For a study, the researchers aimed to provide a thorough description of the behavioral profile in PMS and explore differences related to deletion size and language ability. Researchers used standard clinical evaluation instruments to measure altered behavior, adaptive skills, and autistic symptomatology in 60 participants with PMS (30 females, median age 8.5 years, SD=7.1). Background information and other clinical manifestations were recorded, and associations with deletion size were explored. Researchers during the process found delayed gross and fine motor development, delayed and impaired language (~70% of participants non or minimally verbal), ID of different degrees, and adaptive functioning ranging from severe to borderline impairment. Approximately 40% of participants experienced developmental regression and half of those regained skills. Autistic symptoms were frequent and variable in severity, with a median ADOS-2 CSS score of 6 for every domain. Sensory processing anomalies, hyperactivity, attentional problems, and medical comorbidities were commonplace. The degree of language and motor development appeared to be related to deletion size. The researchers added to previous research on the clinical descriptions of PMS and supported results suggesting wide variability of symptom severity and its relation with deletion size. It made a case for suitable psychotherapeutic and pharmacological approaches, longitudinal outlines to strengthen our understanding of possible clinical courses, and more precise genomic analysis.