Abstract
Subcortical band heterotopia (SBH) are bilateral and symmetric ribbons of gray matter found in the central white matter between the cortex and the ventricular surface, which comprises the less severe end of the lissencephaly (agyria-pachygyria-band) spectrum of malformations. Mutations in DCX (also known as XLIS) have previously been described in females with SBH. We have now identified mutations in either the DCX or LIS1 gene in three of 11 boys studied, demonstrating for the first time that mutations of either DCX or LIS1 can cause SBH or mixed pachygyria-SBH (PCH-SBH) in males. All three changes detected are missense mutations, predicted to be of germline origin. They include a missense mutation in exon 4 of DCX in a boy with PCH-SBH (R78H), a different missense mutation in exon 4 of DCX in a boy with mild SBH and in his mildly affected mother (R89G) and a missense mutation in exon 6 of LIS1 in a boy with SBH (S169P). The missense mutations probably account for the less severe brain malformations, although other patients with missense mutations in the same exons have had diffuse lissencephaly. Therefore, it appears likely that the effect of the specific amino acid change on the protein determines the severity of the phenotype, with some mutations enabling residual protein function and allowing normal migration in a larger proportion of neurons. However, we expect that somatic mosaic mutations of both LIS1 and DCX will also prove to be an important mechanism in causing SBH in males.
Original language | English (US) |
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Pages (from-to) | 1757-1760 |
Number of pages | 4 |
Journal | Human molecular genetics |
Volume | 8 |
Issue number | 9 |
DOIs | |
State | Published - 1999 |
Externally published | Yes |
Bibliographical note
Funding Information:We would like to thank the families who participated in this study for their help and enthusiasm and A.J. Barkovich for referral of patient LP94-051. We are grateful to Stephanie Mewborn, Laura Dudlicek and Judy Fantes for technical support and to Patti L. Mills for clinical coordination. This work was supported by NIH grants R01-NS35515 (to M. Elizabeth Ross and W.B.D.) and P01-NS39404 (to W.B.D. and D.H.L.).