Clinical manifestations of NF1 in African-Americans and Caucasians

Abstract

Most of the clinical manifestations of NF1 are thought to occur in similar frequencies in different ethnic groups. One exception to this assumption may be optic glioma, which has been reported to be less common in African-Americans. We have compared the manifestations of NF1 in a retrospective analysis of 55 individuals with NF1, including 39 Caucasians and 16 African-Americans in the first part of the study. All patients met the NIH consensus criteria for NF1. The diagnosis of NF1 was established at the mean age of 11.1 years in African-Americans and 8.3 years in Caucasians (±SD 6.9 years for African-Americans and 12.3 years for Caucasians; p<0.01). The results revealed that most of the findings were seen in similar frequencies in African-Americans and Caucasians. However, the following manifestations were found to be different: 3 of 16 African-Americans and 3 of 39 Caucasians were noted to have plexiform neuroma. None of the African-Americans were found to develop renal artery stenosis, although it was noted in 2 Caucasians. Three patients from the African-American group were found to develop intracranial tumors other than optic glioma, although none of the Caucasians were noted to have similar tumors in our sample. One explanation for these differences would be that African-Americans might be getting medical attention only if they have significant problems such as plexiform neuroma or intracranial tumors. To better evaluate the previously reported difference on the frequency of optic glioma, we are collecting a larger sample currently including 84 African-Americans and 880 Caucasians. Thus far optic glioma has been diagnosed in 4 of the 84 (4.8%) patients whose both parents were African-Americans and in 144 of the 880 (16.4%) Caucasians (further analysis is continuing). Our results thus far suggest that the manifestations of NF-1 are somewhat different in African-Americans, a lower frequency of optic glioma being the most significant difference. Better understanding of clinical differences in patients with NF-1 from different ethnic groups will help to identify modifying genetic factors and to establish appropriate individualized diagnostic and management plans.