Fibrillary Protein Deposits With Tubular Substructure in a Systemic Disease Beginning as Cutis Laxa

We read with interest the article by Niemi et al¹ describing a previously unknown dermatologic disease caused by proteinaceous Congo red—negative amyloidlike deposits and clinically appearing as cutis laxa.

While this may be a new disorder in dermatologic practice, it is well known to the nephrology and renal pathology communities. Beginning in 1977 with the report of Rosenmann and Eliakim² of a Congo red— negative amyloidlike substance in glomeruli from a patient with nephrotic syndrome, many additional studies have documented these fibrillary infiltrates in glomeruli. While the fibrils are of the same size in a given patient, there is considerable patient-to-patient variation, with fibrils ranging from 10 to 48 nm in diameter. Although some controversy exists regarding terminology, many investigators term the disorder with thin fibrils (10 to 20 nm) fibrillary glomerulonephritis and with thicker and hollow fibrils immunotactoid glomerulopathy.³ The fibrils are likely immune proteins. In