A variety of genetic conditions are known to affect brain development and, consequently, might potentially exhibit behaviours related to SIDs, as they impact areas involved in sensory processing and the perceptual integration of inputs. This is the case of Williams syndrome (WS), 22q11.2 deletion syndrome (22qDS) and pseudohypoparathyroidism (PHP). Although some previous research indicates sensory processing alterations in WS [20], this area remains largely unexplored in 22qDS and PHP.
The condition 22qDS, caused by a deletion in the q11.2 region of chromosome 22, is associated with significant brain abnormalities, along with cardiac anomalies, cleft palate, immune deficiencies, cognitive difficulties, and an increased risk of psychiatric disorders such as schizophrenia [21]. Common structural alterations include hypoplasia of the corpus callosum, which impacts interhemispheric communication, and anomalies in the thalamus, affecting the relay of sensory and motor information. Additionally, structural changes in the cortical brain regions, such as variations in cortical thickness, have been observed. These structural abnormalities are linked to disruptions in neural networks and can contribute to deficits in cognitive and emotional functions, impacting development and behaviour in individuals with the syndrome [22].
WS is caused by a microdeletion in the chromosomal region 7q11.23. It is characterised by a distinctive cognitive and behavioural profile, including strong social and verbal skills, accompanied by anxiety and attention problems. Additionally, individuals with WS may present with cardiovascular anomalies, hypercalcemia in infancy, and a distinctive facial phenotype [23]. MRI studies reveal reduced brain size and a more pronounced loss of white matter compared to grey matter in WS. The posterior brain regions are notably more affected, with reduced grey matter density observed in the superior parietal lobe and hypofunction near the intraparietal sulcus, areas associated with multisensory integration and perception [24].
