Generalized amyloid in a family of Swedish origin. A study of 426 family members in seven generations of a new kinship with neuropathy, nephropathy, and central nervous system involvement.

We report a new kinship with systemic amyloid presenting as peripheral neuropathy in the fourth and fifth decades of life. A progressive sensory and motor loss starting in the lower extremities occurs from this disease, and there is subsequent renal, cardiac, gastrointestinal, ocular, and cutaneous involvement. Histologic studies show that amyloid deposition is mainly in connective tissue structures; there is an unusual infiltration of the meninges and central nervous system. Review of records of 426 family members in seven generations showed that this disease is inherited as an autosomal dominant. The absence of immunoglobulin disorders in two affected family members studied in depth suggests that this is not the primary type of amyloid in which the deposits are composed of fragments of immunoglobulin light chains. Similarly the absence of elevated levels of protein SAA (the serum precursor of secondary amyloid) suggests that this is not a secondary form of amyloid.