Disruptions of the novel KIAA1202 gene are associated with X-linked mental retardation.
The extensive heterogeneity underlying the genetic component of mental retardation (MR) is the main cause for our limited understanding of the aetiology of this highly prevalent condition. Hence we set out to identify genes involved in MR. We investigated the breakpoints of two balanced X;autosome translocations in two unrelated female patients with mild/moderate MR and found that the Xp11.2 breakpoints disrupt the novel human KIAA1202 (hKIAA1202) gene in both cases. We also identified a missense exchange in this gene, segregating with the Stocco dos Santos XLMR syndrome in a large four-generation pedigree but absent in >1,000 control X-chromosomes. Among other phenotypic characteristics, the affected males in this family present with severe MR, delayed or no speech, seizures and hyperactivity. Molecular studies of hKIAA1202 determined its genomic organisation, its expression throughout the brain and the regulation of expression of its mouse homologue during development. Transient expression of the wild-type KIAA1202 protein in HeLa cells showed partial colocalisation with the F-actin based cytoskeleton. On the basis of its domain structure, we argue that hKIAA1202 is a new member of the APX/Shroom protein family. Members of this family contain a PDZ and two ASD domains of unknown function and have been shown to localise at the cytoskeleton, and play a role in neurulation, cellular architecture, actin remodelling and ion channel function. Our results suggest that hKIAA1202 may be important in cognitive function and/or development.
Hagens
Olivier
O
Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Ihnestrasse 73, 14195, Berlin, Germany.
Dubos
Aline
A
Abidi
Fatima
F
Barbi
Gotthold
G
Van Zutven
Laura
L
Hoeltzenbein
Maria
M
Tommerup
Niels
N
Moraine
Claude
C
Fryns
Jean-Pierre
JP
Chelly
Jamel
J
van Bokhoven
Hans
H
Gécz
Jozef
J
Dollfus
Hélène
H
Ropers
Hans-Hilger
HH
Schwartz
Charles E
CE
de Cassia Stocco Dos Santos
Rita
R
Kalscheuer
Vera
V
Hanauer
André
A
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D041321:Chromosomes, Human, X; D003001:Cloning, Molecular; D004247:DNA; D006801:Humans; D038901:X-Linked Intellectual Disability / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013347:Subcellular Fractions / Q000378:metabolism; D014178:Translocation, Genetic
D004247:DNA