Corpus callosum dysgenesis (CCD) is a neurodevelopmental malformation characterized by the total or partial absence or hypoplasia of the corpus callosum (CC); the structure responsible for connecting both cerebral hemispheres. CCD is associated with cognitive, social, visual, auditory, motor, somatosensory and language alterations. Considering that CC seems to play an important role in the establishment of cerebral asymmetries, whether DCC patients have an indeterminate or strong handedness is an open question we addressed here.

This study aimed at investigating the influence of CCD on manual preference.

An observational study with nine DCC patients were recruited from the Instituto D'Or de Pesquisa e Ensino (Rio de Janeiro, Brazil). The Edinburgh Handedness Inventory was used to assess manual preference. The inventory has 10 items: writing, drawing, throwing, scissors, toothbrush, knife, spoom, broom, match and open a box. The laterality quotient (LQ) was applied as follows: LQ = [(R-L) / (R+L) X 100], ranging from -100 (strong left-handedness) to +100 (strong right-handedness). The statistical analysis involves data description by means of number (%) of occurrences or mean (±standard deviation).

Regarding the clinical characteristics of the sample, two types of CCD were identified: Total Agenesis (N = 6, 66.3%) and CC Hypoplasia (N = 3, 33%). Furthermore, the results showed that the type of CDD was isolated (Total Agenesis: N = 4, 44.4%; CC Hypoplasia: N = 2, 22.2%) or associated with other nervous system conditions (Total Agenesis: N = 1, 11.1%; CC Hypoplasia: N = 1, 11.1%). For manual preference, all subjects obtained the maximum score of the assessment instrument (strong left-handedness: N = 3, 33.3%; strong right-handedness: N = 6, 66.6%).

These results indicate that patients have a strong manual preference, regardless of the type of CDD and associations with nervous system conditions.

These findings can advance knowledge in the clinical condition of CCD and, consequently, influence the treatment and further research.