Mismatch Repair Deficiency in Biliary Tract Cancer: Prognostic Implications and Correlation with Histology.

INTRODUCTION: Mismatch repair (MMR) deficiency represents a biomarker and therapeutic target in various neoplasms, but its role in biliary tract cancers (BTCs) remains misunderstood. METHODS: MMR status was retrospectively assessed using immunohistochemistry in 163-BTCs patients. We identified MMR proficiency (pMMR)/deficiency (dMMR) according to the loss of MMR proteins (MLH1, PMS2, MSH2, MSH6). The primary objective of the study was to assess the incidence of dMMR in BTCs; the secondary purpose was to explore its association with prognosis and clinical features. RESULTS: dMMR was recorded in 9 patients, and it was strongly associated with mucinous histology (p < 0.01). Regarding the prognostic effect, in 122-radically resected patients, disease-free survival (DFS) resulted significantly shorter in dMMR patients compared to pMMR patients (10.7 vs. 31.3 months, p = 0.025) and so did nodal status (48.2 vs. 15.3 months in N0 vs. N+) (p < 0.01). Moreover, dMMR confirmed its prognostic role in terms of DFS at multivariate analysis (p = 0.03), together with nodal status (p = 0.01), and resection margin (p = 0.03). In 103 M+ patients (encompassing 41 metastatic de novo and 62 recurred after surgery patients) there were not differences between dMMR and pMMR regarding survival analyses. CONCLUSIONS: dMMR status is strongly correlated with mucinous histology and represents an independent prognostic factor in terms of disease relapse in patients with resected BTC. IMPLICATIONS FOR PRACTICE: MMR may play an independent role in promoting an aggressive behaviour in patients with radically resected BTC. These results could be useful in improving the selection of patients after resection and, above all, should justify the evaluation of MMR status as a therapeutic target in BTC, especially in patients with atypical histology.

A new gene for autosomal dominant facial palsy/migraine identified in a family by whole exome sequencing.

BACKGROUND: Facial palsy manifests as unilateral or bilateral weakness and inability to move some of the facial muscles. The aetiology may be different including idiopathic, trauma, infections or brain tumours or it can be associated with chronic neurological diseases. For instance, in recurrent migraine, an increased risk of idiopathic facial palsy (often unilateral) has been observed. Migraine is a neurovascular disorder characterized by mild to severe intensity of headaches, often associated with neuro-ophthalmological symptoms. METHODS: A family is reported where five members were affected by facial palsy associated with other clinical features including migraine, diplopia, facial swelling, eye conjunctivitis following a vertical transmission. Whole exome sequencing was performed in three members (two affected and one healthy) in order to identify potential variants causative of their phenotype. RESULTS: A missense variant c.304G>A was found leading to the p.(Ala102Thr) substitution in the TRPM8 gene, previously related to migraine by genome wide association studies. This variant was classified as deleterious by several predictor tools, and the mutant residue was predicted to alter the protein structure in terms of flexibility and interactions with the surrounding residues. CONCLUSION: These findings suggest that TRPM8 could be a new causative gene further linking migraine and recurrent facial palsy.

Dabrafenib-trametinib in BRAF V600-mutated non-small-cell lung cancer: a single center real world experience.

Aim: We retrospectively evaluated the effect of dabrafenib/trametinib combination in patients with BRAF-mutated non-small-cell lung cancer (NSCLC) treated in a single center from 2017 to 2022. Patients: The response and safety data of 42 patients (27 treated in first-line and 15 as second/subsequent lines) were analyzed. Results: The objective response was 73.8%, with no differences between patients undergoing first- or second-line. A longer, statistically significant median progression-free survival (PFS) was observed in patients receiving the combination in first-line vs those in the second/subsequent lines (19.9 months [95% CI: 19.7-20] vs 13.1 months [95% CI: 8.6-17.6], respectively; p = 0.012). The median overall survival (OS) was 29.9 months (95% CI: 14.1-45.7) for patients treated with the combination in first-line and 22.4 months (95% CI: 14.6-30.2) for those treated in subsequent lines. The combination was well tolerated. Conclusion: We confirm the efficacy of dabrafenib/trametinib in BRAF-V600-mutated NSCLC.

[Box: see text].

Mosaic genome-wide paternal uniparental disomy after discordant results from primary fetal samples and cultured cells.

Mosaic genome-wide paternal uniparental disomy (GWpUPD) is a rare condition in which two euploid cell lines coexist in the same individual, one with biparental content and one with genome-wide paternal isodisomy. We report a complex prenatal diagnosis with discordant results from cultured and uncultured samples. A pregnant woman was referred for placental mesenchymal dysplasia and fetal omphalocele. Karyotype, array-CGH and Beckwith-Wiedemann Syndrome (BWS) testing (methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) of 11p15) performed on amniocytes were negative. After intrauterine fetal demise, the clinical suspicion persisted and BWS MS-MLPA was repeated on cultured cells from umbilical cord and amniotic fluid, revealing a mosaicism for KvH19 hypermethylation/KCNQ1OT1:TSS:DMR hypomethylation. These results, along with microsatellite analysis of the BWS region, were consistent with mosaic paternal 11p15 isodisomy. A concurrent maternal contamination exclusion test, analyzing polymorphic microsatellite markers on multiple chromosomes, showed an imbalance in favor of paternal alleles at all examined loci on cultured amniocytes and umbilical cord samples. This led to suspicion of mosaic GWpUPD, later confirmed by SNP-array, identifying a mosaic genome-wide paternal isodisomy affecting 60% of fetal cells. The assessment of mosaic GWpUPD requires multiple approaches beyond the current established diagnostic processes, also entertaining possible low-rate mosaicism. Clinical acumen and an integrated testing approach are the key to a successful diagnosis.

A novel complex genomic rearrangement affecting the KCNJ2 regulatory region causes a variant of Cooks syndrome.

Cooks syndrome (CS) is an ultrarare limb malformation due to in tandem microduplications involving KCNJ2 and extending to the 5' regulatory element of SOX9. To date, six CS families were resolved at the molecular level. Subsequent studies explored the evolutionary and pathological complexities of the SOX9-KCNJ2/Sox9-Kcnj2 locus, and suggested a key role for the formation of novel topologically associating domain (TAD) by inter-TAD duplications in causing CS. Here, we report a unique case of CS associated with a de novo 1;17 translocation affecting the KCNJ2 locus. On chromosome 17, the breakpoint mapped between KCNJ16 and KCNJ2, and combined with a ~ 5 kb deletion in the 5' of KCNJ2. Based on available capture Hi-C data, the breakpoint on chromosome 17 separated KCNJ2 from a putative enhancer. Gene expression analysis demonstrated downregulation of KCNJ2 in both patient's blood cells and cultured skin fibroblasts. Our findings suggest that a complex rearrangement falling in the 5' of KCNJ2 may mimic the developmental consequences of in tandem duplications affecting the SOX9-KCNJ2/Sox9-Kcnj2 locus. This finding adds weight to the notion of an intricate role of gene regulatory regions and, presumably, the related three-dimensional chromatin structure in normal and abnormal human morphology.

Koolen-de Vries syndrome in a 63-year-old woman: Report of the oldest patient and a review of the adult phenotype.

Koolen-de Vries syndrome (KdVS) is a rare genetic disorder caused by a de novo microdeletion in chromosomal region 17q21.31 encompassing KANSL1 or by a de novo intragenic pathogenic variant of KANSL1. KdVS is typically characterized by intellectual disability (ID), variable from mild to severe, developmental psychomotor delay, especially of expressive language development, friendly disposition, and multiple systemic abnormalities. So far, most of the individuals affected by KdVS are diagnosed in infancy or in adolescence; to the best of our knowledge, only 34 (including ours) adults have been reported in literature. Here we present the adult phenotype of a 63-year-old Italian woman affected by KdVS, caused by a 17q21.31 microdeletion. She is, to our knowledge, the oldest affected individual reported so far. We collected her clinical history and photographs, as well as those of other 26 adult patients described so far and compared her to them. We propose that the cardinal features of KdVS in adulthood are ID (ranging from mild to severe, usually moderate), friendly behavior, musculoskeletal abnormalities (especially scoliosis), and facial dysmorphism (a long face and a pronounced pear-shape nose with bulbous overhanging nasal tip). Therefore, we suggest considering KdVS in differential diagnosis in adult patients characterized by these features.

Identifying phenotypic expansions for congenital diaphragmatic hernia plus (CDH+) using DECIPHER data.

Congenital diaphragmatic hernia (CDH) can occur in isolation or in conjunction with other birth defects (CDH+). A molecular etiology can only be identified in a subset of CDH cases. This is due, in part, to an incomplete understanding of the genes that contribute to diaphragm development. Here, we used clinical and molecular data from 36 individuals with CDH+ who are cataloged in the DECIPHER database to identify genes that may play a role in diaphragm development and to discover new phenotypic expansions. Among this group, we identified individuals who carried putatively deleterious sequence or copy number variants affecting CREBBP, SMARCA4, UBA2, and USP9X. The role of these genes in diaphragm development was supported by their expression in the developing mouse diaphragm, their similarity to known CDH genes using data from a previously published and validated machine learning algorithm, and/or the presence of CDH in other individuals with their associated genetic disorders. Our results demonstrate how data from DECIPHER, and other public databases, can be used to identify new phenotypic expansions and suggest that CREBBP, SMARCA4, UBA2, and USP9X play a role in diaphragm development.

Exome sequencing efficacy and phenotypic expansions involving esophageal atresia/tracheoesophageal fistula plus.

Esophageal atresia/tracheoesophageal fistula (EA/TEF) is a life-threatening birth defect that often occurs with other major birth defects (EA/TEF+). Despite advances in genetic testing, a molecular diagnosis can only be made in a minority of EA/TEF+ cases. Here, we analyzed clinical exome sequencing data and data from the DECIPHER database to determine the efficacy of exome sequencing in cases of EA/TEF+ and to identify phenotypic expansions involving EA/TEF. Among 67 individuals with EA/TEF+ referred for clinical exome sequencing, a definitive or probable diagnosis was made in 11 cases for an efficacy rate of 16% (11/67). This efficacy rate is significantly lower than that reported for other major birth defects, suggesting that polygenic, multifactorial, epigenetic, and/or environmental factors may play a particularly important role in EA/TEF pathogenesis. Our cohort included individuals with pathogenic or likely pathogenic variants that affect TCF4 and its downstream target NRXN1, and FANCA, FANCB, and FANCC, which are associated with Fanconi anemia. These cases, previously published case reports, and comparisons to other EA/TEF genes made using a machine learning algorithm, provide evidence in support of a potential pathogenic role for these genes in the development of EA/TEF.

Positive predictive values and outcomes for uninformative cell-free DNA tests: An Italian multicentric Cytogenetic and cytogenomic Audit of diagnOstic testing (ICARO study).

OBJECTIVES: To establish the positive predictive values (PPV) of cfDNA testing based on data from a nationwide survey of independent clinical cytogenetics laboratories. METHODS: Prenatal diagnostic test results obtained by Italian laboratories between 2013 and March 2020 were compiled for women with positive non-invasive prenatal tests (NIPT), without an NIPT result, and cases where there was sex discordancy between the NIPT and ultrasound. PPV and other summary data were reviewed. RESULTS: Diagnostic test results were collected for 1327 women with a positive NIPT. The highest PPVs were for Trisomy (T) 21 (624/671, 93%) and XYY (26/27, 96.3%), while rare autosomal trisomies (9/47, 19.1%) and recurrent microdeletions (8/55, 14.5%) had the lowest PPVs. PPVs for T21, T18, and T13 were significantly higher when diagnostic confirmation was carried out on chorionic villi (97.5%) compared to amniotic fluid (89.5%) (p < 0.001). In 19/139 (13.9%), of no result cases, a cytogenetic abnormality was detected. Follow-up genetic testing provided explanations for 3/6 cases with a fetal sex discordancy between NIPT and ultrasound. CONCLUSIONS: NIPT PPVs differ across the conditions screened and the tissues studied in diagnostic testing. This variability, issues associated with fetal sex discordancy, and no results, illustrate the importance of pre- and post-test counselling.

3-Methylglutaconic Aciduria Type I Due to AUH Defect: The Case Report of a Diagnostic Odyssey and a Review of the Literature.

3-Methylglutaconic aciduria type I (MGCA1) is an inborn error of the leucine degradation pathway caused by pathogenic variants in the AUH gene, which encodes 3-methylglutaconyl-coenzyme A hydratase (MGH). To date, MGCA1 has been diagnosed in 19 subjects and has been associated with a variable clinical picture, ranging from no symptoms to severe encephalopathy with basal ganglia involvement. We report the case of a 31-month-old female child referred to our center after the detection of increased 3-hydroxyisovalerylcarnitine levels at newborn screening, which were associated with increased urinary excretion of 3-methylglutaconic acid, 3-hydroxyisovaleric acid, and 3-methylglutaric acid. A next-generation sequencing (NGS) panel for 3-methylglutaconic aciduria failed to establish a definitive diagnosis. To further investigate the strong biochemical indication, we measured MGH activity, which was markedly decreased. Finally, single nucleotide polymorphism array analysis disclosed the presence of two microdeletions in compound heterozygosity encompassing the AUH gene, which confirmed the diagnosis. The patient was then supplemented with levocarnitine and protein intake was slowly decreased. At the last examination, the patient showed mild clumsiness and an expressive language disorder. This case exemplifies the importance of the biochemical phenotype in the differential diagnosis of metabolic diseases and the importance of collaboration between clinicians, biochemists, and geneticists for an accurate diagnosis.

Histone Lysine Methylases and Demethylases in the Landscape of Human Developmental Disorders.

Histone lysine methyltransferases (KMTs) and demethylases (KDMs) underpin gene regulation. Here we demonstrate that variants causing haploinsufficiency of KMTs and KDMs are frequently encountered in individuals with developmental disorders. Using a combination of human variation databases and existing animal models, we determine 22 KMTs and KDMs as additional candidates for dominantly inherited developmental disorders. We show that KMTs and KDMs that are associated with, or are candidates for, dominant developmental disorders tend to have a higher level of transcription, longer canonical transcripts, more interactors, and a higher number and more types of post-translational modifications than other KMT and KDMs. We provide evidence to firmly associate KMT2C, ASH1L, and KMT5B haploinsufficiency with dominant developmental disorders. Whereas KMT2C or ASH1L haploinsufficiency results in a predominantly neurodevelopmental phenotype with occasional physical anomalies, KMT5B mutations cause an overgrowth syndrome with intellectual disability. We further expand the phenotypic spectrum of KMT2B-related disorders and show that some individuals can have severe developmental delay without dystonia at least until mid-childhood. Additionally, we describe a recessive histone lysine-methylation defect caused by homozygous or compound heterozygous KDM5B variants and resulting in a recognizable syndrome with developmental delay, facial dysmorphism, and camptodactyly. Collectively, these results emphasize the significance of histone lysine methylation in normal human development and the importance of this process in human developmental disorders. Our results demonstrate that systematic clinically oriented pathway-based analysis of genomic data can accelerate the discovery of rare genetic disorders.

Copy number variation analysis implicates novel pathways in patients with oculo-auriculo-vertebral-spectrum and congenital heart defects.

Oculo-auriculo-vertebral spectrum (OAVS) is a developmental disorder of craniofacial morphogenesis. Its etiology is unclear, but assumed to be complex and heterogeneous, with contribution of both genetic and environmental factors. We assessed the occurrence of copy number variants (CNVs) in a cohort of 19 unrelated OAVS individuals with congenital heart defect. Chromosomal microarray analysis identified pathogenic CNVs in 2/19 (10.5%) individuals, and CNVs classified as variants of uncertain significance in 7/19 (36.9%) individuals. Remarkably, two subjects had small intragenic CNVs involving DACH1 and DACH2, two paralogs coding for key components of the PAX-SIX-EYA-DACH network, a transcriptional regulatory pathway controlling developmental processes relevant to OAVS and causally associated with syndromes characterized by craniofacial involvement. Moreover, a third patient showed a large duplication encompassing DMBX1/OTX3, encoding a transcriptional repressor of OTX2, another transcription factor functionally connected to the DACH-EYA-PAX network. Among the other relevant CNVs, a deletion encompassing HSD17B6, a gene connected with the retinoic acid signaling pathway, whose dysregulation has been implicated in craniofacial malformations, was also identified. Our findings suggest that CNVs affecting gene dosage likely contribute to the genetic heterogeneity of OAVS, and implicate the PAX-SIX-EYA-DACH network as novel pathway involved in the etiology of this developmental trait.

Effects of Metformin and Vitamin D on Clinical Outcome in Cholangiocarcinoma Patients.

BACKGROUND AND AIMS: In the last few years, there has been increasing interest in non-cancer medications and their potential anti-cancer activity. Data are not available in cholangiocarcinoma (CCA) patients. The aim of this study is to fill this gap by investigating the potential impact in terms of clinical outcome of the common non-cancer medications. METHODS: All consecutive patients with CCAs were retrospectively identified from 7 Italian medical institutions. We investigated the role of intake of vitamin D, aspirin, metformin, statins, and diuretics. RESULTS: A total of 537 patients with CCAs were identified; 197 patients undergoing surgery were evaluated for disease-free survival (DFS), and 509 patients with an advanced stage were evaluated for overall survival (OS). A longer DFS was found in patients with intake of vitamin D versus never users (HR 0.55, 95% CI 0.32-0.92, p = 0.02). In an advanced stage an association with OS was found in patients with intake of metformin versus never users (HR 0.70, 95% CI 0.52-0.93, p = 0.0162), and in patients who have started taking metformin after chemotherapy versus before chemotherapy and never users (HR 0.44, 95% CI 0.26-0.73, p = 0.0016). CONCLUSIONS: Our results highlighted that vitamin D intake improves DFS in patients undergoing surgery. Metformin intake after starting chemotherapy can improve the clinical outcome in advanced disease. These results could open up new therapeutic strategies in cholangiocarcinoma patients. We are planning to undertake a prospective study to validate these data.

Genome-Wide DNA Methylation Analysis of a Cohort of 41 Patients Affected by Oculo-Auriculo-Vertebral Spectrum (OAVS).

Oculo-auriculo-vertebral-spectrum (OAVS; OMIM 164210) is a rare disorder originating from abnormal development of the first and second branchial arch. The clinical phenotype is extremely heterogeneous with ear anomalies, hemifacial microsomia, ocular defects, and vertebral malformations being the main features. MYT1, AMIGO2, and ZYG11B gene variants were reported in a few OAVS patients, but the etiology remains largely unknown. A multifactorial origin has been proposed, including the involvement of environmental and epigenetic mechanisms. To identify the epigenetic mechanisms contributing to OAVS, we evaluated the DNA-methylation profiles of 41 OAVS unrelated affected individuals by using a genome-wide microarray-based methylation approach. The analysis was first carried out comparing OAVS patients with controls at the group level. It revealed a moderate epigenetic variation in a large number of genes implicated in basic chromatin dynamics such as DNA packaging and protein-DNA organization. The alternative analysis in individual profiles based on the searching for Stochastic Epigenetic Variants (SEV) identified an increased number of SEVs in OAVS patients compared to controls. Although no recurrent deregulated enriched regions were found, isolated patients harboring suggestive epigenetic deregulations were identified. The recognition of a different DNA methylation pattern in the OAVS cohort and the identification of isolated patients with suggestive epigenetic variations provide consistent evidence for the contribution of epigenetic mechanisms to the etiology of this complex and heterogeneous disorder.

Impact of Aspirin on clinical outcome in advanced HCC patients receiving sorafenib and regorafenib.

BACKGROUND AND AIM: The aim of our retrospective study is to evaluate the prognostic significance of aspirin in patients with advanced HCC treated with sorafenib. METHODS: 304 patients with HCC,consecutively treated with sorafenib from May 2007 to September 2018, were included in the clinical study. Of Them 93 patients token aspirin. Progression-free survival (PFS)and overall survival (OS)were estimated with the Kaplan-Meier method and compared with the log-rank test. RESULTS: The concomitant use of sorafenib and aspirin was associated with a median OS of 18.3 months compared to 8.8 months of patients who did not receive aspirin (HR 0.57; P < 0.0001). The concomitant use of sorafenib and aspirin was associated with a median PFS of 7.3 months compared to 3.0 months of patients who did not receive aspirin (HR 0.61; P = 0.0003). In the multivariate analysis, the use of aspirin maintained an independent prognostic value for OS(HR 0.61; P = 0.0013). In second line the concomitant use of regorafenib and aspirin was associated with a median OS of 16.9 months compared to 8.0 months of patients who did not receive aspirin (HR 0.30; P = 0.02). CONCLUSION: Globally, our data seem to suggest that aspirin use may improve the clinical outcome of patients with advanced hepatocellular carcinoma receiving sorafenib and regorafenib.

Xq22 deletions and correlation with distinct neurological disease traits in females: Further evidence for a contiguous gene syndrome.

Xq22 deletions that encompass PLP1 (Xq22-PLP1-DEL) are notable for variable expressivity of neurological disease traits in females ranging from a mild late-onset form of spastic paraplegia type 2 (MIM# 312920), sometimes associated with skewed X-inactivation, to an early-onset neurological disease trait (EONDT) of severe developmental delay, intellectual disability, and behavioral abnormalities. Size and gene content of Xq22-PLP1-DEL vary and were proposed as potential molecular etiologies underlying variable expressivity in carrier females where two smallest regions of overlap (SROs) were suggested to influence disease. We ascertained a cohort of eight unrelated patients harboring Xq22-PLP1-DEL and performed high-density array comparative genomic hybridization and breakpoint-junction sequencing. Molecular characterization of Xq22-PLP1-DEL from 17 cases (eight herein and nine published) revealed an overrepresentation of breakpoints that reside within repeats (11/17, ~65%) and the clustering of ~47% of proximal breakpoints in a genomic instability hotspot with characteristic non-B DNA density. These findings implicate a potential role for genomic architecture in stimulating the formation of Xq22-PLP1-DEL. The correlation of Xq22-PLP1-DEL gene content with neurological disease trait in female cases enabled refinement of the associated SROs to a single genomic interval containing six genes. Our data support the hypothesis that genes contiguous to PLP1 contribute to EONDT.

ACTB Loss-of-Function Mutations Result in a Pleiotropic Developmental Disorder.

ACTB encodes ß-actin, an abundant cytoskeletal housekeeping protein. In humans, postulated gain-of-function missense mutations cause Baraitser-Winter syndrome (BRWS), characterized by intellectual disability, cortical malformations, coloboma, sensorineural deafness, and typical facial features. To date, the consequences of loss-of-function ACTB mutations have not been proven conclusively. We describe heterozygous ACTB deletions and nonsense and frameshift mutations in 33 individuals with developmental delay, apparent intellectual disability, increased frequency of internal organ malformations (including those of the heart and the renal tract), growth retardation, and a recognizable facial gestalt (interrupted wavy eyebrows, dense eyelashes, wide nose, wide mouth, and a prominent chin) that is distinct from characteristics of individuals with BRWS. Strikingly, this spectrum overlaps with that of several chromatin-remodeling developmental disorders. In wild-type mouse embryos, ß-actin expression was prominent in the kidney, heart, and brain. ACTB mRNA expression levels in lymphoblastic lines and fibroblasts derived from affected individuals were decreased in comparison to those in control cells. Fibroblasts derived from an affected individual and ACTB siRNA knockdown in wild-type fibroblasts showed altered cell shape and migration, consistent with known roles of cytoplasmic ß-actin. We also demonstrate that ACTB haploinsufficiency leads to reduced cell proliferation, altered expression of cell-cycle genes, and decreased amounts of nuclear, but not cytoplasmic, ß-actin. In conclusion, we show that heterozygous loss-of-function ACTB mutations cause a distinct pleiotropic malformation syndrome with intellectual disability. Our biological studies suggest that a critically reduced amount of this protein alters cell shape, migration, proliferation, and gene expression to the detriment of brain, heart, and kidney development.

A new case of SMABF2 diagnosed in stillbirth expands the prenatal presentation and mutational spectrum of ASCC1.

Spinal muscular atrophy with congenital bone fractures 2 (SMABF2) is a rare autosomal recessive neuromuscular disorder characterized by arthrogryposis multiplex congenita and prenatal fractures of the long bones, with poor prognosis. The most affected patients present with biallelic loss-of-function nucleotide variants in ASCC1 gene, coding a subunit of the transcriptional coactivator ASC-1 complex, although the exact pathogenesis is yet unknown. This work describes the first case of SMABF2 in a stillbirth with documented evolution of the disease in the prenatal period. A microdeletion copy number variant (CNV) of about 64 Kb, involving four exons of ASCC1, was firstly detected by microarray analysis, requested for arthrogryposis and hydrops. Subsequent exome analysis disclosed a nucleotide variant of the same gene [c.1027C>T; (p. Arg343*)], resulting in the introduction of a premature termination codon. This stillbirth represents the first case of ASCC1 compound heterozygosity, due to an exonic microdeletion and a nucleotide variant, expanding the mutational spectrum of this gene. It also provides further evidence that exonic CNVs are an underestimated cause of disease-alleles and that the integrated use of the last generation genetic analysis tools, together with careful clinical evaluations, are fundamental for the characterization of rare diseases even in the prenatal setting.

12q21 deletion syndrome: Narrowing the critical region down to 1.6 Mb including SYT1 and PPP1R12A.

Deletions in the 12q21 region are rare and non-recurrent CNVs. To date, only 11 patients with deletions in this region have been reported in the literature. These patients most often presented with syndromic intellectual deficiency, ventriculomegaly or hydrocephalus, ectodermal abnormalities, growth retardation and renal and cardiac malformations, suggesting a recognizable microdeletion syndrome. We report three new patients with overlapping deletions of the 12q21 region, including the smallest deletion reported to date and the first case characterized by array CGH during pregnancy. We describe specific clinical findings and shared facial features as developmental delay, ectodermal abnormalities, ventriculomegaly or hydrocephalus, axial hypotonia or spastic diplegia, growth retardation, heart defect, hydronephrosis, ureteral reflux or horseshoe kidney, large thorax or pectus excavatum, syndactyly of 2-3 toes, pterygium coli or excess nuchal skin, large anterior fontanel, low set ears, prominent forehead, short-upturned nose with nostril hypoplasia, microretrognathia and hypertelorism. These new patients and a comprehensive review of the literature allow us to define a minimum critical region spanning 1.6 Mb in 12q21. By screening the critical region using prediction tools, we identified two candidate genes: SYT1and PPP1R12A.

Delineation of MidXq28-duplication syndrome distal to MECP2 and proximal to RAB39B genes.

Two distinct genomic disorders have been linked to Xq28-gains, namely Xq28-duplications including MECP2 and Int22h1/Int22h2-mediated duplications involving RAB39B. Here, we describe six unrelated patients, five males and one female, with Xq28-gains distal to MECP2 and proximal to the Int22h1/Int22h2 low copy repeats. Comparison with patients carrying overlapping duplications in the literature defined the MidXq28-duplication syndrome featuring intellectual disability, language impairment, structural brain malformations, microcephaly, seizures and minor craniofacial features. The duplications overlapped for 108 kb including FLNA, RPL10 and GDI1 genes, highly expressed in brain and candidates for the neurologic phenotype.