Novel mutation of IL1RAPL1 gene in a nonspecific X-linked mental retardation (MRX) family.
Mental retardation (MR) affects approximately 2% of the population. About 10% of all MR cases result from defects of X-linked genes. Mutations in most of more than 20 known genes causing nonspecific form of X-linked MR (MRX) are very rare and may account for less than 0.5-1% of MR. Linkage studies in extended pedigrees followed by mutational analysis of known MRX genes in the linked interval are often the only way to identify a genetic cause of the disorder. We performed linkage analysis in several MRX families, and in one family with four males with MR we mapped the disease to an interval encompassing Xp21.2-22.11 (with a maximum LOD score of 2.71). Subsequent mutation analysis of genes located in this interval allowed us to identify a partial deletion of the IL1RAPL1 gene. Different nonoverlapping deletions involving IL1RAPL1 have been reported previously, suggesting that this region could be deletion-prone. In this report, we present the results of the molecular analyses and clinical examinations of four affected family members with the deletion in IL1RAPL1. Our data further confirm the importance and usefulness of linkage studies for gene mapping in MRX families and demonstrate that IL1RAPL1 plays an important role in the etiology of MRX. With the development of new methods (aCGH, MLPA), further rearrangements in this gene (including deletions and duplications) might be discovered in the nearest future.
Nawara
Magdalena
M
Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland. mnawara@imid.med.pl
Klapecki
Jakub
J
Borg
Katarzyna
K
Jurek
Marta
M
Moreno
Sarah
S
Tryfon
Jolanta
J
Bal
Jerzy
J
Chelly
Jamel
J
Mazurczak
Tadeusz
T
D000293:Adolescent; D000328:Adult; D002675:Child, Preschool; D022202:Chromosomes, Artificial, Bacterial; D041321:Chromosomes, Human, X / Q000235:genetics; D002999:Clone Cells; D020732:Cytogenetic Analysis; D005190:Family; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D053577:Interleukin-1 Receptor Accessory Protein / Q000235:genetics*; D008279:Magnetic Resonance Imaging; D008297:Male; D038901:X-Linked Intellectual Disability / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009483:Neuropsychological Tests; D010375:Pedigree
C407643:IL1RAPL1 protein, human; D053577:Interleukin-1 Receptor Accessory Protein