Ataxia-telangiectasia (AT) is a rare, autosomal recessive disorder in which the diagnosis is obvious when ataxia and telangiectasia are both present. However, the diagnosis can be made upon the onset of ataxia and before the appearance of telangiectasia if it is considered and confirmed by laboratory tests. Early diagnosis is important for genetic counseling, appropriate care, and the avoidance of unnecessary tests. The purpose of the present study was to identify factors responsible for delays in diagnosis of AT. The records of all patients seen at the AT Clinical Center from July 1, 1995 to September 1, 1996 were reviewed. Patients were defined as having AT if they had characteristic neurologic dysfunction or family history and one of the following criteria (1) oculocutaneous telangiectasia (2) elevated serum alpha feto-protein or (3) x-ray induced chromosomal breakage. From a total of 42 patients referred to the AT Clinic, 36 patients were index cases of AT in their respective families. The median age of diagnosis (70 mos) occurred after the onset of gait abnormalities (15 mos) and followed closely the development of telangiectasia (68.5 mos). In over two-thirds of cases, the diagnosis was not made until telangiectasia appeared (25/36 index cases). The most common misdiagnosis before AT was established was cerebral palsy (23/36 index cases). A complete referral history was available in 31 out of the 36 index cases. 24 of these 31 patients were seen by at least one pediatric neurologist for their gait abnormalities before the onset of telangiectasia; of these, only 8 patients had the diagnosis of AT made before the onset of telangiectasia. 15 siblings (4 with AT) were born after the onset of ataxia but before the establishment of a diagnosis in the propositi. Our experience suggests that the name, while a concise and memorable label for the disorder, is also a barrier to early diagnosis. We recommend the use of serum alpha feto-protein as a diagnostic test for young children presenting with ataxia alone.
