ELECTRORETINOGRAM IN DUCHENNE BECKER MUSCULAR-DYSTROPHY/

The authors studied all cases with dystrophinopathy consecutively revi ewed between May 1995 and December 1996 by meads of electroretinograph y (ERG), which was recorded using Skin eyelid electrodes and with stan dard flash stimulation. This methodology can detect the functional abn ormalities associated with dystrophinopathies. The most valuable param eter is the ratio of B-wave amplitude to A-wave amplitude (B/A amplitu de ratio), which was greater than 2 in all normal control Patients (n = 10) and nondystrophinopathic muscular dystrophy (MD) patients (n = 2 ). It was less than 2 in 100% (n = 16) of Duchenne muscular dystrophy (DMD) patients (mean ratio 0.73; range 0.4-1.26). It was less than 2 i n 71% (n = 7) of Becker muscular dystrophy (DMD) patients (mean ratio 1.12; range 0.88-1.37), add less than 2 in 50% (n = 4) of definitive D MD carriers. Twenty nine percent of BMD, 50% of DMD carriers, add the only case with asymptomatic dystrophinopathy had normal ratios (greate r than 2), The differences between the mead ratios of control, DMD, an d BMD groups were statistically significant, all of them with P < 0.00 1. ERG abnormalities of dystrophinopathies were associated with the mo re severe muscular phenotype but not with the presence or location of gene deletion. ERG is an easy and simple technique that is useful in c ases of suspected dystrophinopathy with a nonconclusive molecular stud y. It is less useful in patients who are DMD carriers. (C) 1998 by Els evier Science Inc. All rights reserved.