Phenotypes and genotypes in individuals with SMC1A variants.

SMC1A encodes one of the proteins of the cohesin complex. SMC1A variants are known to cause a phenotype resembling Cornelia de Lange syndrome (CdLS). Exome sequencing has allowed recognizing SMC1A variants in individuals with encephalopathy with epilepsy who do not resemble CdLS. We performed an international, interdisciplinary study on 51 individuals with SMC1A variants for physical and behavioral characteristics, and compare results to those in 67 individuals with NIPBL variants. For the Netherlands all known individuals with SMC1A variants were studied, both with and without CdLS phenotype. Individuals with SMC1A variants can resemble CdLS, but manifestations are less marked compared to individuals with NIPBL variants: growth is less disturbed, facial signs are less marked (except for periocular signs and thin upper vermillion), there are no major limb anomalies, and they have a higher level of cognitive and adaptive functioning. Self-injurious behavior is more frequent and more severe in the NIPBL group. In the Dutch group 5 of 13 individuals (all females) had a phenotype that shows a remarkable resemblance to Rett syndrome: epileptic encephalopathy, severe or profound intellectual disability, stereotypic movements, and (in some) regression. Their missense, nonsense, and frameshift mutations are evenly spread over the gene. We conclude that SMC1A variants can result in a phenotype resembling CdLS and a phenotype resembling Rett syndrome. Resemblances between the SMC1A group and the NIPBL group suggest that a disturbed cohesin function contributes to the phenotype, but differences between these groups may also be explained by other underlying mechanisms such as moonlighting of the cohesin genes.

Outcomes of evaluation and testing of 660 individuals with hearing loss in a pediatric genetics of hearing loss clinic.

Hearing loss is a relatively common condition in children, occurring in approximately 2 out of every 1,000 births with approximately 50% of reported diagnoses having a primary genetic etiology. Given the prevalence and genetic component of hearing loss, coupled with a trend toward early diagnosis with the institution of universal newborn hearing screening, The Genetics of Hearing Loss Clinic was established at The Children's Hospital of Philadelphia to manage the diagnosis, testing, and genetic counseling for individuals and families. This paper described a cohort of 660 individuals with a diagnosis of hearing loss evaluated between July 2008 and July 2015 in the Genetics of Hearing Loss Clinic. To elucidate the cause of hearing loss in this cohort for better management and prognostication, testing included single nucleotide polymorphism chromosomal microarray, hearing loss next generation sequencing panel, and additional clinical tests inclusive of thyroid and renal function studies, temporal bone magnetic resonance imaging, and electrocardiogram. Of those evaluated, most had bilateral sensorineural hearing loss, occurring in 489/660 (74%). Additionally, 612/660 (93%) of patients presented with a nonsyndromic form of hearing loss (no other observed clinical findings at the time of exam), of which pathogenic mutations in GJB2 were most prevalent. Of the individuals with syndromic manifestations (48/660), Usher and Waardenburg syndrome were most commonly observed. A family history of hearing loss (first degree relative) was present in 12.6% of families with available information. Through molecular analyses, clinical examination, and laboratory testing, a definitive etiologic diagnosis was established in 157/660 (23.8%) of individuals. © 2016 Wiley Periodicals, Inc.

Attitudes about the use of internet support groups and the impact among parents of children with Cornelia de Lange syndrome.

There is an abundance of information in the literature on patient experiences with Internet support groups (ISGs). However, studies exploring these experiences in a rare disease population are scarce, even though these families are often at a disadvantage for resources, reliable information, and support. The aim of the current study was to explore the experiences with ISGs for parents of children with Cornelia de Lange syndrome (CdLS), a rare genetic diagnosis, in order to better understand the impact on emotional support and their child's medical care. Focus groups were conducted to inform the design of a large-scale internet survey. The survey asked parents closed- and open-ended questions regarding experiences with ISGs, with a focus on the psychosocial, medical, and logistical aspects. The survey found that 141/170 (82.6%) respondents have visited an Internet-based support group to find support or information about their child's CdLS diagnosis. The majority of respondents (71.7%) reported that ISGs have been helpful in finding emotional support, with the most common areas impacted as a result of ISG participation being behavior toward their children and family dynamic. Regarding medical care, most respondents (63.9%) reported that ISGs have been helpful in finding medical information and support, with the most commonly impacted areas of their child's care including day-to-day management, diet, therapy interventions, and healthcare providers. These findings provide a greater understanding of the role of Internet networking in healthcare and may inform future approaches to medical care and psychosocial support for rare, complex genetic diagnoses. © 2016 Wiley Periodicals, Inc.

Benefits and limitations of a multidisciplinary approach to individualized management of Cornelia de Lange syndrome and related diagnoses.

Given the clinical complexities of Cornelia de Lange Syndrome (CdLS), the Center for CdLS and Related Diagnoses at The Children's Hospital of Philadelphia (CHOP) and The Multidisciplinary Clinic for Adolescents and Adults at Greater Baltimore Medical Center (GBMC) were established to develop a comprehensive approach to clinical management and research issues relevant to CdLS. Little work has been done to evaluate the general utility of a multispecialty approach to patient care. Previous research demonstrates several advantages and disadvantages of multispecialty care. This research aims to better understand the benefits and limitations of a multidisciplinary clinic setting for individuals with CdLS and related diagnoses. Parents of children with CdLS and related diagnoses who have visited a multidisciplinary clinic (N = 52) and who have not visited a multidisciplinary clinic (N = 69) were surveyed to investigate their attitudes. About 90.0% of multispecialty clinic attendees indicated a preference for multidisciplinary care. However, some respondents cited a need for additional clinic services including more opportunity to meet with other specialists (N = 20), such as behavioral health, and increased information about research studies (N = 15). Travel distance and expenses often prevented families' multidisciplinary clinic attendance (N = 41 and N = 35, respectively). Despite identified limitations, these findings contribute to the evidence demonstrating the utility of a multispecialty approach to patient care. This approach ultimately has the potential to not just improve healthcare for individuals with CdLS but for those with medically complex diagnoses in general. © 2016 Wiley Periodicals, Inc.

A de novo interstitial deletion of 7q31.2q31.31 identified in a girl with developmental delay and hearing loss.

We report on a 4-year-old female who presented with unilateral sensorineural hearing loss and a concern for developmental delay. A genome-wide SNP array analysis was performed and revealed a de novo 3.2 Mb interstitial deletion of chromosome 7q31.2q31.31. This region contains thirteen protein-encoding genes. It is unknown whether haploinsufficiency of any of these genes is responsible for the clinical features of our patient. We reviewed, the clinical phenotype of a previously published 7q31.3 deletion patient and 18 additional patients with overlapping 7q31 deletions listed in the DECIPHER database. The most consistent feature in these patients and our proband is delayed speech and language development. Hearing loss is presented both in our proband and the published 7q31.3 patient. Our study suggests that a small region on chromosome 7q31.3 encompassing four genes, CFTR, CTTNBP2, NAA38, and ANKRD7, may represent a new locus for congenital hearing loss and/or speech development. © 2016 Wiley Periodicals, Inc.

NIPBL expression levels in CdLS probands as a predictor of mutation type and phenotypic severity.

Cornelia de Lange syndrome (CdLS) is a rare, genetically heterogeneous multisystem developmental disorder with a high degree of variability in its clinical presentation. Approximately 65% of probands harbor mutations in genes that encode core components (SMC1A, SMC3, and RAD21) or regulators (NIPBL, HDAC8) of the cohesin complex, of which mutations in NIPBL are the most common. Cohesin plays a canonical role in sister chromatid cohesion during cell division and non-canonical roles in DNA repair, stem cell maintenance and differentiation, and regulation of gene expression. Disruption of the latter role seems to be the major contributor to the underlying molecular pathogenesis of CdLS. NIPBL is required for loading and unloading the cohesin complex onto chromosomes. The expression levels of NIPBL itself appear to be tightly regulated and highly evolutionarily conserved. Droplet digital PCR was used to quantify NIPBL mRNA expression levels with high precision from a cohort of 37 samples (NIPBL, SMC1A, SMC3, and HDAC8 mutation positive probands and negative control). Probands with severe forms of CdLS or severe mutation types were found to have lower levels of NIPBL in comparison to phenotypically milder patients and controls. Levels of NIPBL also correlated with the presence of mutations in different CdLS-causing genes. The data suggests that NIPBL levels are closely correlated with the severity of CdLS and with specific causative genes and types of mutations. ddPCR may provide a tool to assist in diagnostic approaches to CdLS, for genetic counseling and prognosis, and for monitoring potential therapeutic modalities in the future. © 2016 Wiley Periodicals, Inc.

Interstitial deletion of 7q22.1q31.1 in a boy with structural brain abnormality, cardiac defect, developmental delay, and dysmorphic features.

This report describes a male child with a history of poor feeding and swallowing problems, hypotonia, mild bilateral sensorineural hearing loss, cerebral cortical agenesis, cardiac defects, cyanotic episodes triggered by specific movement, dysmorphic features, and developmental delays. Analysis by CytoScan HD array identified a 12.1 Mb interstitial deletion of 7q22.1q31.1 (98,779,628-110,868,171). We present a comprehensive review of the literature surrounding intermediate 7q deletions that overlap with this child's deletion, and an analysis of candidate genes in the deleted region. © 2016 Wiley Periodicals, Inc.

Characterization of limb differences in children with Cornelia de Lange Syndrome.

Cornelia de Lange syndrome (CdLS) is a well-described multisystem developmental disorder characterized by dysmorphic facial features, growth and behavioral deficits, and cardiac, gastrointestinal, and limb anomalies. The limb defects seen in CdLS can be mild, with small feet or hands only, or can be severe, with variable deficiency defects involving primarily the ulnar structures and ranging from mild hypoplasia of the fifth digit to complete absence of the forearm. Interestingly, the upper limbs are typically much more involved than the lower extremities that generally manifest with small feet and 2-3 syndactyly of the toes and shortened fourth metatarsal. The upper limbs often manifest asymmetric involvement. The limb findings in our cohort of 378 individuals with CdLS demonstrate a consistent pattern of laterality and symmetry involvement (with increased severity of right-sided limb in individuals with asymmetric limb defects) and a correlation of more significant limb defects with an increased risk of other structural anomalies, and more severe behavioral outcomes. Additionally, we found that individuals with mutations in NIPBL were most likely to have limb defects compared to mutations in other genes with nonsense, exonic deletion, and frameshift mutations being most prevalent in those with limb defects. Characterization of the limb differences in children with CdLS may provide a tool to assist in genetic counseling and determining prognosis. This paper will review the limb involvement in a large cohort of individuals with CdLS assessing the correlation with molecular etiologies, symmetry, additional structural birth defects, and cognitive outcomes. © 2016 Wiley Periodicals, Inc.

USP7 Acts as a Molecular Rheostat to Promote WASH-Dependent Endosomal Protein Recycling and Is Mutated in a Human Neurodevelopmental Disorder.

Endosomal protein recycling is a fundamental cellular process important for cellular homeostasis, signaling, and fate determination that is implicated in several diseases. WASH is an actin-nucleating protein essential for this process, and its activity is controlled through K63-linked ubiquitination by the MAGE-L2-TRIM27 ubiquitin ligase. Here, we show that the USP7 deubiquitinating enzyme is an integral component of the MAGE-L2-TRIM27 ligase and is essential for WASH-mediated endosomal actin assembly and protein recycling. Mechanistically, USP7 acts as a molecular rheostat to precisely fine-tune endosomal F-actin levels by counteracting TRIM27 auto-ubiquitination/degradation and preventing overactivation of WASH through directly deubiquitinating it. Importantly, we identify de novo heterozygous loss-of-function mutations of USP7 in individuals with a neurodevelopmental disorder, featuring intellectual disability and autism spectrum disorder. These results provide unanticipated insights into endosomal trafficking, illuminate the cooperativity between an ubiquitin ligase and a deubiquitinating enzyme, and establish a role for USP7 in human neurodevelopmental disease.

Utility and limitations of exome sequencing as a genetic diagnostic tool for conditions associated with pediatric sudden cardiac arrest/sudden cardiac death.

BACKGROUND: Conditions associated with sudden cardiac arrest/death (SCA/D) in youth often have a genetic etiology. While SCA/D is uncommon, a pro-active family screening approach may identify these inherited structural and electrical abnormalities prior to symptomatic events and allow appropriate surveillance and treatment. This study investigated the diagnostic utility of exome sequencing (ES) by evaluating the capture and coverage of genes related to SCA/D. METHODS: Samples from 102 individuals (13 with known molecular etiologies for SCA/D, 30 individuals without known molecular etiologies for SCA/D and 59 with other conditions) were analyzed following exome capture and sequencing at an average read depth of 100X. Reads were mapped to human genome GRCh37 using Novoalign, and post-processing and analysis was done using Picard and GATK. A total of 103 genes (2,190 exons) related to SCA/D were used as a primary filter. An additional 100 random variants within the targeted genes associated with SCA/D were also selected and evaluated for depth of sequencing and coverage. Although the primary objective was to evaluate the adequacy of depth of sequencing and coverage of targeted SCA/D genes and not for primary diagnosis, all patients who had SCA/D (known or unknown molecular etiologies) were evaluated with the project's variant analysis pipeline to determine if the molecular etiologies could be successfully identified. RESULTS: The majority of exons (97.6 %) were captured and fully covered on average at minimum of 20x sequencing depth. The proportion of unique genomic positions reported within poorly covered exons remained small (4 %). Exonic regions with less coverage reflect the need to enrich these areas to improve coverage. Despite limitations in coverage, we identified 100 % of cases with a prior known molecular etiology for SCA/D, and analysis of an additional 30 individuals with SCA/D but no known molecular etiology revealed a diagnostic answer in 5/30 (17 %). We also demonstrated 95 % of 100 randomly selected reported variants within our targeted genes would have been picked up on ES based on our coverage analysis. CONCLUSIONS: ES is a helpful clinical diagnostic tool for SCA/D given its potential to successfully identify a molecular diagnosis, but clinicians should be aware of limitations of available platforms from technical and diagnostic perspectives.

DYRK1A haploinsufficiency causes a new recognizable syndrome with microcephaly, intellectual disability, speech impairment, and distinct facies.

Dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 1 A (DYRK1A ) is a highly conserved gene located in the Down syndrome critical region. It has an important role in early development and regulation of neuronal proliferation. Microdeletions of chromosome 21q22.12q22.3 that include DYRK1A (21q22.13) are rare and only a few pathogenic single-nucleotide variants (SNVs) in the DYRK1A gene have been described, so as of yet, the landscape of DYRK1A disruptions and their associated phenotype has not been fully explored. We have identified 14 individuals with de novo heterozygous variants of DYRK1A; five with microdeletions, three with small insertions or deletions (INDELs) and six with deleterious SNVs. The analysis of our cohort and comparison with published cases reveals that phenotypes are consistent among individuals with the 21q22.12q22.3 microdeletion and those with translocation, SNVs, or INDELs within DYRK1A. All individuals shared congenital microcephaly at birth, intellectual disability, developmental delay, severe speech impairment, short stature, and distinct facial features. The severity of the microcephaly varied from -2 SD to -5 SD. Seizures, structural brain abnormalities, eye defects, ataxia/broad-based gait, intrauterine growth restriction, minor skeletal abnormalities, and feeding difficulties were present in two-thirds of all affected individuals. Our study demonstrates that haploinsufficiency of DYRK1A results in a new recognizable syndrome, which should be considered in individuals with Angelman syndrome-like features and distinct facial features. Our report represents the largest cohort of individuals with DYRK1A disruptions to date, and is the first attempt to define consistent genotype-phenotype correlations among subjects with 21q22.13 microdeletions and DYRK1A SNVs or small INDELs.

Loss-of-function HDAC8 mutations cause a phenotypic spectrum of Cornelia de Lange syndrome-like features, ocular hypertelorism, large fontanelle and X-linked inheritance.

Cornelia de Lange syndrome (CdLS) is a multisystem genetic disorder with distinct facies, growth failure, intellectual disability, distal limb anomalies, gastrointestinal and neurological disease. Mutations in NIPBL, encoding a cohesin regulatory protein, account for >80% of cases with typical facies. Mutations in the core cohesin complex proteins, encoded by the SMC1A, SMC3 and RAD21 genes, together account for ∼5% of subjects, often with atypical CdLS features. Recently, we identified mutations in the X-linked gene HDAC8 as the cause of a small number of CdLS cases. Here, we report a cohort of 38 individuals with an emerging spectrum of features caused by HDAC8 mutations. For several individuals, the diagnosis of CdLS was not considered prior to genomic testing. Most mutations identified are missense and de novo. Many cases are heterozygous females, each with marked skewing of X-inactivation in peripheral blood DNA. We also identified eight hemizygous males who are more severely affected. The craniofacial appearance caused by HDAC8 mutations overlaps that of typical CdLS but often displays delayed anterior fontanelle closure, ocular hypertelorism, hooding of the eyelids, a broader nose and dental anomalies, which may be useful discriminating features. HDAC8 encodes the lysine deacetylase for the cohesin subunit SMC3 and analysis of the functional consequences of the missense mutations indicates that all cause a loss of enzymatic function. These data demonstrate that loss-of-function mutations in HDAC8 cause a range of overlapping human developmental phenotypes, including a phenotypically distinct subgroup of CdLS.

Connexin 47 mutations increase risk for secondary lymphedema following breast cancer treatment.

PURPOSE: Secondary lymphedema is a frequent complication of breast cancer associated with surgery, chemotherapy, or radiation following breast cancer treatment. The potential contribution of genetic susceptibility to risk of developing secondary lymphedema following surgical trauma, radiation, and other tissue insults has not been studied. EXPERIMENTAL DESIGN: To determine whether women with breast cancer and secondary lymphedema had mutations in candidate lymphedema genes, we undertook a case-control study of 188 women diagnosed with breast cancer recruited from the University of Pittsburgh Breast Cancer Program (http://www.upmccancercenter.com/breast/index.cfm) between 2000 and 2010. Candidate lymphedema genes, GJC2 (encoding connexin 47 [Cx47]), FOXC2, HGF, MET, and FLT4 (encoding VEGFR3), were sequenced for mutation. Bioinformatics analysis and in vitro functional assays were used to confirm significance of novel mutations. RESULTS: Cx47 mutations were identified in individuals having secondary lymphedema following breast cancer treatment but not in breast cancer controls or normal women without breast cancer. These novel mutations are dysfunctional as assessed through in vitro assays and bioinformatics analysis and provide evidence that altered gap junction function leads to lymphedema. CONCLUSIONS: Our findings challenge the view that secondary lymphedema is solely due to mechanical trauma and support the hypothesis that genetic susceptibility is an important risk factor for secondary lymphedema. A priori recognition of genetic risk (i) raises the potential for early detection and intervention for a high-risk group and (ii) allows the possibility of altering surgical approach and/or chemo- and radiation therapy, or direct medical treatment of secondary lymphedema with novel connexin-modifying drugs.