ABSTRACT
Circular RNA(circRNA)is an emerging class of endogenous non-coding RNA,which is widely expressed in the brain and plays an important role in a variety of biological processes.Research has shown that circRNA plays a key role in physiological and pathological processes of the brain,such as neurodevelopment,synaptic plasticity and neurodegenerative diseases through a variety of mecha-nisms such as adsorption of microRNA,binding to proteins and translation of peptides.In the field of drug addiction,the expression of circRNA is significantly changed in animal models and brains of addicts,and the regulation involves neural adaptation in brain regions that form the reward circuit such as the nucleus accumbens and prefrontal cortex.Additionally,addiction-related circRNAs are closely associated with neurotransmitter systems,signaling pathways,and neuroinflammatory responses,and they influ-ence the formation and maintenance of drug addiction by modulating gene expression networks related to drug addiction.Here,the biogenesis and regulatory mechanism of circRNA as well as its important role in brain function and drug addiction are reviewed in order to provide a new perspective for explora-tions of the pathological mechanism of drug addiction.
ABSTRACT
Objective:To report the clinical manifestation and genetic characteristics of a case of de novo Huntington′s disease due to paternal intermediate alleles. Methods:Clinical data and imaging features of a middle-aged female, who complained of unstable walking without positive family history and was admitted to Xuanwu Hospital, Capital Medical University on September 20, 2022, were retrospectively analyzed. The serum samples of the patient and her parents were used to screen HTT gene dynamic mutation in accordance with the principle of informed consent and voluntary. And the relevant literatures were reviewed. Results:This is a 38-year-old female with progressive course, who presented as ataxia, involuntary movement at the end of extremities, dystonia, and cognitive impairment. Imaging results showed atrophy of bilateral caudate nuclei, as well as decreased glucose metabolism of bilateral caudate nuclei, putamen and partial cortex. Genetic testing showed the abnormal expansion of polymorphic trinucleotide (CAG) repeats in HTT gene and confirmed the diagnosis of Huntington′s disease. The CAG repeat length of the patient was 17/47 (pathopoiesis), of the father was 17/35 (intermediate alleles), and of the mother was 17/17 (normal). Conclusions:Paternal intermediate alleles may cause the first case of Huntington′s disease in a family. Importantly, HTT gene screening should be performed for the patient and parents when the diagnosis of Huntington′s disease is clinically possible despite negative family history, to prevent the misdiagnosis.