SNP Shot: Genomic Insights

Baraitser-Winter syndrome is a developmental disorder that impacts various areas of the body, most notably the face and brain.

The most prevalent symptom of Baraitser-Winter syndrome is an atypical facial appearance. These characteristic features may include widely set eyes (hypertelorism), large palpebral fissures, drooping eyelids (ptosis), prominent eyebrows with a high arch, a wide nasal bridge and tip, a long philtrum (the area between the nose and upper lip), prominent cheeks, and a pointed chin.

In the majority of individuals with Baraitser-Winter syndrome, structural brain irregularities are observed. These abnormalities stem from disruptions in neuronal migration, a process crucial for nerve cells (neurons) to reach their correct locations during brain development. Pachygyria, an area of the brain exhibiting an unusually smooth surface with fewer folds, is the most common brain anomaly associated with this syndrome. Less frequently, individuals may present with lissencephaly, a condition similar to pachygyria but affecting the entire brain's surface. These structural alterations can lead to varying degrees of intellectual disability, developmental delays, and seizures.

Additional features of Baraitser-Winter syndrome can encompass short stature, ear malformations and hearing impairment, cardiac abnormalities, the presence of an extra thumb (duplication), and kidney and urinary tract problems. Some individuals affected by this condition may experience restricted movement in major joints like the elbows and knees, either from birth or developing over time. In rare instances, involuntary muscle contractions (dystonia) may occur.

Inheritance:

This condition follows an autosomal dominant inheritance pattern. This means that only one copy of the mutated gene in each cell is enough to cause the disorder. Typically, the condition arises from new (de novo) mutations in either the ACTB or ACTG1 gene, occurring in individuals with no prior family history of the syndrome.