Table 1.

Definition of Various Terms Used in This Review

Term	Meaning
Allele	A given gene may have several variants across different individuals in a population; those variants are called the alleles of said gene.
Autosomal	Not linked to the X chromosome or the Y chromosome.
Centimorgan	A unit for measuring genetic linkage (how close regions on the same chromosome are).
Codon	A triplet of nucleotides (DNA bases) in the coding regions of a gene, which codes for an amino acid (or a stop signal during protein synthesis).
Co-segregation	The property of being inherited together within a pedigree.
Developmental verbal dyspraxia	A neurological disorder with an early onset affecting coordination of movements resulting in a linguistic impairment.
Dominant/recessive (inheritance pattern)	If one dysfunctional copy of a gene is enough to cause the disorder, where another functional copy is present, then the inheritance pattern of the particular disorder is said to be dominant. Otherwise the inheritance pattern of the disorder is said to be recessive.
fMRI	An MRI technique that measures neural activity in the brain based on the differences in the way oxygen-rich blood and oxygen-poor blood are affected by magnetic fields.
Gene family	A group of genes that share similarities in their sequences and functions.
Heterozygous/homozygous	A person carrying two identical alleles of a given gene on both chromosomes of the same type (one maternal and one paternal) is said to be homozygous for that gene. A person carrying two different alleles for the same gene is said to be heterozygous for that gene.
MicroRNA	A non-coding RNA molecule that regulates gene expression.
Missense mutation	A mutation which involves a change of a codon resulting in a codon which codes for a different amino acid.
MRI	An imaging technique that uses nuclear magnetic resonance (absorption and emission of electromagnetic radiation by nuclei affected by a magnetic field) to image the nuclei inside the subject's body.
Nonsense mutation	A mutation which involves a change of a codon resulting in a premature stop codon and, therefore, a truncated protein.
Orofacial dyspraxia	A neurological disorder in which voluntary nonverbal oral movements are impaired.
Parental imprinting effect	An effect by which the expression of a copy of a gene is dependent on which parent it was inherited from.
PET	An imaging technique which uses the radiation emitted by a radioactive tracer introduced into the living subject to produce a three-dimensional image.
Protein dimer	A protein complex formed by two protein subunits. If the units are identical, the dimer is called a homodimer; if the units are not identical, the dimer is called a heterodimer.
Transcription factor	A DNA-binding protein which regulates the expression of the genes it binds to.
Transition/transversion	A transition is a point mutation in the DNA of the form A↔G or C↔T. A transversion is a point mutation of the form C↔A,G or T↔A,G.