Double somatic mosaicism in Cornelia de Lange syndrome.

Post-zygotic mosaicism is a well-known biological phenomenon characterized by the presence of genetically distinct lineages of cells in the same individual due to post-zygotic de novo mutational events. It has been identified in about 13% of Cornelia de Lange (CdLS) syndrome patients with a molecular diagnosis, an unusual high frequency. Here, we report the case of a patient affected by classic CdLS harboring post-zygotic mosaicism for two different likely pathogenic variants at the same nucleotide position in NIPBL. Double somatic mosaicism has never been reported in CdLS and only rarely recognized in human diseases. Possible pathogenetic mechanisms are discussed.

Diagnosis and management of Cornelia de Lange syndrome: first international consensus statement.

Cornelia de Lange syndrome (CdLS) is an archetypical genetic syndrome that is characterized by intellectual disability, well-defined facial features, upper limb anomalies and atypical growth, among numerous other signs and symptoms. It is caused by variants in any one of seven genes, all of which have a structural or regulatory function in the cohesin complex. Although recent advances in next-generation sequencing have improved molecular diagnostics, marked heterogeneity exists in clinical and molecular diagnostic approaches and care practices worldwide. Here, we outline a series of recommendations that document the consensus of a group of international experts on clinical diagnostic criteria, both for classic CdLS and non-classic CdLS phenotypes, molecular investigations, long-term management and care planning.

Genotypes and phenotypes heterogeneity in PIK3CA-related overgrowth spectrum and overlapping conditions: 150 novel patients and systematic review of 1007 patients with PIK3CA pathogenetic variants.

BACKGROUND: Postzygotic activating PIK3CA variants cause several phenotypes within the PIK3CA-related overgrowth spectrum (PROS). Variant strength, mosaicism level, specific tissue involvement and overlapping disorders are responsible for disease heterogeneity. We explored these factors in 150 novel patients and in an expanded cohort of 1007 PIK3CA-mutated patients, analysing our new data with previous literature to give a comprehensive picture. METHODS: We performed ultradeep targeted next-generation sequencing (NGS) on DNA from skin biopsy, buccal swab or blood using a panel including phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin pathway genes and GNAQ, GNA11, RASA1 and TEK. Additionally, 914 patients previously reported were systematically reviewed. RESULTS: 93 of our 150 patients had PIK3CA pathogenetic variants. The merged PROS cohort showed that PIK3CA variants span thorough all gene domains, some were exclusively associated with specific PROS phenotypes: weakly activating variants were associated with central nervous system (CNS) involvement, and strongly activating variants with extra-CNS phenotypes. Among the 57 with a wild-type PIK3CA allele, 11 patients with overgrowth and vascular malformations overlapping PROS had variants in GNAQ, GNA11, RASA1 or TEK. CONCLUSION: We confirm that (1) molecular diagnostic yield increases when multiple tissues are tested and by enriching NGS panels with genes of overlapping 'vascular' phenotypes; (2) strongly activating PIK3CA variants are found in affected tissue, rarely in blood: conversely, weakly activating mutations more common in blood; (3) weakly activating variants correlate with CNS involvement, strong variants are more common in cases without; (4) patients with vascular malformations overlapping those of PROS can harbour variants in genes other than PIK3CA.

ARF1-related disorder: phenotypic and molecular spectrum.

PURPOSE: ARF1 was previously implicated in periventricular nodular heterotopia (PVNH) in only five individuals and systematic clinical characterisation was not available. The aim of this study is to provide a comprehensive description of the phenotypic and genotypic spectrum of ARF1-related neurodevelopmental disorder. METHODS: We collected detailed phenotypes of an international cohort of individuals (n=17) with ARF1 variants assembled through the GeneMatcher platform. Missense variants were structurally modelled, and the impact of several were functionally validated. RESULTS: De novo variants (10 missense, 1 frameshift, 1 splice altering resulting in 9 residues insertion) in ARF1 were identified among 17 unrelated individuals. Detailed phenotypes included intellectual disability (ID), microcephaly, seizures and PVNH. No specific facial characteristics were consistent across all cases, however microretrognathia was common. Various hearing and visual defects were recurrent, and interestingly, some inflammatory features were reported. MRI of the brain frequently showed abnormalities consistent with a neuronal migration disorder. CONCLUSION: We confirm the role of ARF1 in an autosomal dominant syndrome with a phenotypic spectrum including severe ID, microcephaly, seizures and PVNH due to impaired neuronal migration.

Rock around DYRK1A: Ethnic diversity, clinical challenges.

DYRK1A-related intellectual disability is a recently described syndrome characterized by microcephaly, global developmental delay, impaired speech development, and distinctive facial features, which let to define it as a recognizable syndrome. Here we report four new patients of different ethnicity, broadening the clinical phenotype of the condition and highlighting how ethnic influences in the facial appearance could make it less recognizable.

Celiac disease prevalence and predisposing-HLA in a cohort of 93 Williams-Beuren syndrome patients.

Williams-Beuren syndrome is considered to be at increased risk for celiac disease, as for recent literature data and celiac disease guidelines, despite pathogenic mechanisms are still unclear. Our study analyzed the prevalence of autoimmune disorders, HLA DQ2 and/or DQ8 haplotypes, of transglutaminase antibodies and of diagnosis of celiac disease in a cohort of 93 Williams-Beuren syndrome's patients (mean age 21.26 years). Our study showed an increased prevalence of celiac disease equal to 10.8% (10/93 patients). We did not find a significant different frequency of predisposing HLA in subjects with Williams-Beuren syndrome compared to literature data in the general population (49.5% vs. 42.9%, with p > .1), nor a susceptibility to autoimmunity. This suggests that the increased prevalence of celiac disease in Williams-Beuren syndrome cannot be ascribed to HLA haplotype and may be related to other factors that still need to be identified in these patients.

Defining the genotypic and phenotypic spectrum of X-linked MSL3-related disorder.

PURPOSE: We sought to delineate the genotypic and phenotypic spectrum of female and male individuals with X-linked, MSL3-related disorder (Basilicata-Akhtar syndrome). METHODS: Twenty-five individuals (15 males, 10 females) with causative variants in MSL3 were ascertained through exome or genome sequencing at ten different sequencing centers. RESULTS: We identified multiple variant types in MSL3 (ten nonsense, six frameshift, four splice site, three missense, one in-frame-deletion, one multi-exon deletion), most proven to be de novo, and clustering in the terminal eight exons suggesting that truncating variants in the first five exons might be compensated by an alternative MSL3 transcript. Three-dimensional modeling of missense and splice variants indicated that these have a deleterious effect. The main clinical findings comprised developmental delay and intellectual disability ranging from mild to severe. Autism spectrum disorder, muscle tone abnormalities, and macrocephaly were common as well as hearing impairment and gastrointestinal problems. Hypoplasia of the cerebellar vermis emerged as a consistent magnetic resonance image (MRI) finding. Females and males were equally affected. Using facial analysis technology, a recognizable facial gestalt was determined. CONCLUSION: Our aggregated data illustrate the genotypic and phenotypic spectrum of X-linked, MSL3-related disorder (Basilicata-Akhtar syndrome). Our cohort improves the understanding of disease related morbidity and allows us to propose detailed surveillance guidelines for affected individuals.

A novel nonsense and inactivating variant of ST3GAL3 in two infant siblings suffering severe epilepsy and expressing circulating CA19.9.

Three missense variants of ST3GAL3 are known to be responsible for a congenital disorder of glycosylation determining a neurodevelopmental disorder (intellectual disability/epileptic encephalopathy). Here we report a novel nonsense variant, p.Y220*, in two dichorionic infant twins presenting a picture of epileptic encephalopathy with impaired neuromotor development. Upon expression in HEK-293T cells, the variant appears totally devoid of enzymatic activity in vitro, apparently accumulated with respect to the wild-type or the missense variants, as detected by western blot, and in large part properly localized in the Golgi apparatus, as assessed by confocal microscopy. Both patients were found to efficiently express the CA19.9 antigen in the serum despite the total loss of ST3GAL3 activity, which thus appears replaceable from other ST3GALs in the synthesis of the sialyl-Lewis a epitope. Kinetic studies of ST3GAL3 revealed a strong preference for lactotetraosylceramide as acceptor and gangliotetraosylceramide was also efficiently utilized in vitro. Moreover, the p.A13D missense variant, the one maintaining residual sialyltransferase activity, was found to have much lower affinity for all suitable substrates than the wild-type enzyme with an overall catalytic efficiency almost negligible. Altogether the present data suggest that the apparent redundancy of ST3GALs deduced from knock-out mouse models only partially exists in humans. In fact, our patients lacking ST3GAL3 activity synthesize the CA19.9 epitope sialyl-Lewis a, but not all glycans necessary for fine brain functions, where the role of minor gangliosides deserves further attention.

Phenotypic spectrum and transcriptomic profile associated with germline variants in TRAF7.

PURPOSE: Somatic variants in tumor necrosis factor receptor-associated factor 7 (TRAF7) cause meningioma, while germline variants have recently been identified in seven patients with developmental delay and cardiac, facial, and digital anomalies. We aimed to define the clinical and mutational spectrum associated with TRAF7 germline variants in a large series of patients, and to determine the molecular effects of the variants through transcriptomic analysis of patient fibroblasts. METHODS: We performed exome, targeted capture, and Sanger sequencing of patients with undiagnosed developmental disorders, in multiple independent diagnostic or research centers. Phenotypic and mutational comparisons were facilitated through data exchange platforms. Whole-transcriptome sequencing was performed on RNA from patient- and control-derived fibroblasts. RESULTS: We identified heterozygous missense variants in TRAF7 as the cause of a developmental delay-malformation syndrome in 45 patients. Major features include a recognizable facial gestalt (characterized in particular by blepharophimosis), short neck, pectus carinatum, digital deviations, and patent ductus arteriosus. Almost all variants occur in the WD40 repeats and most are recurrent. Several differentially expressed genes were identified in patient fibroblasts. CONCLUSION: We provide the first large-scale analysis of the clinical and mutational spectrum associated with the TRAF7 developmental syndrome, and we shed light on its molecular etiology through transcriptome studies.

Complex nutritional deficiencies in a large cohort of Italian patients with Cornelia de Lange syndrome spectrum.

Cornelia de Lange syndrome Spectrum (CdLSp) is characterized by intellectual disability, facial dysmorphisms, and growth impairment. Although eating difficulties are a well-known feature of the disease, there is no data regarding the nutritional deficiencies of these patients. The food intake was tracked using a dietary transcription provided by the family/caregivers, biochemical nutritional parameters were measured with laboratory tests and through an accurate clinical evaluation of the incidence of qualitative and quantitative imbalances in a cohort of 73 patients with CdLSp ware determined. Of these 73, 62 (85%) subjects provided a complete and detailed dietary transcription. In the studied population, a quantitative caloric imbalance in 47/62 (76%) subjects was observed. The caloric intake was low in 27/62 (43%) subjects whereas excessive in 20/62 (33%). Only 15/62 (24%) had an optimum caloric intake. Regarding micronutrients, a calcium intake deficiency in 32% of the patients (20/62) was observed. Blood tests revealed a low iron level in 22/73 (30%) of the patients and 25(OH)D deficiency in 49/73 (67%). Serum hypocalcemia was not evidenced. Qualitative and quantitative imbalances resulted in more frequent than expected in CdLSp patients. A qualitative imbalance was more prevalent in younger patients while in older patients prevailed mainly a quantitative disproportion. We found no statistically meaningful correlation between dietary imbalances, genetic, or clinical parameters. Our findings highlight the need for further studies to evaluate the basal metabolic rate of CdLSp patients and find a correlation with their growth impairment.

Nissen fundoplication in Cornelia de Lange syndrome spectrum: Who are the potential candidates?

Cornelia de Lange spectrum (CdLSp) is a rare genetic condition characterized by intellectual disability, facial dysmorphisms, major malformations, growth impairment, and development delay. Approximately 80% of CdLSp patients have gastroesophageal reflux disease (GERD) with a varied clinical presentation. The aim of this study is to define potential clinical/genetic risk factors based on the clinical phenotype description of CdLSp patients with severe GERD who underwent surgical treatment. We retrospectively collected data from 23 CdLSp patients, 13 females and 10 males. Mean age of the patients undergoing surgical treatment was of 4 years. 21/23 (91%) had a molecular characterization, of which 21/21 (100%) had a NIPBL gene mutation, while 2/23 (9%) did not have a genetical characterization, only a clinical diagnosis. Most of our patients presented a moderate-severe severity score (21/23, 91%) with limb malformations evidenced in 10/23 (44%) of our patients and a moderate-severe intellectual disability in 20/23 (87%). Therefore, CdLSp patients harboring NIPBL variants, upper limb malformations and severe psychomotor delay are more likely to suffer from severe GERD, not responsive to proton pump inhibitors treatment. These features should be considered as clinical markers for potentially severe GERD that might require surgical treatment.

Cohesin complex-associated holoprosencephaly.

Marked by incomplete division of the embryonic forebrain, holoprosencephaly is one of the most common human developmental disorders. Despite decades of phenotype-driven research, 80-90% of aneuploidy-negative holoprosencephaly individuals with a probable genetic aetiology do not have a genetic diagnosis. Here we report holoprosencephaly associated with variants in the two X-linked cohesin complex genes, STAG2 and SMC1A, with loss-of-function variants in 10 individuals and a missense variant in one. Additionally, we report four individuals with variants in the cohesin complex genes that are not X-linked, SMC3 and RAD21. Using whole mount in situ hybridization, we show that STAG2 and SMC1A are expressed in the prosencephalic neural folds during primary neurulation in the mouse, consistent with forebrain morphogenesis and holoprosencephaly pathogenesis. Finally, we found that shRNA knockdown of STAG2 and SMC1A causes aberrant expression of HPE-associated genes ZIC2, GLI2, SMAD3 and FGFR1 in human neural stem cells. These findings show the cohesin complex as an important regulator of median forebrain development and X-linked inheritance patterns in holoprosencephaly.

Diagnostic Yield of an Algorithm for Neonatal and Infantile Cholestasis Integrating Next-Generation Sequencing.

OBJECTIVE: To evaluate the performance of a diagnostic protocol for neonatal/infantile cholestasis in which the main clinical patterns steered the early use of different genetic testing strategies. STUDY DESIGN: An observational study was conducted between 2012 and 2017 in a tertiary care setting on a prospective cohort of children with cholestasis occurring at ≤1 year of age and persisting ≥6 weeks, to measure the detection rate of underlying monogenic diseases. After the exclusion of biliary atresia, a clinically driven genetic testing was performed, entailing 3 different approaches with different wideness: confirmatory single-gene testing; focused virtual panels; and wide search through trio whole-exome sequencing. RESULTS: We enrolled 125 children (66 female, median age 2 months); 96 (77%) patients had hypocholic stools and were evaluated rapidly to exclude biliary atresia, which was the final diagnosis in 74 (59%). Overall, 50 patients underwent genetic testing, 6 with single confirmatory gene testing, 38 through panels, and 6 with trio whole-exome sequencing because of complex phenotype. The genetic testing detection rate was 60%: the final diagnosis was Alagille syndrome in 11, progressive familial intrahepatic cholestasis type 2 in 6, alpha-1-antitrypsin deficiency in 3, and progressive familial intrahepatic cholestasis type 3 in 2; a further 7 genetic conditions were identified in 1 child each. Overall, only 18 of 125 (14%) remained with an indeterminate etiology. CONCLUSIONS: This protocol combining clinical and genetic assessment proved to be an effective diagnostic tool for neonatal/infantile cholestasis, identifying inherited disorders with a high detection rate. It also could allow a noninvasive diagnosis in children presenting with colored stools.

Atypical presentation of pediatric BRAF RASopathy with acute encephalopathy.

We report a 9-year-old girl with hypotonia, severe motor delay, absent speech, and facial dysmorphism who developed acute encephalopathy with severe neurological outcome. Trio-based whole exome sequencing (WES) analysis detected a de novo heterozygous mutation in the BRAF gene leading to the diagnosis of an atypical presentation of cardiofaciocutaneous (CFC) syndrome. This is the second case of CFC syndrome complicated with acute encephalopathy reported in the literature and supports the hypothesis that acute encephalopathy might be one of the complications of the syndrome due to an intrinsic susceptibility to this acute event. The report furthermore highlights the role of WES in providing a fast diagnosis in patients in critical conditions with atypical presentation of rare genetic syndromes.

Use of nutritional devices in Cornelia de Lange syndrome: Data from a large Italian cohort.

Cornelia de Lange syndrome (CdLS) is a genetic condition characterized by intellectual disability, peculiar facial dysmorphisms, multiorgan malformations, and growth problems. Majority cases of CdLS are caused by mutations in genes of Cohesin pathway. Although feeding problems are a well-known feature, no specific data have been published about the use of nutritional devices. We analyzed use, type, time of introduction, and duration of nutritional devices in 73 CdLS patients. In total, 29/73 (40%) used a device; nasogastric tube (NGT) in 28/73 (38%) and percutaneous endoscopic gastrostomy (PEG) in 7/73 (10%). NGT was placed during the first days/weeks of life. 19/28 (68%) maintained it for less than 3 months, 7/28 (25%) for a period between 3 and 12 months, while 2/28 (7%) for more than 1 year. PEG was placed within the first year in 4/7 (57%) and removed in two patients after 4 years These data have been matched with a wide number of genetic and clinical variables. Presence of upper limb malformations is positively correlated with the need of a device. From the opposite side, the use of a device positively correlates with a more severe prognosis as regard growth, intellectual development and disease severity. Our data show that nutritional devices are frequently used by CdLS patients, also if the majority of them (93.1%) succeed with time in achieving a normal oral nutrition. Finally, the need, the type of device used and the duration of NGT or/plus PEG can be considered a further sign of worse prognosis of the disease itself.

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.

CyclinD1 Down-Regulation and Increased Apoptosis Are Common Features of Cohesinopathies.

Genetic variants within components of the cohesin complex (NIPBL, SMC1A, SMC3, RAD21, PDS5, ESCO2, HDAC8) are believed to be responsible for a spectrum of human syndromes known as "cohesinopathies" that includes Cornelia de Lange Syndrome (CdLS). CdLS is a multiple malformation syndrome affecting almost any organ and causing severe developmental delay. Cohesinopathies seem to be caused by dysregulation of specific developmental pathways downstream of mutations in cohesin components. However, it is still unclear how mutations in different components of the cohesin complex affect the output of gene regulation. In this study, zebrafish embryos and SMC1A-mutated patient-derived fibroblasts were used to analyze abnormalities induced by SMC1A loss of function. We show that the knockdown of smc1a in zebrafish impairs neural development, increases apoptosis, and specifically down-regulates Ccnd1 levels. The same down-regulation of cohesin targets is observed in SMC1A-mutated patient fibroblasts. Previously, we have demonstrated that haploinsufficiency of NIPBL produces similar effects in zebrafish and in patients fibroblasts indicating a possible common feature for neurological defects and mental retardation in cohesinopathies. Interestingly, expression analysis of Smc1a and Nipbl in developing mouse embryos reveals a specific pattern in the hindbrain, suggesting a role for cohesins in neural development in vertebrates.

A new prognostic index of severity of intellectual disabilities in Cornelia de Lange syndrome.

Cornelia de Lange syndrome is a well-known multiple congenital anomalies/intellectual disability syndrome with genetic heterogeneity and wide clinical variability, regarding the severity of both the intellectual disabilities and the physical features, not completely explained by the genotype-phenotype correlations known to date. The aim of the study was the identification of prognostic features, ascertainable precociously in the patient's life, of a better intellectual outcome and the development of a new prognostic index of severity of intellectual disability in CdLS patients. In 66 italian CdLS patients aged 8 years or more, we evaluated the association of the degree of intellectual disability with various clinical parameters ascertainable before 6 months of life and with the molecular data by the application of cumulative regression logistic model. Based on these results and on the previously known genotype-phenotype correlations, we selected seven parameters to be used in a multivariate cumulative regression logistic model to develop a prognostic index of severity of intellectual disability. The probability of a mild ID increases with the reducing final score less than two, the probability of a severe ID increases with the increasing final score more than three. This prognostic index allows to define, precociously in the life of a baby, the probability of a better or worse intellectual outcome in CdLS patients. © 2016 Wiley Periodicals, Inc.

Sedation and general anesthesia for patients with Cornelia De Lange syndrome: A case series.

Cornelia De Lange syndrome (CdLS) is a rare congenital disease characterized by typical facial dysmorphism, developmental disability, and limb deficiency defects. Various congenital malformations and medical complications have been described with gastroesophageal reflux as the major one. CdLS patients often require multiple high-risk anesthetic procedures. At San Gerardo Hospital (Monza, Italy) the management of CdLS patients is routinely organized through a standard protocol and a dedicated pediatric anesthesia team has been implemented. We report on a retrospective descriptive analysis of the anesthetic records of the CdLS patients admitted to San Gerardo Hospital from January 2010 to December 2015. We retrieved: demographics, genetic profiles, type of procedures, anesthetic approaches, anesthetics usage and complications. Data are reported as median (interquartile range) values. Twenty-seven patients (11 female), with age 12 (7-15) years old, weight 24 (14-35) kg, and severity score of 25 (18-32) were included. NIBPL mutations were the most frequently represented. We analyzed 58 procedures (30 esophagogastroduodenoscopies, 8 evoked auditory potential tests, 5 radiodiagnostics, 5 catheters positioning, 4 bronchoscopies) managed by sedation (36) and general anesthesia (6). Each patient underwent one (1-2) anesthetic procedure. Propofol (59%), sevoflurane (31%), fentanyl (24%), and ketamine (10%) were used. Three out of six endotracheal intubations were difficult. The only documented intraoperative complications were three episodes of desaturation (oxygen saturation <90%) occurring during sedations and were managed without the need for an invasive control of the airways. Implementation of a specific management protocol and a dedicated allowed to provide anesthesia to CdLS patients without the occurrence of major complications. © 2016 Wiley Periodicals, Inc.

Adolescents and adults affected by Cornelia de Lange syndrome: A report of 73 Italian patients.

Cornelia de Lange syndrome (CdLS) is a rare genetic condition related to mutation of various cohesion complex related genes. Its natural history is quite well characterized as regard pediatric age. Relatively little information is available regarding the evolution of the disease in young-adult age. In medical literature, only one specific study has been published on this topic. We report on our experience on 73 Italian CdLS patients (40 males and 33 females) with and age range from 15 to 49 years. Our results confirm the previous study indicating that gastroesophageal reflux disease (GERD) is the main medical problem of these patients in childhood and young-adult age. Other medical features that should be considered in the medical follow-up are tendency to overweight/frank obesity, constipation, discrepancy of limbs' length, epilepsy, hearing, and visual problems. Behavioral problems are particularly frequent as well. For this reason, every source of hidden pain should be actively searched for in evaluating a patient showing such a disorder. Finally, recommendations for medical follow-up in adult age are discussed. © 2016 Wiley Periodicals, Inc.