Multidisciplinary follow-up in a patient with Morgagni hernia leads to diagnosis of Marfan syndrome.

BACKGROUND: congenital diaphragmatic hernia (CDH) is a birth defect occurring in isolated or syndromic (chromosomal or monogenic) conditions. The diaphragmatic defect can be the most common one: left-sided posterolateral, named Bochdalek hernia; or it can be an anterior-retrosternal defect, named Morgagni hernia. Marfan syndrome (MFS) is a rare autosomal dominant inherited condition that affects connective tissue, caused by mutations in fibrillin-1 gene on chromosome 15. To date various types of diaphragmatic defects (about 30 types) have been reported in association with MFS, but they are heterogeneous, including CDH and paraesophageal hernia. CASE PRESENTATION: We describe the case of a child incidentally diagnosed with Morgagni hernia through a chest X-ray performed due to recurrent respiratory tract infections. Since the diagnosis of CDH, the patient underwent a clinical multidisciplinary follow-up leading to the diagnosis of MFS in accordance with revised Ghent Criteria: the child had typical clinical features and a novel heterozygous de novo single-base deletion in exon 26 of the FBN1 gene, identified by Whole-Exome Sequencing. MFS diagnosis permitted to look for cardiovascular complications and treat them, though asymptomatic, in order to prevent major cardiovascular life-threatening events. CONCLUSION: Our case shows the importance of a long-term and multidisciplinary follow-up in all children with diagnosis of CDH.

Maternal input to 24-month-old children with sex chromosome trisomies.

BACKGROUND: Maternal input plays an important role in influencing linguistic development during the first years of life, and it is evident that mothers adapt their language according to their child's characteristics. Recently, it was demonstrated that maternal input addressed to children with sex chromosome trisomies (SCTs) at 8 months of age is prosodically and functionally different from that addressed to typically developing (TD) peers. AIMS: The study aimed at analysing maternal input at 24 months when the presence of a language delay could be more evident than during the preverbal stage. We were interested in examining if maternal input was influenced by a diagnosis of SCT (by comparing children with SCT and TD children) or by children's linguistic level (by comparing children with weak lexical ability versus children with typical lexical ability regardless of the presence of genetic diagnosis). METHODS AND PROCEDURES: Forty-four mother-child dyads in which the children had an SCT and 20 mother-child dyads in which the children were TD participated in the study. Of these 64 dyads, 23 children (21 with SCTs and two TD children) formed the group of children with weak lexical ability (children with a vocabulary size lower than 50 words at 24 months). Maternal utterances were collected during one video-recorded play session and were then coded considering both the linguistic and functional features of the input. OUTCOMES AND RESULTS: The results showed that the input addressed to 24-month-old children with SCTs is as rich and complex as that addressed to TD peers. Moreover, no significant differences in the functions expressed by maternal input were found (all ps > 0.05). Comparing the children with weak lexical ability and the children with typical lexical ability in our sample, having a poor vocabulary at 24 months of age showed a significant influence on the maternal input features: the input addressed to children with weak lexical ability was characterised by a higher presence of attention getters (U = 217.00, p = 0.007) and a lower proportion of questions (U = 236.00, p = 0.017) than that of mothers of typically-talking children. CONCLUSIONS AND IMPLICATIONS: At 24 months of age, it seems that the presence of a language delay and not belonging to the clinical group of children with SCTs influences the functional characteristics of the maternal input. It is important to support the parents of children with SCTs during the communication process and later during their child's development, leading them to observe their children's manifested skills rather than looking for possible predicted difficulties. WHAT THIS PAPER ADDS: What is already known on the subject Studies in the literature demonstrated how mothers can generally adapt their input to their child's characteristics. To our knowledge, only two recent studies analysed the maternal input addressed to children with SCT at 8 months of age, highlighting significant differences. What this paper adds to existing knowledge The maternal input addressed to children with SCT at 24 months of age is not different from that addressed to TD children. At 24 months of age, the mothers adapt their input to the verbal competence shown by their child (weak lexical ability versus typically-talking), while belonging to the clinical group does not show an influence. What are the potential or actual clinical implications of this work? All the participants of the present study received prenatal diagnosis disclosure by an expert team of professionals, and they were all involved in a longitudinal study aimed at monitoring the children's development and supporting their parents. These results show that giving clear and complete information about possible development paths to parents of children with SCTs during diagnosis disclosure is crucial. Moreover, supporting the parents during the communication process and later during their child's development is fundamental, leading them to observe their children's manifested skills rather than looking for possible predicted difficulties.

The effect of a priming-based training on the production of object clitic pronouns in Italian speaking children with DLD.

Children with developmental language disorders (DLD) have impaired morphosyntactic abilities despite age-appropriate nonverbal cognitive abilities and no hearing disorders or brain injury. The persistent omission of third-person object clitic pronouns (3DO clitics) has been proven to be a clinical marker of developmental language disorders (DLD) for both preschool and school-aged Italian-speaking children. According to the model of 3DO clitic derivation recently brought to attention, 3DO clitic omission is a morphosyntactic matter and, therefore, we argue that the production of 3DO clitics can be enhanced through morphosyntactic priming in children with DLD. To corroborate this hypothesis, we administered a 3DO clitic training based on a morphosyntactic priming paradigm to 23 typically developing (TD) children and 11 children with DLD. Results show that their 3DO clitic production is enhanced after the training and that these effects are persistent in time. Our results suggest that a priming-based training can concretely help children with DLD in their language development.

Chung-Jansen syndrome can mimic Cornelia de Lange syndrome: Another player among chromatinopathies?

Cornelia de Lange syndrome (CdLS) is a rare multisystem congenital neurodevelopmental disorder (NDD) characterized by distinctive facial anomalies, short stature, developmental delay, hirsutism, gastrointestinal abnormalities and upper limb reduction defects. CdLS syndrome is associated with causative variants in genes encoding for the cohesin complex, a cellular machinery involved in chromatid pairing, DNA repair and gene-expression regulation. In this report, we describe a familial case of a syndromic presentation in a 4-year-old patient (P1) and in his mother (P2). Trio-based Whole Exome Sequencing (WES) performed on P1 was first negative. Since his phenotypic evolution during the follow-up was reminiscent of the CdLS spectrum, a reanalysis of WES data, focused on CdLS-related genes, was requested. Although no alterations in those genes was detected, we identified the likely pathogenetic variant c.40G > A (p.Glu14Lys) in the PHIP gene, in the meanwhile associated with Chung-Jansen syndrome. Reverse phenotyping carried out in both patients confirmed the molecular diagnosis. CHUJANS belongs to NDDs, featuring developmental delay, mild-to-moderate intellectual disability, behavioral problems, obesity and facial dysmorphisms. Moreover, as here described, CHUJANS shows a significant overlap with the CdLS spectrum, with specific regard to facial gestalt. On the basis of our findings, we suggest to include PHIP among genes routinely analyzed in patients belonging to the CdLS spectrum.

Speech Sound Development in 18-Month-Old Children With Sex Chromosome Trisomies.

PURPOSE: This study aimed to describe speech sound development in a group of 18-month-old children with sex chromosome trisomies (SCTs), compared with a group of typically developing (TD) peers. Concurrent and longitudinal relationships between speech sound abilities and lexical development were examined. METHOD: A group of 76 children aged 18 months, 38 children prenatally diagnosed with SCTs (12 with XXY, 12 with XYY, and 14 with XXX) and 38 TD children, participated in the study. From video recordings of semistructured naturalistic parent-child play sessions, quantitative and qualitative measures of speech sound development were collected (e.g., the number of consonants, type and place of articulation, and syllable structures used), and group differences were observed. The relationships between the number of consonants produced and vocabulary size at 18 and 24 months were assessed. RESULTS: At 18 months, children with SCTs used a significantly lower number of consonants than TD children. Qualitatively, children with SCTs used significantly fewer articulatory complex consonants (fricative/affricates) and a more restricted inventory of syllable structures. The number of consonants used was significantly correlated with lexical development at 18 months. Moreover, in the SCTs group (but not in the TD group), the children with lower speech sound development at 18 months showed a significantly smaller vocabulary growth between 18 and 24 months than those with higher speech-sound development. CONCLUSIONS: Toddlers with SCTs showed a significantly delayed speech sound development pattern rather than an atypical one. Children with SCTs with low speech sound development also showed lower vocabulary growth between 18 and 24 months of age. These results can be clinically relevant for follow-up and treatment planning for children with SCTs.

The developmental trajectories of the behavioral phenotype and neuropsychiatric functioning in Cornelia de Lange and Rubinstein Taybi syndromes: A longitudinal study.

Several changes in the behavioral phenotype arise with the growth of children affected by Cornelia de Lange Syndrome (CdLS) and Rubinstein-Taybi Syndrome (RSTS). However, previous research relied on a cross-sectional study design turning into age-related comparisons of different syndromic cohorts to explore age-dependent changes. We aim to outline the variating pathways of the neuropsychiatric functioning across the lifespan in CdLS and RSTS, through the setting up of a longitudinal study design. The sample included 14 patients with CdLS and 15 with RSTS. The assessments were carried out in two different timepoints. Our findings highlight that the cognitive profile of CdLS is subjected to a worsening trend with decreasing Intellectual Quotient (IQ) scores from T0 to T1, whereas RSTS shows a stable IQ over time. Patients affected by RSTS show greater improvements compared to CdLS in communication, daily living skills, social abilities, and motor skills across the lifespan. Both syndromes report an upward trend in behavioral and emotional difficulties even if CdLS exhibit a significant and major deterioration compared to individuals with RSTS. Being aware of the early dysfunctional patterns which might pave the way for later neuropsychiatric impairments is the first step for planning preventive interventions.

Short report. Narrative competence in Italian preschool children with sex chromosome trisomies.

BACKGROUND: The neuropsychological profile of children with sex chromosome trisomies [SCTs] is frequently characterised by delays and impairments in language development. However, no studies so far have specifically investigated their narrative competence. AIMS: The aim of the study was to analyse the oral narrative competence of preschool children with SCTs due to the importance of this skill for language development and learning abilities. METHODS AND PROCEDURES: Participants were 34 Italian children with SCTs one-to-one matched by age and sex to typically developing [TD] children. A storytelling task, the Narrative Competence Task, was used to assess the macrostructural and microstructural features of the children's narratives. OUTCOMES AND RESULTS: Children with SCTs showed significantly lower scores than TD peers in all the narrative indices considered, except for mental state lexicon and story length in words. CONCLUSIONS AND IMPLICATIONS: The problems found in narrative competence confirmed the existence of difficulties in the language development of children with SCTs. Narrative difficulties could affect these children's future learning skills and academic achievements.

Case Report: Effect of Targeted Therapy With Carbamazepine in KCNQ2 Neonatal Epilepsy.

We present a family case of neonatal-onset KCNQ2-related epilepsy due to a novel intronic mutation. Three members of an Italian family (father and offspring) presented with neonatal-onset asymmetric tonic and clonic seizures with peculiar video-electroencephalography and aEEG features referring to sequential seizures. The father and the first son underwent standard of care treatments in line with current neonatal intensive care unit protocols, with a prolonged hospitalization before reaching full seizure control with carbamazepine. After the experience acquired with her family and the latest advances in the literature, the younger daughter was directly treated with carbamazepine, obtaining rapid seizure control and short hospitalization. They all had normal development. Carbamazepine is rarely administered as a first-line option in neonatal seizures. Recent evidence suggests that neonatal intensive care unit protocols should implement a trial with sodium channel blockers such as carbamazepine as first-option anti-seizure medication and a fast access to genetic testing in neonates with sequential seizures without structural brain injury or acute causes. Moreover, we report and discuss the laboratory studies performed on a novel causative intronic mutation in KCNQ2 (c.1525+5 G>A in IVS13), since pathogenicity may be difficult to prove for intronic variants.

Age-related hallmarks of psychopathology in Cornelia de Lange and Rubinstein-Taybi syndromes.

BACKGROUND AND AIM: There is mounting evidence highlighting that Cornelia de Lange Syndrome (CdLS) and Rubinstein-Taybi Syndrome's (RSTS) behavioral phenotypes are not stable over individual developmental trajectories and that several psychiatric disorders might arise with age. Our study aims to examine the specific hallmarks of psychopathology and behavioral phenotypes in four different age ranges: infancy and toddlerhood, early childhood, middle childhood, and adolescence, in both genetic syndromes. METHOD: The sample included 44 patients with CdLS (48% boys, age = 6.67 ± 4.36) and 31 with RSTS (48% boys, age = 6.89 ± 4.58) recruited through follow-ups. Cognitive, behavioral, and autism assessments were carried out with Griffith's scales or the Leiter-R, the Child Behavior Checklist, and the Child Autism Rating Scales 2. Multiple ANOVA 2 × 4 were run to outline behavioral phenotypic age-related syndromic markers and ANCOVA to value the weight of IQ and ASD-related traits on the psychopathological outcome. RESULTS: Findings showed that anxiety is a crucial phenotypic hallmark, independent of IQ but associated with autistic traits, that increases from infancy to adolescence in both CdLS and RSTS. CONCLUSION AND IMPLICATIONS: Being aware of the developmental challenges that growing children are called to face is essential for drawing up proper standards of assessment turning into target age-related interventions, ensuring these patients personalized healthcare and improvement in life quality.

Language Development in the Second Year of Life: The Case of Children with Sex Chromosome Trisomies Diagnosed before Birth.

Many individual factors, such as early communicative skills, could play a role in explaining later linguistic outcomes. The detection of predictive variables is fundamental to identifying early the children who need intervention. The present study focuses on children with sex chromosome trisomies (SCTs), genetic conditions with an increased risk of developing language delays or impairments. The aims are to analyse their communicative skills at 18 months of age, and identify significant predictors of their later vocabulary size. Participants were 76 18-month-old children (38 with SCTs, and 38 typically-developing (TD) children). Their communicative skills were assessed during a parent-child play session, and parents filled in a report on their vocabulary development at 18 and 24 months. Children with SCTs showed significantly poorer linguistic skills at 18 months in both preverbal (babbling and gestures) and verbal abilities. A high percentage (nearly 70%) of toddlers with SCTs were late-talking children at 24 months, and those toddlers showed a lower frequency of babbling utterances at 18 months. Early lexical skills, children's developmental quotient, and being part of the group of toddlers with SCTs were significant predictors of children's vocabulary size six months later. These variables should be considered when assessing the linguistic competence of a child with SCTs to detect possible early risk factors of future language impairment.

Language Development in Sex Chromosome Trisomies: Developmental Profiles at 2 and 4 Years of Age, and Predictive Measures.

PURPOSE: Describing language development in children with sex chromosome trisomies (SCT) and testing the predictive value of early language measures on later outcomes. METHOD: Thirteen children with SCT were followed longitudinally. Their developmental profile was assessed, with particular attention to language, at 2 and 4 years. The predictive value of direct (spontaneous speech analysis) and indirect (communicative development inventory) language measures at 2 on performances at 4 was tested. RESULTS: Language performances at both ages were lower than non-verbal development. At 2, more than 50% of the group produced less than 50 words. At 4, impaired performances were observed in speech sound development and expressive morpho-syntax. Direct measures of Pre-syntactic development predicted later global language outcomes and Sentence Repetition. The number of consonants used at 2 was significantly related to Nonword Repetition at 4. CONCLUSIONS: The study highlights the importance of early detection and careful follow-up for children with SCT.

Neuropsychiatric Functioning in CDLS: A Detailed Phenotype and Genotype Correlation.

Behavioural phenotype and autism-related traits of 38 patients affected by Cornelia de Lange syndrome (CdLS) were assessed using a specific neuropsychiatric protocol. Subsequently,we search for possible genotype-phenotype correlations comparing individuals with NIPBL variants and patients with negative molecular results. Firstly results showed a higher percentage of subjects with normal intellectual quotient (IQ) and borderline IQ; adaptive skills were lower than expected for age in all participants. 39.5% of the sample presented with autism spectrum disorder (ASD), NIPBL mutated individuals demonstrated a worse trend in comparison with the clinical diagnosis group. non-truncating individuals displayed no ASD and better communication abilities than truncating individuals. Findings increase our awareness of the strengths and weaknesses points in CdLS individuals.

Children's Behavior and Maternal Parenting Stress in Young Children With Sex Chromosome Trisomies.

OBJECTIVE: Children and adolescents with sex chromosome trisomies (SCTs) usually show a higher frequency of behavioral problems than typically developing (TD) children. However, little is known about the presence of behavioral issues in toddlers with SCT. This study aimed at investigating their behavioral profile in the second year of life and its impact on maternal stress. METHOD: Participants were 87 children ranging in age from 18 to 26 months: 63 children with SCTs (all diagnosed prenatally) and 24 TD children. Their psychomotor and language development and their behavioral profile were assessed. In addition, the level of maternal parenting stress was evaluated. RESULTS: Both psychomotor and language development were significantly lower in children with SCTs than in TD children. Conversely, no significantly greater behavioral problems emerged in children with SCTs. However, a significantly higher level of parenting stress related to a dysfunctional interaction with the child emerged in the mothers of children with SCTs. In this population, maternal stress seemed positively related to their children's emotional problems and pervasive disorders and negatively related to their children's psychomotor and linguistic competence. CONCLUSION: Although no significant behavioral issues emerged in the second year of life, the relationships found between children's behavioral profiles and maternal parenting stress highlight the importance of prenatal counseling and support groups for parents of children with SCTs. This might help them recognize the first signs of behavioral problems and become aware of their influence on parenting stress.

Behavioral markers of social anxiety in Cornelia de Lange Syndrome: A brief systematic review.

BACKGROUND: There is evidence that social impairments in Cornelia de Lange Syndrome (CdLS) differ from those observed in idiopathic autism as they are characterized mainly by social anxiety. However, the knowledge of the fundamental features of social anxiety symptoms in this target population is limited. This brief systematic review aims to investigate the relationship between social anxiety and CdLS through multiple cross-sectional comparisons. METHODS: PRISMA-P guidelines were followed, and the literature research was conducted in Pubmed, EBSCOhost, Google Scholar, and ScienceDirect using "Cornelia de Lange Syndrome" or "CdLS" and "social anxiety" as search terms. RESULTS: Six articles met the eligibility criteria. Results show that heightened levels of social anxiety in CdLS individuals occur before and after the social engagement and are mediated by both the nature of the social demand and the familiarity of the examiner they interact with. LIMITATIONS: The interpretation of results is limited by the wide heterogeneity of patients' age and sample size across the reviewed studies, and by the absence of a unique observational procedure to detect behaviors indicative of social anxiety in syndromic individuals. CONCLUSIONS: These findings have considerable clinical implications for intervention planning which might be generalized to all people with intellectual disability linked to a genetic syndrome.

Irony Comprehension in Children With Cochlear Implants: The Role of Language Competence, Theory of Mind, and Prosody Recognition.

Purpose Aims of this research were (a) to investigate higher order linguistic and cognitive skills of Italian children with cochlear implants (CIs); (b) to correlate them with the comprehension of irony, which has never been systematically studied in this population; and (c) to identify the factors that facilitate the development of this competence. Method We tested 28 Italian children with CI (mean chronological age = 101 [SD = 25.60] months, age range: 60-144 months), and two control groups of normal-hearing (NH) peers matched for chronological age and for hearing age, on a series of tests assessing their cognitive abilities (nonverbal intelligence and theory of mind), linguistic skills (morphosyntax and prosody recognition), and irony comprehension. Results Despite having grammatical abilities in line with the group of NH children matched for hearing age, children with CI lag behind both groups of NH peers on the recognition of emotions through prosody and on the comprehension of ironic stories, even if these two abilities were not related. Conclusions This is the first study that targeted irony comprehension in children with CI, and we found that this competence, which is crucial for maintaining good social relationships with peers, is impaired in this population. In line with other studies, we found a correlation between this ability and advanced theory of mind skills, but at the same time, a deeper investigation is needed, to account for the high variability of performance in children with CI.

Histone Deacetylase Inhibitors Ameliorate Morphological Defects and Hypoexcitability of iPSC-Neurons from Rubinstein-Taybi Patients.

Rubinstein-Taybi syndrome (RSTS) is a rare neurodevelopmental disorder caused by mutations in CREBBP or EP300 genes encoding CBP/p300 lysine acetyltransferases. We investigated the efficacy of the histone deacetylase inhibitor (HDACi) Trichostatin A (TSA) in ameliorating morphological abnormalities of iPSC-derived young neurons from P149 and P34 CREBBP-mutated patients and hypoexcitability of mature neurons from P149. Neural progenitors from both patients' iPSC lines were cultured one week with TSA 20 nM and, only P149, for 6 weeks with TSA 0.2 nM, in parallel to neural progenitors from controls. Immunofluorescence of MAP2/TUJ1 positive cells using the Skeletonize Image J plugin evidenced that TSA partially rescued reduced nuclear area, and decreased branch length and abnormal end points number of both 45 days patients' neurons, but did not influence the diminished percentage of their neurons with respect to controls. Patch clamp recordings of TSA-treated post-mitotic P149 neurons showed complete/partial rescue of sodium/potassium currents and significant enhancement of neuron excitability compared to untreated replicas. Correction of abnormalities of P149 young neurons was also affected by valproic acid 1 mM for 72 h, with some variation, with respect to TSA, on the morphological parameter. These findings hold promise for development of an epigenetic therapy to attenuate RSTS patients cognitive impairment.

Lithium as a possible therapeutic strategy for Cornelia de Lange syndrome.

Cornelia de Lange Syndrome (CdLS) is a rare developmental disorder affecting a multitude of organs including the central nervous system, inducing a variable neurodevelopmental delay. CdLS malformations derive from the deregulation of developmental pathways, inclusive of the canonical WNT pathway. We have evaluated MRI anomalies and behavioral and neurological clinical manifestations in CdLS patients. Importantly, we observed in our cohort a significant association between behavioral disturbance and structural abnormalities in brain structures of hindbrain embryonic origin. Considering the cumulative evidence on the cohesin-WNT-hindbrain shaping cascade, we have explored possible ameliorative effects of chemical activation of the canonical WNT pathway with lithium chloride in different models: (I) Drosophila melanogaster CdLS model showing a significant rescue of mushroom bodies morphology in the adult flies; (II) mouse neural stem cells restoring physiological levels in proliferation rate and differentiation capabilities toward the neuronal lineage; (III) lymphoblastoid cell lines from CdLS patients and healthy donors restoring cellular proliferation rate and inducing the expression of CyclinD1. This work supports a role for WNT-pathway regulation of CdLS brain and behavioral abnormalities and a consistent phenotype rescue by lithium in experimental models.

Biallelic MADD variants cause a phenotypic spectrum ranging from developmental delay to a multisystem disorder.

In pleiotropic diseases, multiple organ systems are affected causing a variety of clinical manifestations. Here, we report a pleiotropic disorder with a unique constellation of neurological, endocrine, exocrine, and haematological findings that is caused by biallelic MADD variants. MADD, the mitogen-activated protein kinase (MAPK) activating death domain protein, regulates various cellular functions, such as vesicle trafficking, activity of the Rab3 and Rab27 small GTPases, tumour necrosis factor-α (TNF-α)-induced signalling and prevention of cell death. Through national collaboration and GeneMatcher, we collected 23 patients with 21 different pathogenic MADD variants identified by next-generation sequencing. We clinically evaluated the series of patients and categorized the phenotypes in two groups. Group 1 consists of 14 patients with severe developmental delay, endo- and exocrine dysfunction, impairment of the sensory and autonomic nervous system, and haematological anomalies. The clinical course during the first years of life can be potentially fatal. The nine patients in Group 2 have a predominant neurological phenotype comprising mild-to-severe developmental delay, hypotonia, speech impairment, and seizures. Analysis of mRNA revealed multiple aberrant MADD transcripts in two patient-derived fibroblast cell lines. Relative quantification of MADD mRNA and protein in fibroblasts of five affected individuals showed a drastic reduction or loss of MADD. We conducted functional tests to determine the impact of the variants on different pathways. Treatment of patient-derived fibroblasts with TNF-α resulted in reduced phosphorylation of the extracellular signal-regulated kinases 1 and 2, enhanced activation of the pro-apoptotic enzymes caspase-3 and -7 and increased apoptosis compared to control cells. We analysed internalization of epidermal growth factor in patient cells and identified a defect in endocytosis of epidermal growth factor. We conclude that MADD deficiency underlies multiple cellular defects that can be attributed to alterations of TNF-α-dependent signalling pathways and defects in vesicular trafficking. Our data highlight the multifaceted role of MADD as a signalling molecule in different organs and reveal its physiological role in regulating the function of the sensory and autonomic nervous system and endo- and exocrine glands.

Olfactory Malformations in Mendelian Disorders of the Epigenetic Machinery.

Usually overlooked by physicians, olfactory abnormalities are not uncommon. Olfactory malformations have recently been reported in an emerging group of genetic disorders called Mendelian Disorders of the Epigenetic Machinery (MDEM). This study aims to determine the prevalence of olfactory malformations in a heterogeneous group of subjects with MDEM. We reviewed the clinical data of 35 patients, 20 females and 15 males, with a mean age of 9.52 years (SD 4.99). All patients had a MDEM and an already available high-resolution brain MRI scan. Two experienced neuroradiologists reviewed the MR images, noting abnormalities and classifying olfactory malformations. Main findings included Corpus Callosum, Cerebellar vermis, and olfactory defects. The latter were found in 11/35 cases (31.4%), of which 7/11 had Rubinstein-Taybi syndrome (RSTS), 2/11 had CHARGE syndrome, 1/11 had Kleefstra syndrome (KLFS), and 1/11 had Weaver syndrome (WVS). The irregularities mainly concerned the olfactory bulbs and were bilateral in 9/11 patients. With over 30% of our sample having an olfactory malformation, this study reveals a possible new diagnostic marker for MDEM and links the epigenetic machinery to the development of the olfactory bulbs.

(Epi)genetic profiling of extraembryonic and postnatal tissues from female monozygotic twins discordant for Beckwith-Wiedemann syndrome.

BACKGROUND: Beckwith-Wiedemann syndrome (BWS) is an overgrowth disorder caused by defects at the 11p15.5 imprinted region. Many cases of female monozygotic (MZ) twins discordant for BWS have been reported, but no definitive conclusions have been drawn regarding the link between epigenetic defects, twinning process, and gender. Here, we report a comprehensive characterization and follow-up of female MZ twins discordant for BWS. METHODS: Methylation pattern at 11p15.5 and multilocus methylation disturbance (MLID) profiling were performed by pyrosequencing and MassARRAY in placental/umbilical cord samples and postnatal tissues. Whole-exome sequencing was carried out to identify MLID causative mutations. X-chromosome inactivation (XCI) was determined by HUMARA test. RESULTS: Both twins share KCNQ1OT1:TSS-DMR loss of methylation (LOM) and MLID in blood and the epigenetic defect remained stable in the healthy twin over time. KCNQ1OT1:TSS-DMRLOM was nonhomogeneously distributed in placental samples and the twins showed the same severely skewed XCI pattern. No MLID-causative mutations were identified. CONCLUSION: This is the first report on BWS-discordant twins with methylation analyses extended to extraembryonic tissues. The results suggest that caution is required when attempting prenatal diagnosis in similar cases. Although the causative mechanism underlying LOM remains undiscovered, the XCI pattern and mosaic LOM suggest that both twinning and LOM/MLID occurred after XCI commitment.