Consensus recommendations on mental health issues in Phelan-McDermid syndrome.

Phelan-McDermid syndrome is a rare genetic condition caused by a deletion encompassing the 22q13.3 region or a pathogenic variant of the gene SHANK3. The clinical presentation is variable, but main characteristics include global developmental delay/intellectual disability (ID), marked speech impairment or delay, along with other features like hypotonia and somatic or psychiatric comorbidities. This publication delineates mental health, developmental and behavioural themes across the lifetime of individuals with PMS as informed by parents/caregivers, experts, and other key professionals involved in PMS care. We put forward several recommendations based on the available literature concerning mental health and behaviour in PMS. Additionally, this article aims to improve our awareness of the importance of considering developmental level of the individual with PMS when assessing mental health and behavioural issues. Understanding how the discrepancy between developmental level and chronological age may impact concerning behaviours offers insight into the meaning of those behaviours and informs care for individuals with PMS, enabling clinicians to address unmet (mental health) care needs and improve quality of life.

Consensus recommendations on communication, language and speech in Phelan-McDermid syndrome.

Phelan-McDermid syndrome is a genetic condition primarily caused by a deletion on the 22q13.3 region or a likely pathogenic/pathogenic variant of SHANK3. The main features comprise global developmental delay, marked impairment or absence of speech, and other clinical characteristics to a variable degree, such as hypotonia or psychiatric comorbidities. A set of clinical guidelines for health professionals covering relevant aspects of clinical management have been written by the European PMS Consortium, and consensus has been reached regarding final recommendations. In this work, attention is given to communication, language and speech impairments in PMS, and the findings from available literature are presented. Findings from the literature review reveal marked speech impairment in up to 88% of deletions and 70% of SHANK3 variants. Absence of speech is frequent and affects 50%-80% of the individuals with PMS. Communicative skills in the expressive domain other than spoken language remain understudied, but some studies offer data on non-verbal language or the use of alternative/augmentative communication support. Loss of language and other developmental skills is reported in around 40% of individuals, with variable course. Deletion size and possibly other clinical variables (e.g., conductive hearing problems, neurological issues, intellectual disability, etc.) are related to communicative and linguistic abilities. Recommendations include regular medical check-ups of hearing and the assessment of other factors influencing communication, thorough evaluation of preverbal and verbal communicative skills, early intervention, and support via alternative/augmentative communication systems.

Characterisation of the clinical phenotype in Phelan-McDermid syndrome.

BACKGROUND: Phelan-McDermid syndrome (PMS) is a rare genetic disorder compromising the 22q13 terminal region and affecting SHANK3, a gene crucial to the neurobehavioural phenotype and strongly linked to autism (ASD) and intellectual disability (ID). The condition is characterised by global developmental delay, ID, speech impairments, hypotonia and autistic behaviours, although its presentation and symptom severity vary widely. In this study, we provide a thorough description of the behavioural profile in PMS and explore differences related to deletion size and language ability. METHODS: We used standard clinical assessment instruments to measure altered behaviour, adaptive skills and autistic symptomatology in sixty participants with PMS (30 females, median age 8.5 years, SD=7.1). We recorded background information and other clinical manifestations and explored associations with deletion size. We performed descriptive and inferential analyses for group comparison. RESULTS: We 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 associated with deletion size. CONCLUSIONS: This study adds to previous research on the clinical descriptions of PMS and supports results suggesting wide variability of symptom severity and its association with deletion size. It makes the case for suitable psychotherapeutic and pharmacological approaches, for longitudinal studies to strengthen our understanding of possible clinical courses and for more precise genomic analysis.