genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinians, Augustinian ...

, rs6313 also called T102C or C102T is a gene variation—a

single nucleotide polymorphism In genetics and bioinformatics, a single-nucleotide polymorphism (SNP ; plural SNPs ) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in ...

(SNP)—in the human ''

HTR2A The 5-HT2A receptor is a subtype of the 5-HT2 receptor, 5-HT2 receptor that belongs to the serotonin receptor family and functions as a GPCR, G protein-coupled receptor (GPCR). It is a cell surface receptor that activates multiple intracellular ...

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

that codes for the 5-HT_2A

receptor Receptor may refer to: * Sensory receptor, in physiology, any neurite structure that, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and respond ...

. The SNP is a

synonymous substitution A synonymous substitution (often called a ''silent'' substitution though they are not always silent) is the evolutionary substitution of one base for another in an exon of a gene coding for a protein, such that the produced amino acid sequence ...

located in exon 1 of the gene where it is involved in coding the 34th

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

serine Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α- amino group (which is in the protonated − form under biological conditions), a carboxyl group (which is in the deprotonated − ...

. As 5-HT_2A is a

neuroreceptor A neurotransmitter receptor (also known as a neuroreceptor) is a membrane receptor protein that is activated by a neurotransmitter. Chemicals on the outside of the cell, such as a neurotransmitter, can bump into the cell's membrane, in which the ...

the SNP has been investigated in connection with

brain function The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for special senses ...

s and

neuropsychiatric disorder A mental disorder, also referred to as a mental illness, a mental health condition, or a psychiatric disability, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. A mental disorder is ...

s, and it is perhaps the most investigated SNP for its gene. Two other SNPs in HTR2A have also received much attention:

rs6311 In genetics, rs6311 is a gene variation—a single nucleotide polymorphism (SNP)—in the human ''HTR2A'' gene that codes for the 5-HT2A, 5-HT2A receptor (biology), receptor. 5-HT2A is a neuroreceptor, and several scientific studies have investigat ...

and His452Tyr (rs6314). The T102C polymorphism has been shown to be in complete

linkage disequilibrium Linkage disequilibrium, often abbreviated to LD, is a term in population genetics referring to the association of genes, usually linked genes, in a population. It has become an important tool in medical genetics and other fields In defining LD, it ...

with the rs6311 (A-1438G). A less well investigated SNP of this gene is rs7997012.

Meta-analyses Meta-analysis is a method of synthesis of quantitative data from multiple independent studies addressing a common research question. An important part of this method involves computing a combined effect size across all of the studies. As such, th ...

seem to indicate that the SNP is directly associated with

schizophrenia Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...

, with

Alzheimer's disease Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...

, and two initial studies seem to indicate that it is not associated with

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor system, motor and non-motor systems. Symptoms typically develop gradually and non-motor issues become ...

. There have been multiple studies of the effect of this SNP on

clozapine Clozapine, sold under the brand name Clozaril among others, is a psychiatric medication and was the first atypical antipsychotic to be discovered. It is used primarily to treat people with schizophrenia and schizoaffective disorder who have ...

treatment response in

. A meta-analysis published in 1998 found an association.

Individual studies

Many individual studies have been done to investigate possible effects of the rs6313 polymorphism on

phenotypes In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological properti ...

such as

personality traits In psychology, trait theory (also called dispositional theory) is an approach to the study of human personality. Trait theorists are primarily interested in the measurement of ''traits'', which can be defined as habitual patterns of behavior, thou ...

or disorders and their

endophenotype In genetic epidemiology, endophenotype (or intermediate phenotype) is a term used to separate behavioral symptoms into more stable phenotypes with a clear genetic connection. By seeing the EP notion as a special case of a larger collection of mul ...

s. The C-

allele An allele is a variant of the sequence of nucleotides at a particular location, or Locus (genetics), locus, on a DNA molecule. Alleles can differ at a single position through Single-nucleotide polymorphism, single nucleotide polymorphisms (SNP), ...

has been associated with higher

extraversion Extraversion and introversion are a central trait dimension in human personality theory. The terms were introduced into psychology by Carl Jung, though both the popular understanding and current psychological usage are not the same as Jung's ...

personality scores among

borderline personality disorder Borderline personality disorder (BPD) is a personality disorder characterized by a pervasive, long-term pattern of significant interpersonal relationship instability, an acute fear of Abandonment (emotional), abandonment, and intense emotiona ...

patients and the presence of visual and auditory

hallucinations A hallucination is a perception in the absence of an external stimulus that has the compelling sense of reality. They are distinguishable from several related phenomena, such as dreaming ( REM sleep), which does not involve wakefulness; pse ...

in patients with late-onset Alzheimer's disease. Multiple studies have found that individuals with schizophrenia who are homozygous for the C-allele tend to do worse on working memory tasks than do individuals with a T-allele. Rs6313 has also been shown to be associated with

novelty seeking In psychology, novelty seeking (NS) is a personality trait associated with exploratory activity in response to novel stimulation, impulsive decision making, extravagance in approach to reward cues, quick loss of temper, and avoidance of frustrati ...

among Italian

mood disorder A mood disorder, also known as an affective disorder, is any of a group of conditions of mental and behavioral disorder where the main underlying characteristic is a disturbance in the person's mood. The classification is in the ''Diagnostic ...

patients and

reward dependence Reward dependence (RD) is characterized as a tendency to respond markedly to signals of reward, particularly to verbal signals of social approval, social support, and sentiment. When reward dependence levels deviate from normal we see the rise of ...

in a German population. The SNP may also be associated with

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects synovial joint, joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and h ...

. One study found no association between the SNP and suicidal behavior in a Chinese population, and another found no association with fibromyalgia syndrome.

References

SNPs on chromosome 13 {{genetics-stub