MedGen

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome) is an adult-onset inflammatory disease that primarily affects males and is caused by somatic, not germline, mutations. The disorder is characterized by adult onset of rheumatologic symptoms at a mean age of 64 years. Features include recurrent fevers, pulmonary and dermatologic inflammatory manifestations, vasculitis, deep vein thrombosis, arthralgias, and ear and nose chondritis. Laboratory studies indicate hematologic abnormalities, including macrocytic anemia, as well as increased levels of acute-phase reactants; about half of patients have positive autoantibodies. Bone marrow biopsy shows degenerative vacuolization restricted to myeloid and erythroid precursor cells, as well as variable hematopoietic dyspoiesis and dysplasias. The condition does not respond to rheumatologic medications and the features may result in premature death (summary by Beck et al., 2020). [from OMIM]

X-linked infantile spinal muscular atrophy (XL-SMA) is characterized by congenital hypotonia, areflexia, and evidence of degeneration and loss of anterior horn cells (i.e., lower motor neurons) in the spinal cord and brain stem. Often congenital contractures and/or fractures are present. Intellect is normal. Life span is significantly shortened because of progressive ventilatory insufficiency resulting from chest muscle involvement. [from GeneReviews]