RGD Reference Report - Non-specific X-linked semidominant mental retardation by mutations in a Rab GDP-dissociation inhibitor. - Rat Genome Database

Send us a Message



Submit Data |  Help |  Video Tutorials |  News |  Publications |  Download |  REST API |  Citing RGD |  Contact   

Non-specific X-linked semidominant mental retardation by mutations in a Rab GDP-dissociation inhibitor.

Authors: Bienvenu, T  des Portes, V  Saint Martin, A  McDonell, N  Billuart, P  CarriĆ©, A  Vinet, M C  Couvert, P  Toniolo, D  Ropers, H H  Moraine, C  van Bokhoven, H  Fryns, J P  Kahn, A  Beldjord, C  Chelly, J 
Citation: Bienvenu T, etal., Hum Mol Genet. 1998 Aug;7(8):1311-5.
RGD ID: 13208831
Pubmed: PMID:9668174   (View Abstract at PubMed)

Non-specific X-linked mental retardation (MRX) is a very common disorder which affects approximately 1 in 600 males. Despite this high frequency, little is known about the molecular defects underlying this disorder, mainly because of the clinical and genetic heterogeneity which is evident from linkage studies. Recently, a collaborative study using the candidate gene approach demonstrated the presence of mutations in GDIalpha, a Rab GDP-dissociation inhibitor encoded by a gene localized in Xq28, associated with non-specific mental retardation. GDIalpha is mainly a brain-specific protein that plays a critical role in the recycling of Rab GTPases involved in membrane vesicular transport. The study presented here was designed to assess the prevalence of mutations in the GDIalpha in mentally retarded patients and to discuss the clinical phenotypes observed in affected individuals. Mutation screening of the whole coding region of the GDIalpha gene, using a combination of denaturing gradient gel electrophoresis and direct sequencing, was carried out in 164 patients found negative for expansions across the FRAXA GCC repeat. In addition to the nonsense mutation recently reported in MRX48, we have identified a novel missense mutation in exon 11 of the GDIalpha gene in one familial form of non-specific mental retardation. In this family (family R), all affected males show moderate to severe mental retardation, and the X-linked semidominant inheritance is strongly suggested by the severe phenotypes in males with respect to mildly affected females or unaffected obligatory carriers. This study showed that the prevalence of GDIalpha mutations in non-specific mental retardation could be estimated to be 0.5-1%, and molecular diagnosis and genetic counselling in some cases of non-specific mental handicap can now be provided.

RGD Manual Disease Annotations    Click to see Annotation Detail View
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
non-syndromic X-linked intellectual disability  IAGP 13208831DNA:missense mutation:cds:p.R423P (human)RGD 
non-syndromic X-linked intellectual disability  ISOGDI1 (Homo sapiens)13208831; 13208831DNA:missense mutation:cds:p.R423P (human)RGD 

Objects Annotated

Genes (Rattus norvegicus)
Gdi1  (GDP dissociation inhibitor 1)

Genes (Mus musculus)
Gdi1  (GDP dissociation inhibitor 1)

Genes (Homo sapiens)
GDI1  (GDP dissociation inhibitor 1)


Additional Information