Table 2 Comparsion of gyral pattern (LIS grade and gradient) and associated brain abnormalities in lissencephalies related to TUBA1A gene, LIS1 gene, DCX gene and unexplained lissencephalies
DiagnosisNbLIS gradesLIS gradient, nCorpus callosumCerebellar vermian hypoplasiaDysgenesis of the internal capsule
1–234P>AA = PA>PPerisylvianMild hypoplasiaACC
ILS TUBA1A111 (9.1)0 (0)230 (0)0 (0)7 (63.6)8 (72.7)3 (27.3)8 (72.7)11 (100)
ILS17‡278 (29.6)14 (51.8)4 (14.8)27 (100)0 (0)0 (0)0 (0)14 (60.9)0 (0)0 (0)0 (0)
ILSX§337 (21.2)6 (18.2)12 (36.4)0 (0)3 (9.1)30 (90.9)0 (0)11 (35.5)0 (0)0 (0)0 (0)
ILS negative¶8413 (15.5)25 (29.8)52 (61.9)58 (69.1)15 (17.8)14 (16.7)3 (3.5)36 (42.8)2 (2.4)45 (53.6)3 (3.5)
  • Values are n (%).

  • ACC, agenesis of the corpus callosum (either partial or complete); ILS17, isolated lissencephaly sequence, chromosome 17 linked (either deletion or mutations); ILSX, isolated lissencephaly sequence, X-linked; LIS, lissencephaly (either sporadic or familial); LIS gradient, comparison of gyral pattern in anterior compared with posterior brain regions.

  • P>A, posterior more severe than anterior; A = P, anterior equal to posterior; A>P, anterior more severe than posterior.

  • In this comparison we included the 11 patients with TUBA1A mutations† (6 in this study and 5 originally described by Poirier et al and revisited here), 27 sporadic ILS17‡ (5 with deletion and 22 with point mutations), and 33 patients ILSX§ with 24 sporadic and 9 familial cases.

  • ILS negative¶ refers to patients for whom genetic analyses (LIS1, DCX, TUBA1A and ARX screenings) were negative. (For this comparison, we did not consider the 10 patients with subcortical band heterotopia (SBH) for whom no mutation was identified.