Speech and language phenotype in Phelan-McDermid (22q13.3) syndrome

Diagnosis and treatment of bipolar disorder in Phelan-McDermid syndrome: A case report and review of literature

BACKGROUND

Phelan-McDermid syndrome (PMS) is a rare genetic disorder characterized by intellectual disability, delayed language development, autism spectrum disorders, motor tone abnormalities, and a high risk of psychiatric symptoms, including bipolar disorder.

CASE SUMMARY

This report presented an 18-year clinical history of a 36-year-old woman with PMS, marked by intellectual disabilities, social withdrawal, and stereotyped behaviors. Diagnosed with bipolar disorder at the age of 18 years old, she encountered significant treatment challenges, including severe adverse reactions to antipsychotic medications in 2022, which led to speech and functional regression. Through rehabilitation and comprehensive therapy, her condition gradually improved. In 2024, after further treatment, her symptoms stabilized, highlighting the complexities and successes of long-term management.

CONCLUSION

Effective management of PMS requires a thorough clinical history, genetic testing, and long-term supportive care.

Adaptive functioning in children and young adults with monogenic neurodevelopmental disorders

AIM

To examine the adaptive behaviour profiles of children with monogenic neurodevelopmental disorders (NDDs) to determine whether syndrome-specific or transdiagnostic approaches provide a better understanding of the adaptive behavioural phenotypes of these NDDs.

METHOD

This cross-sectional study included parents and caregivers of 243 (48% female) individuals (age range = 1-25 years; mean = 8 years 10 months, SD = 5 years 8 months) with genetically confirmed monogenic NDDs (CDK13, DYRK1A, FOXP2, KAT6A, KANSL1, SETBP1, BRPF1, and DDX3X). Parents and caregivers completed the Vineland Adaptive Behavior Scales, Third Edition to assess communication, daily living, socialization, and motor skills.

RESULTS

Linear regression models comparing mean adaptive behaviours between monogenic NDDs, adjusting for the presence of intellectual disability, revealed few group differences. Children with variants in BRPF1 or KANSL1 had better adaptive behaviour skills compared to children with variants in CDK13, DDX3X, DYRK1A, and KAT6A, although group differences varied across domains. A latent profile analysis showed compelling evidence for a five-profile model. These profiles were homogeneous, with similar delays across the subdomain scores in each profile. Additionally, each monogenic NDD was represented in each profile, with a few exceptions.

INTERPRETATION

Transdiagnostic approaches to understand adaptive behaviour in monogenic NDDs provide a better understanding of individual strengths and challenges, enabling more targeted support.

Identification of a cryptic unbalanced translocation Der(22)t(12;22)(q24.33;q13.33) in a large Chinese family with Phelan-McDermid syndrome by nanopore sequencing

To explore the genetic cause of a four-generation severe intellectual disability in a Chinese family using nanopore sequencing and to provide genetic counseling and reproductive guidance for family members. Multiple genetic analyses of the proband and family members were performed, including chromosome karyotype analysis, whole exome sequencing, nanopore sequencing, PCR amplification, and Sanger sequencing. The results of G-binding karyotyping, CGG repeats for FMR1, GGC repeats for NOTCH2NCL, and trio-whole-exome sequencing were negative for the proband and his parents. Nanopore sequencing showed that the proband carried 12q24.33 microduplication (3.26 Mb) and 22q13.33 microdeletion (1.5 Mb). According to the guidelines of the American Society for Medical Genetics and Genomics (ACMG), the 22q13.33 microdeletion was classified as pathogenic, whereas the 12q24.33 microduplication was classified as a variant of uncertain significance (VUS). The precise karyotype and location of chromosomal breakpoints in the patient and family members were determined through PCR. According to the results of Sanger sequencing, a cryptic balanced translocation was detected in the proband's father. Additionally, informative SNPs were identified near the breakpoints for preimplantation genetic testing for structure rearrangement (PGT-SR) treatment by nanopore sequencing. We identified a cryptic unbalanced translocation in a large Chinese family with Phelan-McDermid syndrome (22q13.33 deletion syndrome) by nanopore sequencing. Nanopore sequencing can be a powerful tool for the genetic diagnosis of unexplained intellectual disability and the detection of precise breakpoints of chromosomal rearrangement in PGT-SR treatment.

Characterization of speech and language phenotype in the 8p23.1 syndrome

The 8p23.1 duplication syndrome is a rare genetic condition with an estimated prevalence rate of 1 out of 58,000. Although the syndrome was associated with speech and language delays, a comprehensive assessment of speech and language functions has not been undertaken in this population. To address this issue, the present study reports rigorous speech and language, in addition to oral-facial and developmental, assessment of a 50-month-old Turkish-speaking boy who was diagnosed with the 8p23.1 duplication syndrome. Standardized tests of development, articulation and phonology, receptive and expressive language and a language sample analysis were administered to characterize speech and language skills in the patient. The language sample was obtained in an ecologically valid, free play and conversation context. The language sample was then analyzed and compared to a database of age-matched typically-developing children (n = 33) in terms of intelligibility, morphosyntax, semantics/vocabulary, discourse, verbal facility and percentage of errors at word and utterance levels. The results revealed mild to severe problems in articulation and phonology, receptive and expressive language skills, and morphosyntax (mean length of utterance in morphemes). Future research with larger sample sizes and employing detailed speech and language assessment is needed to delineate the speech and language profile in individuals with the 8p23.1 duplication syndrome, which will guide targeted speech and language interventions.

Genetic architecture of childhood speech disorder: a review

Severe speech disorders lead to poor literacy, reduced academic attainment and negative psychosocial outcomes. As early as the 1950s, the familial nature of speech disorders was recognized, implying a genetic basis; but the molecular genetic basis remained unknown. In 2001, investigation of a large three generational family with severe speech disorder, known as childhood apraxia of speech (CAS), revealed the first causative gene; FOXP2. A long hiatus then followed for CAS candidate genes, but in the past three years, genetic analysis of cohorts ascertained for CAS have revealed over 30 causative genes. A total of 36 pathogenic variants have been identified from 122 cases across 3 cohorts in this nascent field. All genes identified have been in coding regions to date, with no apparent benefit at this stage for WGS over WES in identifying monogenic conditions associated with CAS. Hence current findings suggest a remarkable one in three children have a genetic variant that explains their CAS, with significant genetic heterogeneity emerging. Around half of the candidate genes identified are currently supported by medium (6 genes) to strong (9 genes) evidence supporting the association between the gene and CAS. Despite genetic heterogeneity; many implicated proteins functionally converge on pathways involved in chromatin modification or transcriptional regulation, opening the door to precision diagnosis and therapies. Most of the new candidate genes for CAS are associated with previously described neurodevelopmental conditions that include intellectual disability, autism and epilepsy; broadening the phenotypic spectrum to a distinctly milder presentation defined by primary speech disorder in the setting of normal intellect. Insights into the genetic bases of CAS, a severe, rare speech disorder, are yet to translate to understanding the heritability of more common, typically milder forms of speech or language impairment such as stuttering or phonological disorder. These disorders likely follow complex inheritance with polygenic contributions in many cases, rather than the monogenic patterns that underly one-third of patients with CAS. Clinical genetic testing for should now be implemented for individuals with CAS, given its high diagnostic rate, which parallels many other neurodevelopmental disorders where this testing is already standard of care. The shared mechanisms implicated by gene discovery for CAS highlight potential new targets for future precision therapies.

Updated consensus guidelines on the management of Phelan-McDermid syndrome

Phelan-McDermid syndrome (PMS) is a genetic condition caused by SHANK3 haploinsufficiency and characterized by a wide range of neurodevelopmental and systemic manifestations. The first practice parameters for assessment and monitoring in individuals with PMS were published in 2014; recently, knowledge about PMS has grown significantly based on data from longitudinal phenotyping studies and large-scale genotype-phenotype investigations. The objective of these updated clinical management guidelines was to: (1) reflect the latest in knowledge in PMS and (2) provide guidance for clinicians, researchers, and the general community. A taskforce was established with clinical experts in PMS and representatives from the parent community. Experts joined subgroups based on their areas of specialty, including genetics, neurology, neurodevelopment, gastroenterology, primary care, physiatry, nephrology, endocrinology, cardiology, gynecology, and dentistry. Taskforce members convened regularly between 2021 and 2022 and produced specialty-specific guidelines based on iterative feedback and discussion. Taskforce leaders then established consensus within their respective specialty group and harmonized the guidelines. The knowledge gained over the past decade allows for improved guidelines to assess and monitor individuals with PMS. Since there is limited evidence specific to PMS, intervention mostly follows general guidelines for treating individuals with developmental disorders. Significant evidence has been amassed to guide the management of comorbid neuropsychiatric conditions in PMS, albeit mainly from caregiver report and the experience of clinical experts. These updated consensus guidelines on the management of PMS represent an advance for the field and will improve care in the community. Several areas for future research are also highlighted and will contribute to subsequent updates with more refined and specific recommendations as new knowledge accumulates.

Pain research and children and adolescents with severe intellectual disability: ethical challenges and imperatives

Children with severe intellectual disabilities encounter inequities in pain-related care, yet little pain research involves this population. A considerable issue with pain research in this population is its ethical complexity. This Viewpoint delineates the ethical challenges of pain research involving children (aged 2-12 years) and adolescents (aged 13-21 years) with severe intellectual disabilities. There are two main issues. First, some of the standard methods for assessing pain and pain sensitivity are not suitable for individuals with severe intellectual disability, who are often non-verbal and unable to understand or follow instructions. Second, children and adolescents with severe intellectual disability cannot provide informed consent or assent to participate in pain research, and their dissent is not always recognised. The existing ethical guidelines for pain research by the International Association for the Study of Pain provide helpful, but general, guidance. This Viewpoint supplements these guidelines and uses a well established framework for assessing the ethics of clinical research to highlight points relevant to designing, doing, reviewing, and evaluating research involving children and adolescents with severe intellectual disability, focusing on issues that are unaddressed in existing guidance.

Definition and clinical variability of SHANK3-related Phelan-McDermid syndrome

Phelan-McDermid syndrome (PMS) is an infrequently described syndrome that presents with a disturbed development, neurological and psychiatric characteristics, and sometimes other comorbidities. As part of the development of European medical guidelines we studied the definition, phenotype, genotype-phenotype characteristics, and natural history of the syndrome. The number of confirmed diagnoses of PMS in different European countries was also assessed and it could be concluded that PMS is underdiagnosed. The incidence of PMS in European countries is estimated to be at least 1 in 30,000. Next generation sequencing, including analysis of copy number variations, as first tier in diagnostics of individuals with intellectual disability will likely yield a larger number of individuals with PMS than presently known. A definition of PMS by its phenotype is at the present not possible, and therefore PMS-SHANK3 related is defined by the presence of SHANK3 haploinsufficiency, either by a deletion involving region 22q13.2-33 or a pathogenic/likely pathogenic variant in SHANK3. In summarizing the phenotype, we subdivided it into that of individuals with a 22q13 deletion and that of those with a pathogenic/likely pathogenic SHANK3 variant. The phenotype of individuals with PMS is variable, depending in part on the deletion size or, whether only a variant of SHANK3 is present. The core phenotype in the domains development, neurology, and senses are similar in those with deletions and SHANK3 variants, but individuals with a SHANK3 variant more often are reported to have behavioural disorders and less often urogenital malformations and lymphedema. The behavioural disorders may, however, be a less outstanding feature in individuals with deletions accompanied by more severe intellectual disability. Data available on the natural history are limited. Results of clinical trials using insulin-like growth factor I (IGF-1), intranasal insulin, and oxytocin are available, other trials are in progress. The present guidelines for PMS aim at offering tools to caregivers and families to provide optimal care to individuals with PMS.

Consensus recommendations on altered sensory functioning in Phelan-McDermid syndrome

Altered sensory functioning is often observed in individuals with SHANK3 related Phelan-McDermid syndrome (PMS). Compared to typically developing individuals and individuals with an autism spectrum disorder, it has been suggested that there are distinctive features of sensory functioning in PMS. More hyporeactivity symptoms and less hyperreactivity and sensory seeking behaviour are seen, particularly in the auditory domain. Hypersensitivity to touch, possible overheating or turning red easily and reduced pain response are often seen. In this paper the current literature on sensory functioning in PMS is reviewed and recommendations for caregivers, based on consensus within the European PMS consortium, are given.

The Language Profile of Preschool Children With 22q11.2 Deletion Syndrome and the Relationship With Speech Intelligibility

PURPOSE

Young children with 22q11.2 deletion syndrome (22q11DS) often have impaired language development and poor speech intelligibility. Here, we report a comprehensive overview of standardized language assessment in a relatively large sample of preschool-aged children with 22q11DS. We furthermore explored whether speech ability explained variability in language skills.

METHOD

Forty-four monolingual Dutch preschoolers (3-6 years) with a confirmed genetic 22q11DS diagnosis participated in this prospective cohort study. Standardized tests (Clinical Evaluation of Language Fundamentals Preschool-2-NL and Peabody Picture Vocabulary Test-III-NL) were administered. Speech intelligibility was rated by two expert speech and language therapists using a standardized procedure.

RESULTS

Most children had impaired language skills across all tested domains. The composite score for expressive language was significantly lower than that for receptive language, but the two were strongly correlated. Only small differences between the mean scores on the various subtests were observed, with the lowest scores for expressive morphosyntactic skills. Language scores showed a moderate positive relation with speech intelligibility, but language abilities varied greatly among the children with intelligible speech.

CONCLUSIONS

We show that the majority of preschool children with 22q11DS have a broad range of language problems. Other than the relatively larger impairment in expressive than in receptive language skills, our results do not show a clearly delineated language profile. As many of the children with intelligible speech still had below-average language scores, we highlight that language problems require a broad assessment and care in all young children with 22q11DS. Future research using spontaneous language and detailed speech analysis is recommended, to provide more in-depth understanding of children's language profile and the relationship between speech and language in 22q11DS.

Social and Family Challenges of Having a Child Diagnosed with Phelan-McDermid Syndrome: A Qualitative Study of Parents' Experiences

(1) Background: Phelan-McDermid Syndrome (PMS) in children causes significant challenges affecting social and family relationships. The purpose of this study was to explore the experience of parents with children diagnosed with PMS regarding interactions with their social environment; (2) Methods: A qualitative descriptive study was conducted. Participants were recruited using non-probabilistic purposeful sampling. In total, 32 parents of children with PMS were included. In-depth interviews and researchers' field notes were used to collect the data. An inductive thematic analysis was performed; (3) Results: Five themes were identified: (a) challenges in the relationship as a couple; (b) challenges within the family and close social relationships; (c) challenges in the educational-school environment; (d) challenges in the health environment and with health professionals, and (e) reconnection through the PMS association. It would be beneficial for parents to create training programs on PMS in the educational and healthcare settings, to promote the participation of professionals in the PMS association and to develop care programs focusing in their physical, psychological and social health.

Phelan-McDermid Syndrome in Pediatric Patients With Novel Mutations: Genetic and Phenotypic Analyses

Background

PhelanrMcDermid syndrome (PMS) is an uncommon autosomal dominant inherited developmental disorder. The main characteristics are hypotonia, intellectual disability, autism spectrum disorder, autism-like behaviors and tiny facial deformities. Most cases are caused by the deletion of the 22q13 genomic region, including the deletion of SHANK3.

Methods

Genetic and phenotype evaluations of ten Chinese pediatric patients were performed. The clinical phenotypes and genetic testing results were collected statistically. We analyzed the deletion of the 22q13 genomic region and small mutations in SHANK3 (GRCh37/hg19) and performed parental genotype verification to determine whether it was related to the parents or was a novel mutation.

Results

The age of the patients diagnosed with PMS ranged from 0 to 12 years old. Nine of the pediatric patients experienced Intellectual Disability, language motion development delay and hypotonia as prominent clinical features. One subject had autism, two subjects had abnormal electroencephalogram discharge and one subject was aborted after fetal diagnosis. Three patients had a SHANK3 mutation or deletion. All but the aborted fetuses had intellectual disability. Among the ten patients, a deletion in the 22q13 region occurred in seven patients, with the smallest being 60.6 kb and the largest being >5.5 Mb. Three patients had heterozygous mutations in the SHANK3 gene.

Conclusion

All ten patients had novel mutations, and three of these were missense or frameshift mutations. For the first time reported, it is predicted that the amino acid termination code may appear before protein synthesis. The novel mutations we discovered provide a reference for clinical research and the diagnosis of PMS.

Sensory processing and adaptive behavior in Phelan-McDermid syndrome: a cross-sectional study

Phelan-McDermid syndrome (PMS) is a genetic disorder caused by a mutation or deletion of the SHANK3 gene (chromosome 22q13.3), characterized by different sensory processing anomalies. The objective of this study is to expand and provide a detailed definition of the sensory profile of patients with PMS. The secondary objective was to examine the relationship between sensory patterns and adaptive behavior. A cross-sectional study was carried out among 51 Spanish patients with a confirmed genetic diagnosis of PMS. All the participants' parents completed the Short Sensory Profile-Spanish (SSP-S) and the Adaptive Behavior Assessment System II (ABAS-II). Correlational, multiple regression and hierarchical cluster analyses were performed. An atypical sensory profile was identified in almost 75% of PMS patients. Definite differences were found among scores; nonetheless, sub-threshold values were observed in tactile sensitivity, underresponsive/seeks sensation, auditory filtering, and low energy/weak sensory categories. Conceptual, social, and practical domains, as well as the General Adaptive Composite (GAC) of the ABAS-II showed extremely low scores (i.e., <70). Significant correlations were found (p<0.005) between SSP-S scores and the conceptual, social, practical, and GAC index of the ABAS-II, whereby higher SSP-S scores were associated with better skills and higher adaptive performance. The cluster analysis indicated that the group with the largest mutation size (7.23 Mb) showed the greatest sensory processing difficulties and very low adaptive skills.

CONCLUSIONS

Patients with PMS show an atypical sensory profile, which correlates with limitations in general adaptive behaviors.

WHAT IS KNOWN

• PMS sensory processing difficulties were associated with a pattern of underresponsive/seeks sensation, low energy/weak, and tactile hyporeactivity. • Sensory processing difficulties have been associated with limitations in the development of appropriate adaptive communication and interaction behaviors.

WHAT IS NEW

• Sensory definite differences associated with tactile hyperreactivity, as well as significant effects of underresponsiveness/seeks sensation and auditory filtering categories on the adaptive abilities were found in SHANK3deletion patients. • Cluster analysis suggests that smaller mutation sizes were related to better sensory processing and higher adaptive skills, while patients with larger deletion sizes have greater adaptive difficulties and worse sensory processing skills.

Variability in Phelan-McDermid Syndrome in a Cohort of 210 Individuals

Phelan-McDermid syndrome (PMS, OMIM# 606232) results from either different rearrangements at the distal region of the long arm of chromosome 22 (22q13.3) or pathogenic sequence variants in the SHANK3 gene. SHANK3 codes for a structural protein that plays a central role in the formation of the postsynaptic terminals and the maintenance of synaptic structures. Clinically, patients with PMS often present with global developmental delay, absent or severely delayed speech, neonatal hypotonia, minor dysmorphic features, and autism spectrum disorders (ASD), among other findings. Here, we describe a cohort of 210 patients with genetically confirmed PMS. We observed multiple variant types, including a significant number of small deletions (<0.5 Mb, 64/189) and SHANK3 sequence variants (21 cases). We also detected multiple types of rearrangements among microdeletion cases, including a significant number with post-zygotic mosaicism (9.0%, 17/189), ring chromosome 22 (10.6%, 20/189), unbalanced translocations (de novo or inherited, 6.4%), and additional rearrangements at 22q13 (6.3%, 12/189) as well as other copy number variations in other chromosomes, unrelated to 22q deletions (14.8%, 28/189). We compared the clinical and genetic characteristics among patients with different sizes of deletions and with SHANK3 variants. Our findings suggest that SHANK3 plays an important role in this syndrome but is probably not uniquely responsible for all the spectrum features in PMS. We emphasize that only an adequate combination of different molecular and cytogenetic approaches allows an accurate genetic diagnosis in PMS patients. Thus, a diagnostic algorithm is proposed.

SHANK3 Genotype Mediates Speech and Language Phenotypes in a Nonclinical Population

Mutations affecting the synaptic-scaffold gene SHANK3 represent the most common genetic causes of autism with intellectual disability, accounting for about 1-2% of cases. Rare variants of this gene have also been associated with schizophrenia, and its deletion results in the autistic condition known as Phelan–McDermid syndrome. Despite the importance of SHANK3 as a paradigmatic gene mediating neurodevelopmental disorders, its psychological effects in nonclinical populations have yet to be studied. We genotyped the nonsynonymous, functional SHANK3 SNP rs9616915 in a large population of typical individuals scored for autism spectrum traits (the Autism Quotient, AQ) and schizotypy spectrum traits (the Schizotypal Personality Questionnaire, SPQ-BR). Males, but not females, showed significant genotypic effects for the SPQ-BR subscale associated with speech and language: Odd Speech. These findings, in conjunction with animal model studies showing vocalization and auditory effects of SHANK3 mutations, and studies indicating severe language alterations and speech-associated white matter tract abnormalities in Phelan–McDermid syndrome, suggest that SHANK3 differentially affects the development and expression of human language and speech. Imaging genetic and speech-language studies of typical individuals carrying different genotypes of rs9616915 should provide novel insights into the neurological and psychological bases of speech and language alterations among individuals with SHANK3 mutations and Phelan–McDermid syndrome.