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. 2014 Jun 5:4:208.
doi: 10.7916/D8NG4NP3. eCollection 2014.

In the Gray Zone in the Fragile X Gene: What are the Key Unanswered Clinical and Biological Questions?

Deborah A Hall  1
Affiliations

In the Gray Zone in the Fragile X Gene: What are the Key Unanswered Clinical and Biological Questions?

Deborah A Hall. Tremor Other Hyperkinet Mov (N Y). .

Abstract

Smaller expansions (41-54 CGG repeats) in the fragile X mental retardation 1 (FMR1) gene are termed "gray zone" alleles. Only recently has interest in these expansions increased due to reporting of phenotypes unique to gray zone carriers or similar to those seen in individuals with larger expansions. As minimal research has focused on gray zone expansions, this paper asks several questions related to this topic. These include the following: What is the definition of the gray zone? Is there a risk of developing neurological signs in these carriers? Are there secondary gene effects that impact gray zone alleles or a biologic advantage to carrying these repeats? How do we counsel patients with gray zone expansions? The answers to these questions will help to determine the significance of these expansions and provide needed information to the research community and clinicians.

Keywords: Fragile X mental retardation 1 Gene; Fragile X-associated tremor/ataxia syndrome; Movement disorders.

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Conflict of interest statement

Conflict of Interests: The authors report no conflict of interest.

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