Influence of serotonin receptor 2A His452Tyr polymorphism on brain temporal structures: a volumetric MR study

• DOI: 10.1038/sj.ejhg.5201573
• Publication Date: 2006-01-25T07:09:53Z
• Authors: Nicola Filippini; Catia Scassellati; Marina Boccardi; Michela Pievani; Cristina Testa; Luisella Bocchio-...; Giovanni B Frisoni; Massimo Gennarelli
• Keywords: Adult; Male; 0301 basic medicine; Genotype; Parahippocampal Gyrus/anatomy & histology/physiology; Hippocampus/anatomy & histology/physiology; Hippocampus; Memory/physiology; 03 medical and health sciences; Gene Frequency; Memory; Humans; Temporal Lobe/anatomy & histology/physiology; Histidine; Receptor, Serotonin, 5-HT2A; Amino Acid Substitution/genetics; Tyrosine/genetics; Neurons; Neuronal Plasticity; Polymorphism, Genetic; Genetic Carrier Screening; Neuronal Plasticity/genetics; Middle Aged; Magnetic Resonance Imaging; Temporal Lobe; Histidine/genetics; Amino Acid Substitution; Parahippocampal Gyrus; Tyrosine; Female; Neurons/physiology; Receptor, Serotonin, 5-HT2A/genetics

Serotonin (5-HT) receptors 2A are expressed in brain regions involved in memory and learning processes. Recently, a functional single nucleotide polymorphism in the 5-HT2A receptor gene leading to an amino-acid substitution at residue 452 (His452Tyr) has been involved in memory performance, persons with the rare 452Tyr allele showing poorer memory performance compared to His452His subjects. To investigate a putative structural effect of this polymorphism on temporal areas typically involved in memory processes, we performed voxel-based morphometry (VBM) and region-of-interest (ROI) volumetric analysis on high-resolution magnetic resonance images in 15 carriers and 61 noncarriers of the 452Tyr allele. ROI volumetric analysis showed a significant reduction of the fractional volume of the temporal white matter in 452Tyr carriers (0.67+/-0.07 vs 0.73+/-0.08; P=0.007). VBM confirmed this finding and in addition showed reduced grey matter in the left hippocampus, left inferior temporal gyrus, and bilaterally in the middle and superior temporal gyrus. A possible effect on synaptic plasticity or neurodevelopment might explain the influence of the His452Tyr polymorphism on temporal brain structures, and this might be the basis for poorer memory performance in 452Tyr carriers. These findings should be considered preliminary and future replication is needed.