MRX42: two linkage intervals, one in the pericentromeric region and one in Xq26, and the impact for carrier risk estimation.
A nonspecific X-linked mental retardation (MRX) family is reported with four mild to moderately affected males and no intellectual impairment in their obligate carrier mothers. Linkage analysis obtained the same multipoint lod score of 2.08 for two intervals on the X chromosome already reported to be linked to other MRX and syndromic X-linked mental retardation (XLMR) families: one pericentromeric and the other at Xq26. Since the responsible gene is not yet characterized, haplotyping is presently the only means available for carrier and prenatal testing for this form of MRX. Carrier risk estimation using pedigree and haplotype data for five females at risk is presented, and the difficulties of prenatal diagnosis given linkage to two different regions is discussed.
Golla
Astrid
A
Department of Medical Genetics, University of Munich, Munich, Germany.
Rost
Imma
I
Jedele
Kerry Baldwin
KB
Albert
Angelika
A
Murken
Jan
J
Holinski-Feder
Elke
E
D000328:Adult; D018797:Cell Cycle Proteins / Q000235:genetics; D002503:Centromere; D002874:Chromosome Mapping; D020732:Cytogenetic Analysis; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1; D005817:Genetic Counseling; D008040:Genetic Linkage; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics; D010375:Pedigree; D016601:RNA-Binding Proteins; D064067:Rho Guanine Nucleotide Exchange Factors; D012307:Risk Factors; D014960:X Chromosome
D018797:Cell Cycle Proteins; D051860:Fragile X Messenger Ribonucleoprotein 1; D020662:Guanine Nucleotide Exchange Factors; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; D064067:Rho Guanine Nucleotide Exchange Factors; C497683:FMR1 protein, human