Iris hamartomas in neurofibromatosis-1.

One hundred and forty three families with 261 subjects suffering from neurofibromatosis-1 (NF1) referred to our Center for genetic counselling. Ophthalmological evaluation was performed on a total of 326 subjects: 167 affected individuals and 159 unaffected relatives. Iris hamartomas were present in 108 out of 167 (65%) affected subjects: in 35 out of the 68 aged 0-9 years, in 29 out of the 47 aged 10- 19 years, and 44 out of the 52 aged over 19 years. This frequency, which was low if compared to previous studies, could partially be explained by a different age class distribution and sampling of NF1 patients. The negative pre-dictive value was 92% (95% confidence interval = 84- 100) for subjects under 20 years of age, and 94% (95% confidence interval = 89-99) for subjects aged 20 or more. The Authors concluded that iris hamartomas ought to be considered pathognomonic of NF1 and that complete ophthalmological evaluation of probands and of their first-degree relatives is required for correct genetic counselling.