SNP Shot: Genomic Insights

FOXP2-related speech and language disorder impacts speech and language development, beginning in early childhood. Individuals with this disorder often experience apraxia, a speech problem characterized by difficulty in producing sequences of sounds, syllables, and words. This difficulty stems from irregularities in brain regions responsible for planning and coordinating lip, mouth, and tongue movements. Children with apraxia typically speak their first words later than expected, and their speech is often hard to understand initially, although clarity usually improves over time. Some affected individuals may also have difficulties with actions like coughing, sneezing, or clearing their throat.

Besides challenges in producing speech (expressive language), individuals with FOXP2-related speech and language disorder might also struggle with understanding speech (receptive language). Some may also face difficulties in other language-related areas, such as reading, writing, spelling, and grammar. In certain cases, these speech and language problems are the only features present. In other cases, individuals may also experience delays in other developmental areas, including motor skills like walking and tying shoes, or display characteristics of autism spectrum disorders, which involve difficulties with communication and social interaction.

Inheritance:

The inheritance pattern of FOXP2-related speech and language disorder varies depending on the underlying genetic cause. Mutations in the FOXP2 gene or deletions of chromosome 7 material including FOXP2 typically follow an autosomal dominant inheritance pattern. This means that only one copy of the altered gene or chromosome in each cell is enough to cause the disorder. Most often, the condition arises from a new (de novo) mutation or deletion occurring during the formation of eggs or sperm, or during early embryonic development. These cases usually appear in individuals with no family history of the disorder. Less commonly, an affected individual inherits the genetic alteration from a parent who also has the condition. In at least one large family, a FOXP2 gene mutation has been passed down across multiple generations. When FOXP2-related speech and language disorder occurs because of maternal uniparental disomy (UPD) of chromosome 7, as part of Russell-Silver syndrome, it is not inherited. UPD occurs as a random event during the formation of reproductive cells or in early embryonic development, and those with maternal UPD of chromosome 7 typically have no family history of the disorder. When the condition is due to rearrangements in the structure of chromosome 7, the inheritance pattern can be complex and depends on the specific genetic change involved.