Non-syndromic X-linked mental retardation: from a molecular to a clinical point of view.
This review focuses on the 19 identified genes involved in X-linked "non-syndromic" mental retardation (MR) and defines the signaling pathways in which they are involved, focusing on emerging common mechanisms. The majority of proteins are involved in three distinct pathways: (1) Rho GTPases pathway modulating neuronal differentiation and synaptic plasticity; (2) Rab GTPases pathway regulating synaptic vesicle cycling; (3) gene expression regulation. The function of four proteins (ACSL4, AT2, SLC6A8, and SAP102) could not be reconciled to a common pathway. From a clinical point of view, the review discusses whether some common dysmorphic features can be identified even in non-syndromic MR patients and whether it is correct to maintain the distinction between "non-syndromic" and "syndromic" MR.
Renieri
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Medical Genetics, Department of Molecular Biology, University of Siena, Siena, Italy. renieri@unisi.it
Pescucci
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C
Longo
I
I
Ariani
F
F
Mari
F
F
Meloni
I
I
D041321:Chromosomes, Human, X / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D038901:X-Linked Intellectual Disability / Q000235:genetics* / Q000473:pathology*; D009473:Neuronal Plasticity / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics