Leucine-rich repeat transmembrane neuronal protein 1 (LRRTM1) is a protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that in humans is encoded by the LRRTM1 gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

.

LRRTM1 is the first gene linked to increased odds of being left-handed

Left-handed

Left-handedness is the preference for the left hand over the right for everyday activities such as writing. In ancient times it was seen as a sign of the devil, and was abhorred in many cultures...

, at least if inherited from the father's side. Possessing one particular variant of the LRRTM1 gene slightly raises the risk of psychotic mental illness

Mental illness

A mental disorder or mental illness is a psychological or behavioral pattern generally associated with subjective distress or disability that occurs in an individual, and which is not a part of normal development or culture. Such a disorder may consist of a combination of affective, behavioural,...

es such as schizophrenia

Schizophrenia

Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...

, again only if inherited from the father's side.

As the name implies, its protein product is a transmembrane protein

Transmembrane protein

A transmembrane protein is a protein that goes from one side of a membrane through to the other side of the membrane. Many TPs function as gateways or "loading docks" to deny or permit the transport of specific substances across the biological membrane, to get into the cell, or out of the cell as...

 that contains many leucine rich repeats and is present in neuron

Neuron

A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...

s. It is expressed during the development of specific forebrain structures and shows a variable pattern of maternal downregulation (genomic imprinting).