Social cognition in two brothers with Becker muscular dystrophy: an exploratory study revealing divergent behavioral phenotypes.

Abstract

Only few studies investigated social cognition in Becker muscular dystrophy (BMD). However, brain dystrophin deficiency could be a neural substrate for cognitive, emotional, and neuropsychological features in BMD. We compared interoceptive accuracy and interpersonal comfort distance in two brothers with BMD presenting with the same genetic deletion and a healthy control. When possible, we collected neuropsychological and psychopathological assessments. Our BMD patients were significantly different in interoceptive accuracy, with patient 1 being extremely accurate and patient 2 being significantly less accurate than his brother but more accurate than the control. Interestingly, they presented opposite patterns of interpersonal distance. Patient 1 was comfortable with very short interpersonal distance (≤50 cm from the confederate/object) vs the control and patient 2. By contrast, patient 2 preferred larger distance vs the control and patient 1. Patient 1 also presented difficulties in social and emotional skills on the psychopathological assessment. We are aware this is a small sample; nonetheless, this is also the first description of such aspects in BMD and the first report ever of such divergent behavioral pattern. As impaired social cognition affects the quality of life and social relationship, further studies are needed for a closer understanding of involved mechanisms.