Mb. Denckla et al., RELATIONSHIP BETWEEN T2-WEIGHTED HYPERINTENSITIES (UNIDENTIFIED BRIGHT OBJECTS) AND LOWER IQS IN CHILDREN WITH NEUROFIBROMATOSIS-1, American journal of medical genetics, 67(1), 1996, pp. 98-102
To address the controversy regarding the relationship between cognitiv
e impairment (lowering of IQ) and magnetic resonance imaging (MRI) cha
racteristics (T2-weighted hyperintensities or unidentified bright obje
cts [UBOs]) in children with neurofibromatosis-1 (NP-1), we used a pai
rwise NF-1/sibling design; we set out to predict the lowering of IQ in
each child with NF-1 as a discrepancy from the IQ of an unaffected si
bling (D-SIQ). Our multiple regression model included the age of the c
hild with NF-1, familial or sporadic nature of the NF-1, number of loc
ations in the child's brain occupied by T2-weighted hyperintensities (
UBOs), and the volumetric percentage of brain tissue occupied by T2-we
ighted hyperintensities (UBOs). Only the number of locations occupied
by UBOs accounted for IQ lowering (D-SIQ) in children with NF-1 (42% o
f the variance in D-SIQ). This is the first report to confirm that a c
ontinuum of lowered IQs in NF-l-affected children exists in relation t
o the distribution of UBOs (range 0-7), not just presence (vs. absence
) of any UBOs. (C) 1996 Wiley-Liss, Inc.