTR amyloidosis and late-onset Pompe disease, both genetically confirmed. We performed a detailed clinical assessment, exome sequencing, and biochemical measurements. The patient presented with a distal, painful hypaesthesia of both legs, a cardiomyopathy, and a muscle weakness in the form of a girdle-type pattern of the arms and legs at the beginning and a spreading to distal muscle groups in the course of disease. This study highlights the importance of searching for co-occurrence of rare monogenetic neuromuscular diseases, especially in cases in which all clinical features can be readily explained by a single gene defect.