FRMD7 mutations in Chinese families with X-linked congenital motor nystagmus.
OBJECTIVE
To identify mutations causing X-linked congenital motor nystagmus (XL-CMN) in Chinese families.


METHODS
Genomic DNA was prepared from peripheral blood leukocytes. Cycle sequencing was used to detect the sequence variation of the FERM domain containing 7 (FRMD7) gene, where mutations have been identified recently to associate with XL-CMN.


RESULTS
Sequencing of the coding and the adjacent intron regions of FRMD7 identified mutations in four families with XL-CMN, c.41-43delAGA (p.Lys14del) in exon 1, c.70G>A (p.Gly24Arg) in exon 2, c.436C>T (p.Arg146Trp) in exon 6, and c.685C>T (p.Arg229Cys) in exon 8, respectively, where the last two were novel. These mutations were not detected in 196 normal controls. In the two families with X-linked recessive CMN, females carrying a heterozygous mutation in FRMD7 did not have any sign of nystagmus.


CONCLUSIONS
Our results provide additional evidence for mutations in FRMD7 as a common cause of XL-CMN and expand its mutation spectrum. CMN in a Chinese family with pure X-linked recessive pattern, previously mapped to Xq23-q27, is associated with the c.41-43delAGA mutation in FRMD7.
Zhang
Qingjiong
Q
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China. qingjiongzhang@yahoo.com
Xiao
Xueshan
X
Li
Shiqiang
S
Guo
Xiangming
X
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000235:genetics*; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D002681:China; D003598:Cytoskeletal Proteins / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D040181:Genetic Diseases, X-Linked / Q000235:genetics*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D020417:Nystagmus, Congenital / Q000235:genetics*; D010375:Pedigree
D003598:Cytoskeletal Proteins; C516168:FRMD7 protein, human; D008565:Membrane Proteins