SNP Shot: Genomic Insights

KBG syndrome is an uncommon condition impacting multiple areas of the body. The name "KBG" is derived from the initials of the surnames of the first families identified with the syndrome. Individuals with KBG syndrome often exhibit distinct facial characteristics, skeletal issues, and intellectual disabilities.

A hallmark of KBG syndrome is unusually large upper front teeth (macrodontia). Other notable facial features can include a broad and shortened head (brachycephaly), a face with a triangular shape, widely set eyes (hypertelorism), thick eyebrows that may merge (synophrys), a prominent bridge of the nose, an elongated area between the nose and upper lip (long philtrum), and a thin upper lip.

A frequent skeletal finding in KBG syndrome is a slower rate of bone mineralization (delayed bone age). For example, a child with KBG syndrome who is three years old may have bones that appear to be those of a two-year-old. Furthermore, individuals with the syndrome may have irregularities in the bones of the spine (vertebrae) and ribs. They may also exhibit abnormalities in the bones of their hands or feet, such as unusually short or curved pinky fingers (brachydactyly or clinodactyly, respectively) and flat feet (pes planus). Many affected individuals are shorter than expected from birth.

The development of cognitive and motor skills is also often delayed in individuals with KBG syndrome. Most affected individuals experience delays in learning to talk and walk, and they typically have mild to moderate intellectual disability. Many individuals with KBG syndrome have neurodevelopmental conditions, such as hyperactivity, anxiety, or autism spectrum disorder, characterized by challenges in communication and social interaction.

Less frequently, KBG syndrome can be associated with hearing loss, seizures, and heart problems.

Inheritance:

KBG syndrome follows an autosomal dominant inheritance pattern. This means that possessing only one copy of the mutated gene in each cell is enough to cause the disorder. An affected individual may inherit this mutation from a parent who also has the condition. In other instances, the syndrome arises from a new gene mutation in individuals with no previous family history of KBG syndrome.