Cognitive function in DMD carriers: personal case series and literature review

Improvement in clinical conditions allowed physicians to pay more attention to the cognitive function in DMD patients, leading to description of a cognitive impairment not only in affected males, but in female carriers as well. This study aimed to investigate the cognitive involvement in a cohort of DMD carriers and to summarize the current knowledge about the intellectual involvement and neuropsychological profile in DMD/BMD carriers. Our case series consisted of 22 carrier patients from two different centers (IRCCS Mondino, Pavia and Policlinico Gemelli, Rome), for whom we retrospectively collected cognitive, clinical and genetic data. For literature review, we selected 9 studies published in English language from 2011 to 2023 and cited in PubMed. We found that the average IQ of DMD carriers was lower (74; very low) than the average score on normal curve (100 as average standard score). Furthermore, about 50% of them fell in the "extremely low IQ" range, compared with 2-3% of general population. A higher incidence of intellectual disability was confirmed in symptomatic DMD carriers (mean IQ 66; extremely low) from IRCCS Mondino, but not in the asymptomatic ones (mean IQ 99; average), when compared to the general population. Current literature, albeit limited, seems to confirm the presence of a cognitive impairment in carriers, although milder than in affected males but with a similar neuropsychological profile. However, further studies are necessary to delve deeper into this issue and provide adequate educational support.