Aortic Root Dilation and Genotype Associations in Phelan-McDermid Syndrome.

Phelan-McDermid syndrome (PMS) is a rare genetic neurodevelopmental disorder that results from the loss of one functional copy of the SHANK3 gene. While many clinical features of PMS are well-understood, there is currently limited literature on cardiovascular abnormalities in PMS. This report aims to evaluate the prevalence of aortic root dilation (ARD) among individuals with PMS and to understand if underlying genetic variation relates to risk for ARD. We present findings from 59 participants collected from a multisite observational study evaluating the phenotype and natural history of PMS. Individual echocardiographic and genetic reports were analyzed for aortic root measurements and genetic variant data, respectively. Our a priori hypothesis was that participants with chromosome 22 deletions with hg19 start coordinates on or before 49,900,000 (larger deletions) would have more instances of ARD than participants with deletion start coordinates after 49,900,000 (smaller deletions). Eight participants (14%) had ARD, and its presence was statistically significantly associated with large deletions (p = 0.047). Relatedly, participants with ARD had significantly more genes deleted on chromosome 22 than participants without ARD (p = 0.013). These results could aid in the identification of individuals with PMS who are at higher risk for ARD.

Genetics of kidney disorders in Phelan-McDermid syndrome: evidence from 357 registry participants.

BACKGROUND: Phelan-McDermid syndrome (PMS) is a rare genetic disorder caused by SHANK3 pathogenic variants or chromosomal rearrangements affecting the chromosome 22q13 region. Previous research found that kidney disorders, primarily congenital anomalies of the kidney and urinary tract, are common in people with PMS, yet research into candidate genes has been hampered by small study sizes and lack of attention to these problems. METHODS: We used a cohort of 357 people from the Phelan-McDermid Syndrome Foundation International Registry to investigate the prevalence of kidney disorders in PMS using a cross-sectional design and to identify 22q13 genes contributing to these disorders. RESULTS: Kidney disorders reported included vesicoureteral reflux (n = 37), hydronephrosis (n = 36), dysplastic kidneys (n = 19), increased kidney size (n = 19), polycystic kidneys (15 cases), and kidney stones (n = 4). Out of 315 subjects with a 22q13 deletion, 101 (32%) had at least one kidney disorder, while only one out of 42 (2%) individuals with a SHANK3 pathogenic variant had a kidney disorder (increased kidney size). We identified two genomic regions that were significantly associated with having a kidney disorder with the peak associations observed near positions approximately 5 Mb and 400 Kb from the telomere. CONCLUSIONS: The candidate genes for kidney disorders include FBLN1, WNT7B, UPK3A, CELSR1, and PLXNB2. This study demonstrates the utility of patient registries for uncovering genetic contributions to rare diseases. Future work should focus on functional studies for these genes to assess their potential pathogenic contribution to the different subsets of kidney disorders.

Living with and managing seizures among parents of children diagnosed with Phelan-McDermid syndrome: a qualitative study using in-depth interviews.

To describe the experience of parents of children diagnosed with Phelan-McDermid syndrome (PMS) in relation to epileptic seizures and/or convulsions, their daily management and impact on family life. A qualitative descriptive study was conducted. The study included parents of children diagnosed with PMS by a medical specialist. Purposive sampling was used, and data were collected via in-depth interviews. A thematic analysis was performed on the data. This study was conducted according to the Standards for Reporting Qualitative Research. Thirty-two parents were recruited. Four themes were identified: (a) the first epileptic seizure, where the first seizure appears abruptly and unexpectedly; (b) living with seizures, seizures generate high concern about the evolution of the disease and the future of children with PMS; (c) treatment of epileptic seizures, obtaining an adequate treatment is a long process that involves decision making by parents; (d) the impact of epilepsy on the family, where there is a change in the functioning and relationships among family members.  Conclusions: It is necessary to develop programs where parents can discuss treatment decisions with professionals and provide coping strategies for the management of epilepsy and seizures. What is Known: • Children with Phelan-McDermid syndrome may develop epilepsy. Parents receive insufficient information for the management and control of seizures. • Parents describe concerns about the evolution of epilepsy in their children's adulthood, along with the impact of seizures and/or convulsions on their children. What is New: • Epilepsy and seizures force the entire family to adapt their lifestyle and give up activities that can trigger seizures. • Parents pointed out the need to create programs to inform about the benefits and disadvantages of pharmacological treatments in order to improve decision making.

Sleep disturbances in Phelan-McDermid syndrome: Clinical and metabolic profiling of 56 individuals.

Phelan-McDermid Syndrome (PMS) is caused by deletions at chromosome 22q13.3 or pathogenic/likely pathogenic SHANK3 variants. The clinical presentation is extremely variable and includes global developmental delay/intellectual disability (ID), seizures, neonatal hypotonia, and sleep disturbances, among others. This study investigated the prevalence of sleep disturbances, and the genetic and metabolic features associated with them, in a cohort of 56 individuals with PMS. Sleep data were collected via standardized observer/caregiver questionnaires, while genetic data from array-CGH and sequencing of 9 candidate genes within the 22q13.3 region, and metabolic profiling utilized the Biolog Phenotype Mammalian MicroArray plates. Sleep disturbances were present in 64.3% of individuals with PMS, with the most common problem being waking during the night (39%). Sleep disturbances were more prevalent in individuals with a SHANK3 pathogenic variant (89%) compared to subjects with 22q13.3 deletions of any size (59.6%). Distinct metabolic profiles for individuals with PMS with and without sleep disturbances were also identified. These data are helpful information for recognizing and managing sleep disturbances in individuals with PMS, outlining the main candidate gene for this neurological manifestation, and highlighting potential biomarkers for early identification of at-risk subjects and molecular targets for novel treatment approaches.

Lymphedema is associated with CELSR1 in Phelan-McDermid syndrome.

Lymphedema is a troubling condition present in many disorders including the rare genetic disorder known as Phelan-McDermid syndrome (PMS). The neurobehavioral features of PMS, also known as 22q13.3 deletion syndrome, have been investigated, but little research exists on lymphedema in PMS. In this investigation, clinical and genetic data from 404 people with PMS were reviewed from the PMS-International Registry revealing a prevalence of 5% with lymphedema. Lymphedema was reported in 1 out of 47 people (2.1%) with PMS due to a SHANK3 variant and 19 out of 357 people (5.3%) with PMS due to 22q13.3 deletions. Lymphedema was more common among those in their teens or adulthood (p = 0.0011) and those with deletions >4 Mb. People with lymphedema had significantly larger deletions (mean 5.375 Mb) than those without lymphedema (mean 3.464 Mb, p = 0.00496). Association analysis identified a deletion of the CELSR1 gene to be the biggest risk factor (OR = 12.9 95% CI [2.9-56.2]). Detailed assessment of 5 subjects identified all had deletions of CELSR1, developed symptoms of lymphedema starting at age 8 or older, and typically responded well to standard therapy. In conclusion, this is the largest assessment of lymphedema in PMS to date and our results suggest that individuals with deletions >4 Mb or those with CELSR1 deletions should be assessed for lymphedema.

Rare and de novo duplications containing TCF20 are associated with a neurodevelopmental disorder.

Transcriptor co-activator factor 20 gene (TCF20) encodes a nuclear chromatin-binding protein involved in regulation of gene expression. In human pathology, pathogenic variants or deletions in TCF20 were identified in patients with developmental delay, variable intellectual disability and behavioral impairment (OMIM: 618430). The shared core phenotype includes developmental delay, hypotonia, motor delay, autism spectrum disorders, neurobehavioral anomalies, neurological features such as ataxia, seizures, movement disorders, structural brain anomalies, craniofacial features and various congenital anomalies. Most pathogenic variants are loss-of-function variants. Duplication including TCF20 was suspected to cause a neurodevelopmental disorder (NDD) with mirror traits compared to patients with TCF20 deletions. In the present study, we report three patients from three unrelated families with NDD with a de novo duplication at 22q13.2 encompassing TCF20. We propose that the TCF20 duplication could be involved in a new 22q13.2 microduplication syndrome with high penetrance, enlarging the genotype-phenotype knowledge of TCF20-associated NDDs.

Genetic and metabolic profiling of individuals with Phelan-McDermid syndrome presenting with seizures.

Phelan-McDermid syndrome (PMS) (OMIM*606232) is a rare genetic disorder characterized by intellectual disability, autistic features, speech delay, minor dysmorphia, and seizures. This study was conducted to investigate the prevalence of seizures and the association with genetic and metabolic features since there has been little research related to seizures in PMS. For 57 individuals, seizure data was collected from caregiver interviews, genetic data from existing cytogenetic records and Sanger sequencing for nine 22q13 genes, and metabolic profiling from the Phenotype Mammalian MicroArray (PM-M) developed by Biolog. Results showed that 46% of individuals had seizures with the most common type being absence and grand-mal seizures. Seizures were most prevalent in individuals with pathogenic SHANK3 mutations (70%), those with deletion sizes >4 Mb (16%), and those with deletion sizes <4 Mb (71%) suggesting involvement of genes in addition to SHANK3. Additionally, a 3 Mb genomic region on 22q13.31 containing the gene TBC1D22A, was found to be significantly associated with seizure prevalence. A distinct metabolic profile was identified for individuals with PMS with seizures and suggested among other features a disrupted utilization of main energy sources using Biolog plates. The results of this study will be helpful for clinicians and families in anticipating seizures in these children and for researchers to identify candidate genes for the seizure phenotype.

Genotype-phenotype correlation in Phelan-McDermid syndrome: A comprehensive review of chromosome 22q13 deleted genes.

Phelan-McDermid syndrome (PMS, OMIM #606232), also known as chromosome 22q13 deletion syndrome, is a rare genetic disorder characterized by intellectual disability, hypotonia, delayed or absent speech, motor impairment, autism spectrum disorder, behavioral anomalies, and minor aspecific dysmorphic features. Haploinsufficiency of SHANK3, due to intragenic deletions or point mutations, is sufficient to cause many neurobehavioral features of PMS. However, several additional genes located within larger 22q13 deletions can contribute to the great interindividual variability observed in the PMS phenotype. This review summarizes the phenotypic contributions predicted for 213 genes distributed along the largest 22q13.2-q13.33 terminal deletion detected in our sample of 63 PMS patients by array-CGH analysis, spanning 9.08 Mb. Genes have been grouped into four categories: (1) genes causing human diseases with an autosomal dominant mechanism, or (2) with an autosomal recessive mechanism; (3) morphogenetically relevant genes, either involved in human diseases with additive co-dominant, polygenic, and/or multifactorial mechanisms, or implicated in animal models but not yet documented in human pathology; (4) protein coding genes either functionally nonrelevant, with unknown function, or pathogenic through mechanisms other than haploinsufficiency; piRNAs, noncoding RNAs, miRNAs, novel transcripts and pseudogenes. Our aim is to understand genotype-phenotype correlations in PMS patients and to provide clinicians with a conceptual framework to promote evidence-based genetic work-ups, clinical assessments, and therapeutic interventions.

40-Hz Auditory Steady-State Response (ASSR) as a Biomarker of Genetic Defects in the SHANK3 Gene: A Case Report of 15-Year-Old Girl with a Rare Partial SHANK3 Duplication.

SHANK3 encodes a scaffold protein involved in postsynaptic receptor density in glutamatergic synapses, including those in the parvalbumin (PV)+ inhibitory neurons-the key players in the generation of sensory gamma oscillations, such as 40-Hz auditory steady-state response (ASSR). However, 40-Hz ASSR was not studied in relation to SHANK3 functioning. Here, we present a 15-year-old girl (SH01) with previously unreported duplication of the first seven exons of the SHANK3 gene (22q13.33). SH01's electroencephalogram (EEG) during 40-Hz click trains of 500 ms duration binaurally presented with inter-trial intervals of 500-800 ms were compared with those from typically developing children (n = 32). SH01 was diagnosed with mild mental retardation and learning disabilities (F70.88), dysgraphia, dyslexia, and smaller vocabulary than typically developing (TD) peers. Her clinical phenotype resembled the phenotype of previously described patients with 22q13.33 microduplications (≈30 reported so far). SH01 had mild autistic symptoms but below the threshold for ASD diagnosis and microcephaly. No seizures or MRI abnormalities were reported. While SH01 had relatively preserved auditory event-related potential (ERP) with slightly attenuated P1, her 40-Hz ASSR was totally absent significantly deviating from TD's ASSR. The absence of 40-Hz ASSR in patients with microduplication, which affected the SHANK3 gene, indicates deficient temporal resolution of the auditory system, which might underlie language problems and represent a neurophysiological biomarker of SHANK3 abnormalities.

Clinical and molecular characterization of an emerging chromosome 22q13.31 microdeletion syndrome.

Microdeletion of chromosome 22q13.31 is a very rare condition. Fourteen patients have been annotated in public databases but, to date, a clinical comparison has not been done and, consequently, a specific phenotype has not been delineated yet. We describe a patient showing neurodevelopmental disorders, dysmorphic features, and multiple congenital anomalies in which SNP array analysis revealed an interstitial 3.15 Mb de novo microdeletion in the 22q13.31 region encompassing 21 RefSeq genes and seven non-coding microRNAs. To perform an accurate phenotype characterization, clinical features observed in previously reported cases of 22q13.31 microdeletions were reviewed and compared to those observed in our patient. To the best of our knowledge, this is the first time that a comparison between patients carrying overlapping 22q13.31 deletions has been done. This comparison allowed us to identify a distinct spectrum of clinical manifestations suggesting that patients with a de novo interstitial microdeletion involving 22q13.31 have an emerging syndrome characterized by developmental delay/intellectual disability, speech delay/language disorders, behavioral problems, hypotonia, urogenital, and hands/feet anomalies. The microdeletion identified in our patient is the smallest reported so far and, for this reason, useful to perform a detailed genotype-phenotype correlation. In particular, we propose the CELSR1, ATXN10, FBLN1, and UPK3A as candidate genes in the onset of the main clinical features of this contiguous gene syndrome. Thus, the patient reported here broadens our knowledge of the phenotypic consequences of 22q13.31 microdeletions facilitating genotype-phenotype correlations. Additional cases are needed to corroborate our hypothesis and confirm genotype-phenotype correlations of this emerging syndrome.

A previously unrecognized 22q13.2 microdeletion syndrome that encompasses TCF20 and TNFRSF13C.

Phelan-McDermid syndrome (PMS, OMIM 606232) is a heterozygous contiguous gene microdeletion syndrome occurring at the distal region of chromosome 22q13. This deletion encompasses the SHANK3 gene at 22q13.33, which is thought to be the critical gene for the neurodevelopmental features seen in this syndrome. PMS is typically characterized by intellectual disability, autism spectrum disorder, absent to severely delayed speech, neonatal hypotonia, and dysmorphic features. Two patients presenting with classic clinical features of PMS have been reported to have interstitial microdeletions in the 22q13.2 region that map proximal to the SHANK3 gene (0.54 and 0.72 Mb, respectively). Here, we describe a 13-month-old girl with a de novo 1.16 Mb interstitial deletion in the 22q13.2 region who presented with global developmental delay, subtle dysmorphic features, and immunodeficiency. This deletion overlaps with the two previously published cases and five cases from the DECIPHER database. All eight patients share features common to patients with PMS including developmental delay and language delay, which suggests that this represents a previously unrecognized microdeletion syndrome in the 22q13.2 region. Our patient's deletion encompasses the TCF20 and TNFRSF13C genes, which are thought to play causative roles in the patient's neurodevelopmental and immunological features, respectively.

La experiencia del diagnóstico y la atención en progenitores de niños diagnosticados con el Síndrome de Phelan-McDermid: Un estudio cualitativo.

OBJETIVO: El Síndrome de Phelan-McDermid (SPMD) es una enfermedad rara, infradiagnosticada y sin cura. El propósito de este estudio fue explorar la experiencia de los progenitores con niños diagnosticados con el Síndrome de Phelan-McDermid, en relación con el proceso de diagnóstico, el tratamiento y la atención médica. MÉTODO: Se realizó un estudio cualitativo descriptivo. Los participantes fueron reclutados mediante un muestreo intencional no probabilístico. En total, se incluyeron 32 progenitores con hijos con SPMD. Se utilizaron entrevistas en profundidad y notas de campo de los investigadores. Se realizó un análisis temático inductivo. RESULTADOS: Se identificaron cinco temas: "El proceso diagnóstico", se describe el proceso diagnóstico y la forma de comunicarlo a los progenitores; "El tratamiento y sus expectativas" describe las expectativas y esperanzas construidas sobre un futuro tratamiento; "Planificación familiar", describe como los progenitores se enfrentan al consejo genético, para la planificación de tener más hijos tras el diagnóstico de SPMD; "El mundo de la discapacidad", describe la entrada de los progenitores en el entorno de la dependencia y discapacidad tras el diagnóstico; "La economía familiar", muestra las dificultades económicas debido al elevado coste de las terapias y los productos del cuidado diario. INTERPRETACIÓN: Nuestros resultados proporcionan una visión de cómo el diagnóstico y sus consecuencias son experimentados por los progenitores con niños con SPMD. Estos resultados pueden ser utilizados por los profesionales de la salud para ayudar y apoyar a los progenitores.

Novel Unbalanced Translocations Affecting the Long Arms of Chromosomes 10 and 22 Cause Complex Syndromes with Very Severe Neurodevelopmental Delay, Speech Impairment, Autistic Behavior, and Epilepsy.

Isolated abnormalities in terminal regions of chromosomes 10q and 22q were formerly described in patients affected by neuropsychological impairment, abnormal facies, and heterogeneous structural abnormalities of the body. Chromosomes 10q and 22q harbor important genes that play a major role in CNS development, like DOCK1 and SHANK3, and in overall body growth, like FGFR2 and HTRA1. By using clinical, neuroradiological, neurophysiological, and genetic assessment, we studied 3 siblings affected by 2 different forms of very severe neuropsychological impairment with structural physical abnormalities, epilepsy, and body overgrowth. The genetic analysis revealed 2 different unbalanced translocations t(10;22)(q26.13;q13.32) of genetic material between the long arms of chromosomes 10 and 22, deriving from a maternal balanced translocation. Consequences of the unbalanced translocation were the simultaneous partial monosomy of 10q26.13 to 10qter and partial trisomy of 22q13.32 to 22qter in 2 patients and the simultaneous trisomy distal q10 and monosomy distal q22 in 1 patient, respectively. To the best of our knowledge, we here describe for the first time a causal association between an unbalanced translocation t(10;22) affecting the long arms of both chromosomes 10 and 22 and a very severe neurodevelopmental delay in 3 siblings.

Mice heterozygous for an inactivated allele of the schizophrenia associated Brd1 gene display selective cognitive deficits with translational relevance to schizophrenia.

Schizophrenia is a debilitating brain disorder characterized by disturbances of emotion, perception and cognition. Cognitive impairments predict functional outcome in schizophrenia and are detectable even in the prodromal stage of the disorder. However, our understanding of the underlying neurobiology is limited and procognitive treatments remain elusive. We recently demonstrated that mice heterozygous for an inactivated allele of the schizophrenia-associated Brd1 gene (Brd1+/- mice) display behaviors reminiscent of schizophrenia, including impaired social cognition and long-term memory. Here, we further characterize performance of these mice by following the preclinical guidelines recommended by the 'Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS)' and 'Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS)' initiatives to maximize translational value. Brd1+/- mice exhibit relational encoding deficits, compromised working and long term memory, as well as impaired executive cognitive functioning with cognitive behaviors relying on medial prefrontal cortex being particularly affected. Akin to patients with schizophrenia, the cognitive deficits displayed by Brd1+/- mice are not global, but selective. Our results underline the value of Brd1+/- mice as a promising tool for studying the neurobiology of cognitive deficits in schizophrenia.

Genotype-phenotype correlation of 16p13.3 terminal duplication and 22q13.33 deletion: Natural history of a patient and review of the literature.

This article reports a patient with a de novo ∼ 9.32 Mb duplication at 16p13.3 and a ∼ 71 Kb deletion at 22q13.33. The patient was followed from 1 month old to 3 years and 8 months of age and presented typical features of the 16p13.3 duplication syndrome. In addition, the patient presents a portal cavernoma, an alteration rarely reported in this condition. Renal agenesis was detected as additional developmental defect. After genomic array and FISH analysis, the karyotype was 46,XX,ins(22;16)(q13;p13.2p13.3). ish ins(22;16)(RP11-35P16+, RP11-27M24+). arr16p13.2p13.3(85,880-9,413,353)×3 dn arr22q13.33 (51,140,789-51,197,838)×1 dn. The authors provide a comprehensive review of the literature. This approach shed light on the genotype-phenotype correlation.

A 9-year-old-girl with Phelan McDermid Syndrome, who had been diagnosed with an autism spectrum disorder.

Phelan McDermid Syndrome (PHMDS) (OMIM #606232), is a contiguous gene disorder resulting from deletion of the distal long arm of chromosome 22. The 22q13.3 deletions and mutations that lead to a loss of a functional copy of SHANK3 (OMIM *606230) cause the syndrome, characterized by moderate to profound intellectual disability, severely delayed or absent speech, hypotonia, and autism spectrum disorder (ASD) or ASD traits. In this study, we present the case of a 9-year-old girl who had earlier been diagnosed with an ASD. Our findings were a clinically mild intellectual disability, rounded face, pointed chin but no autistic findings. We learned that her neuromotor development was delayed and she had neonatal hypotonia in her history. A heterozygous deletion of MLC1, SBF1, MAPK8IP2, ARSA, SHANK3 and ACR genes, located on 22q13.33, was defined by multiplex ligation-dependent probe amplification (MLPA). Deletion of 22q13.3 (ARSA) region was confirmed by a fluorescent in situ hybridization (FISH) technique. The 22q13.3 deletion was found to be de novo in our patient, and she was diagnosed with PHMDS. We confirmed the 22q13.3 deletion and also determined a gain of 8p23.3-23.2 by array comparative genomic hybridization (aCGH). Fluorescent in situ hybridization was performed to determine whether the deletion was of parental origin and to identify regions of chromosomes where the extra 8p may have been located. The parents were found to be normal. The extra copy of 8p was observed on 22q in the patient. She is the first case reported in association with the 22q deletion of 8p duplications in the literature.

A patient with the classic features of Phelan-McDermid syndrome and a high immunoglobulin E level caused by a cryptic interstitial 0.72-Mb deletion in the 22q13.2 region.

Phelan-McDermid syndrome, also known as the 22q13 deletion syndrome, is a chromosomal microdeletion syndrome characterized by neonatal hypotonia, normal growth, profound developmental delay, absent or delayed speech, and minor dysmorphic features. Almost all of the 22q13 deletions published so far have been described as terminal. It is believed that the SHANK3 gene is the major candidate gene for the neurologic features of the syndrome. Here we describe a patient with a 0.72-Mb interstitial 22q13.2 deletion, intellectual disability, autistic behavior, epilepsy, mild dysmorphic features, and no deletion in the SHANK3 gene. The patient also has urticarial rash and an elevated level of immunoglobulin E, the latter has previously been described only once in a patient with monosomy 22q13.2-qter and SHANK3 gene deletion. To our knowledge, this is one of the smallest interstitial deletion in this region which has been published up to now. Although the patient has the classic phenotype of the 22q13 terminal deletion syndrome, the etiology for the neurologic and immunological features must be due to genes located more proximal to SHANK3 and this is also supported by other previously published cases of interstitial 22q13.2 deletions. The deleted area in our patient is gene-rich (26 genes), containing several known genes with different functions. Two of them-NFAM1 and TNFRSF13C are involved in immune system functioning. We suggest the haploinsufficiency of these genes might be related to hyper IgE syndrome in our patient.

Clinical, cytogenetic, and molecular characterization of six patients with ring chromosomes 22, including one with concomitant 22q11.2 deletion.

We report here on six patients with a ring chromosome 22 and the range of cytogenetic and phenotypic features presented by them. Genomic analysis was carried out using classical and molecular cytogenetics, MLPA (Multiplex Ligation-dependent Probe Amplification) and genome-wide SNP-array analysis. The ring was found in all patients, but Patient 6 displayed constitutional mosaicism with a normal cell line. Five patients had deletions in the ring chromosome 22, and in four of them the breakpoints--unique for each patient--could be identified by genome-wide SNP-array analysis. One patient presented with a 22q11.2 deletion concomitant with the deletion caused by the ring formation. Common phenotypic features included autism, speech delay and seizures, as previously reported for individuals with r(22) and/or 22q13.3 deletions. Investigation of the genes within the deletions revealed multiple genes related to development of the central nervous system, psychomotor delay, severe language impairment, hypotonia, and autistic symptoms. There was no clear correlation between the severity of clinical features and the size of the deleted segment. This study underscores the variability in ring structure and clinical presentation of the r(22) and adds information to the limited literature on this rare disorder.

Interstitial 22q13 deletions not involving SHANK3 gene: a new contiguous gene syndrome.

Phelan-McDermid syndrome (22q13.3 deletion syndrome) is a contiguous gene disorder resulting from the deletion of the distal long arm of chromosome 22. SHANK3, a gene within the minimal critical region, is a candidate gene for the major neurological features of this syndrome. We report clinical and molecular data from a study of nine patients with overlapping interstitial deletions in 22q13 not involving SHANK3. All of these deletions overlap with the largest, but not with the smallest deletion associated with Phelan-McDermid syndrome. The deletion sizes and breakpoints varied considerably among our patients, with the largest deletion spanning 6.9 Mb and the smallest deletion spanning 2.7 Mb. Eight out of nine patients had a de novo deletion, while in one patient the origin of deletion was unknown. These patients shared clinical features common to Phelan-McDermid syndrome: developmental delay (11/12), speech delay (11/12), hypotonia (9/12), and feeding difficulties (7/12). Moreover, the majority of patients (8/12) exhibited macrocephaly. In the minimal deleted region, we identified two candidate genes, SULT4A1 and PARVB (associated with the PTEN pathway), which could be associated in our cohort with neurological features and macrocephaly/hypotonia, respectively. This study suggests that the haploinsufficiency of genes in the 22q13 region beside SHANK3 contributes to cognitive and speech development, and that these genes are involved in the phenotype associated with the larger Phelan-McDermid syndrome 22q13 deletions. Moreover, because the deletions in our patients do not involve the SHANK3 gene, we posit the existence of a new contiguous gene syndrome proximal to the smallest terminal deletions in the 22q13 region.

Clinical, genetic, and cognitive correlates of seizure occurrences in Phelan-McDermid syndrome.

BACKGROUND: Phelan-McDermid syndrome (PMS) is a genetic neurodevelopmental disorder caused by SHANK3 haploinsufficiency and is associated with an increased risk for seizures. Previous literature indicates that around one third of individuals with PMS also have epilepsy or seizures, with a wide range of types and ages of onset. Investigating the impact of seizures on intellectual and adaptive functioning for PMS is a primary concern for caregivers and is important to understanding the natural history of this syndrome. METHODS: We report on results from 98 individuals enrolled in a prospective, longitudinal study. We detailed seizure frequency, type, and age of onset, and we analyzed seizure occurrence with best estimate IQ, adaptive functioning, clinical features, and genotype. We conducted multiple linear regression analyses to assess the relationship between the presence of seizures and the Vineland Adaptive Behavior Scale, Second Edition (VABS-II) Adaptive Behavior Composite score and the best estimate full-scale IQ. We also performed Chi-square tests to explore associations between seizure prevalence and genetic groupings. Finally, we performed Chi-square tests and t-tests to explore the relationship between seizures and demographic features, features that manifest in infancy, and medical features. RESULTS: Seizures were present in 41% of the cohort, and age of onset was widely variable. The presence of seizures was associated with significantly lower adaptive and intellectual functioning. Genotype-phenotype analyses were discrepant, with no differences in seizure prevalence across genetic classes, but with more genes included in deletions of participants with 22q13 deletions and seizures compared to those with 22q13 deletions and no seizures. No clinical associations were found between the presence of seizures and sex, history of pre- or neonatal complications, early infancy, or medical features. In this cohort, generalized seizures were associated with developmental regression, which is a top concern for PMS caregivers. CONCLUSIONS: These results begin to eludicate correlates of seizures in individuals with PMS and highlight the importance of early seizure management. Importantly, presence of seizures was associated with adaptive and cognitive functioning. A larger cohort might be able to identify additional associations with medical features. Genetic findings suggest an increased capability to realize genotype-phenotype relationships when deletion size is taken into account.