Familial dysautonomia: A diagnostic dilemma. Chronic lung disease with signs of an autoimmune disease

We present an 11-year-old girl with sensory and autonomic neurological dysf unction, and respiratory insufficiency caused by recurrent aspiration. The diagnosis of familial dysautonomia (FD) was confirmed by a missing axonal f lare to histamine, miosis in response to conjunctival methacholine and homo zygous polymorphic linked markers DS58(18) and DS159(7) on chromosome 9. As hkenazi Jewish descent could not be ascertained by history. A variety of po sitive tests for autoantibodies were initially interpreted as evidence for systemic lupus erythematosus vs. overlap syndrome with pulmonary, cerebral, skin, and ocular involvement. The diagnosis of FD was delayed because of t he rarity of this disorder in Germany (second case reported). We discuss po ssible explanations for the misleading immunological findings, including in terference by antibodies binding to milk proteins used as blocking reagents in enzyme-linked immunoassays and circulating immune-complexes due to chro nic aspiration pneumonitis. (C) 2001 Wiley-Liss, Inc.