Genes and Mutations

Genes are the building blocks of life. They are just like recipes but instead of making a cake, genes code for proteins that have important functions in the body. FOXP1 is a specific gene found on chromosome 3 that instructs the production of the Forkhead Box P1 protein. When the gene has a change or mutation it does not function properly and the “recipe” for making the cake is changed resulting in the possibility of a variety of developmental and medical issues.

Whole exome sequencing is a single test able to identify changes or mutations in the person’s entire genetic makeup. Panel testing is able to identify changes or mutations in a subset of genes associated with a particular clinical feature (e.g., autism panel, intellectual disability panel, epilepsy panel). Mutations are most often picked up on neurodevelopmental panel tests or whole exome sequencing. In recent years both panels and whole exome sequencing has become more accessible and therefore children with developmental and or medical symptoms are being diagnosed at younger ages.

In the vast majority of FOXP1 cases, the mutation in the gene is called a de novo mutation which means that neither parent has the mutation; this de novo mutation most likely occurred spontaneously during early fetal development. This can be confirmed by genetic testing of the parents. In the case of a de novo mutation, the probability of the parents having another child with the same mutation is very low, though the affected child could as an adult pass on the mutation.


Gene Mutations

In the alphabet, different letters can be combined to produce useful and

meaningful words – but only if the letters are put together in the correct way. The same works for DNA. Certain nucleotides (the base unit of DNA) whether it is adenine (A), thymine (T), cytosine (C), or guanine (G) can be arranged in a specific manner to form the FOXP1 gene, which in turn encodes a specific protein. A missense mutation is when there is a single DNA nucleotide switch in the gene. Sometimes such a change is silent and has no effect on the protein encoded by the DNA. Other changes result in an amino acid change in the protein the gene codes for, which sometimes can profoundly change the way the protein functions.


Missense Mutations

A missense mutation is when there is a single DNA nucleotide switch in the gene. Sometimes such a change is silent and has no effect on the protein encoded by the DNA. Other changes result in an amino acid change in the protein the gene codes for, which sometimes can profoundly change the way the protein functions.


Nonsense and Frameshift Mutations

Like a missense mutation, a nonsense mutation also involves a single alteration in the DNA. However, in the case of a nonsense mutation, this single change results in the production of a stop codon, (stop codons signal the end of the protein coding sequencing), there by terminating protein synthesis (process in which cells make proteins) prematurely. The protein may not be made at all, or a shortened version of the protein may be made. Similarly, frameshift mutations arise when one or a small number of nuclootides are deleted or inserted, causing the 3-letter "words" of the gene to come out of alignment; this kind of mutation can introduce a premature stop codon, or can cause all the "downstream" words to be misread. Either outcome can result in major disruption to the way the protein functions.