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Eccles et al note that joint hypermobility is commonly associated
with psychiatric, anxiety and psychosomatic presentations.(1)
For at least one psychiatric disorder with joint hypermobilty, there
is a known genetic cause. Both joint hypermobility and anxiety are
clinical features of Fragile X syndrome which is a result of expansions of
CGG repeats at the 5' untranslated region of the FMR1 gene which is
located at q27.3 on the X chromosome. The expansion silences transcription
of the protein FMRP, a protein which normally regulates protein synthesis
at neuronal dendrites. This loss of regulation is an explanation for the
finding of abnormally long and immature dendritic spines in the brains of
people with Fragile X syndrome and of the consequent phenotypic
presentations of impaired learning and memory (2), and as prompted by
Eccles et al, by anxiety.
It may transpire that Fragile X syndrome is the prototype joint
hypermobilty brain- body interaction disorder, and joint hypermobilty may
also be a sub-phenotype of Fragile X syndrome.
1. Eccles J, Harrison N, Critchley H. Joint hypermobilty: psychiatric
manifestations. BMJ 2011: 398-399.
2. Garber K, Visootsak J, Warren T. Fragile X syndrome. European
Journal of Human Genetics 2008; 16: 666-672.
Competing interests:
No competing interests
26 February 2011
David Ingle
CT3 in Psychiatry.
Ryburn Centre, Fieldhead Hospital, Ouchthorpe Lane, Wakefield WF1 3SP.
Joint hypermobility, anxiety and Fragile X syndrome
Eccles et al note that joint hypermobility is commonly associated
with psychiatric, anxiety and psychosomatic presentations.(1)
For at least one psychiatric disorder with joint hypermobilty, there
is a known genetic cause. Both joint hypermobility and anxiety are
clinical features of Fragile X syndrome which is a result of expansions of
CGG repeats at the 5' untranslated region of the FMR1 gene which is
located at q27.3 on the X chromosome. The expansion silences transcription
of the protein FMRP, a protein which normally regulates protein synthesis
at neuronal dendrites. This loss of regulation is an explanation for the
finding of abnormally long and immature dendritic spines in the brains of
people with Fragile X syndrome and of the consequent phenotypic
presentations of impaired learning and memory (2), and as prompted by
Eccles et al, by anxiety.
It may transpire that Fragile X syndrome is the prototype joint
hypermobilty brain- body interaction disorder, and joint hypermobilty may
also be a sub-phenotype of Fragile X syndrome.
1. Eccles J, Harrison N, Critchley H. Joint hypermobilty: psychiatric
manifestations. BMJ 2011: 398-399.
2. Garber K, Visootsak J, Warren T. Fragile X syndrome. European
Journal of Human Genetics 2008; 16: 666-672.
Competing interests: No competing interests