Non Coding CGG Repeat Expansion Diseases: An Update

Abstract

In recent years neurological disorders specifically neurodegenerative diseases have been recognised worldwide and has been diagnosed more and more by clinicians with the ever improving genetic techniques and is currently considered a leading cause of disability and death right from young to elderly age and might surpass the diagnosis of cancer in future as predicted by World Health Organization(WHO).This type of disorders are common in both high-and low-income countries and it is only predicted to increase as time goes by. Expanded trinucleotide repeats are GGGGGC, CAG, CGG, CCG, CTG, CUG, GAA, and GCN etc in the genome are considered to cause major neurodegenerative diseases in general population. Pathogenesis is different for different repeats however time of onset of the disease and severity will depend on trinucleotide repeat number. So, these type of disease comes under category of Trinucleotide repeat expansion disorders (TREDs). Here in this article we further update about the disease spectrum caused by CGG repeat expansion. Founder haplotypes and haploinsufficiency have been identified recently and its analysis in families may reveal a shared haplotype. Attention should be paid not only to familial cases but also to sporadic cases presenting with similar clinical features otherwise the diagnosis can be missed in early stages.