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1.
Am J Hum Genet ; 108(3): 502-516, 2021 03 04.
Article in English | MEDLINE | ID: mdl-33596411

ABSTRACT

Deletion 1p36 (del1p36) syndrome is the most common human disorder resulting from a terminal autosomal deletion. This condition is molecularly and clinically heterogeneous. Deletions involving two non-overlapping regions, known as the distal (telomeric) and proximal (centromeric) critical regions, are sufficient to cause the majority of the recurrent clinical features, although with different facial features and dysmorphisms. SPEN encodes a transcriptional repressor commonly deleted in proximal del1p36 syndrome and is located centromeric to the proximal 1p36 critical region. Here, we used clinical data from 34 individuals with truncating variants in SPEN to define a neurodevelopmental disorder presenting with features that overlap considerably with those of proximal del1p36 syndrome. The clinical profile of this disease includes developmental delay/intellectual disability, autism spectrum disorder, anxiety, aggressive behavior, attention deficit disorder, hypotonia, brain and spine anomalies, congenital heart defects, high/narrow palate, facial dysmorphisms, and obesity/increased BMI, especially in females. SPEN also emerges as a relevant gene for del1p36 syndrome by co-expression analyses. Finally, we show that haploinsufficiency of SPEN is associated with a distinctive DNA methylation episignature of the X chromosome in affected females, providing further evidence of a specific contribution of the protein to the epigenetic control of this chromosome, and a paradigm of an X chromosome-specific episignature that classifies syndromic traits. We conclude that SPEN is required for multiple developmental processes and SPEN haploinsufficiency is a major contributor to a disorder associated with deletions centromeric to the previously established 1p36 critical regions.


Subject(s)
Chromosome Disorders/genetics , Chromosomes, Human, Pair 1/genetics , Chromosomes, Human, X/genetics , DNA-Binding Proteins/genetics , RNA-Binding Proteins/genetics , Adolescent , Autism Spectrum Disorder/genetics , Autism Spectrum Disorder/pathology , Child , Child, Preschool , Chromosome Deletion , Chromosome Disorders/physiopathology , DNA Methylation/genetics , Epigenesis, Genetic/genetics , Female , Haploinsufficiency/genetics , Humans , Intellectual Disability/genetics , Intellectual Disability/physiopathology , Male , Neurodevelopmental Disorders/genetics , Neurodevelopmental Disorders/physiopathology , Phenotype , Young Adult
2.
Am J Med Genet A ; 194(3): e63459, 2024 Mar.
Article in English | MEDLINE | ID: mdl-37927205

ABSTRACT

Neurodevelopmental disorders exhibit recurrent facial features that can suggest the genetic diagnosis at a glance, but recognizing subtle dysmorphisms is a specialized skill that requires very long training. Face2Gene (FDNA Inc) is an innovative computer-aided phenotyping tool that analyses patient's portraits and suggests 30 candidate syndromes with similar morphology in a prioritized list. We hypothesized that the software could support even expert physicians in the diagnostic workup of genetic conditions. In this study, we assessed the performance of Face2Gene in an Italian dysmorphological pediatrics clinic. We uploaded two-dimensional face pictures of 145 children affected by genetic conditions with typical phenotypic traits. All diagnoses were previously confirmed by cytogenetic or molecular tests. Overall, the software's differential included the correct syndrome in most cases (98%). We evaluated the efficiency of the algorithm even considering the rareness of the genetic conditions. All "common" diagnoses were correctly identified, most of them with high diagnostic accuracy (93% in top-3 matches). Finally, the performance for the most common pediatric syndromes was calculated. Face2Gene performed well even for ultra-rare genetic conditions (75% within top-3 matches and 83% within top-10 matches). Expert geneticists maybe do not need computer support to recognize common syndromes, but our results prove that the tool can be useful not only for general pediatricians but also in dysmorphological clinics for ultra-rare genetic conditions.


Subject(s)
Algorithms , Image Processing, Computer-Assisted , Child , Humans , Retrospective Studies , Image Processing, Computer-Assisted/methods , Syndrome , Italy
3.
Am J Med Genet A ; 194(5): e63512, 2024 May.
Article in English | MEDLINE | ID: mdl-38135466

ABSTRACT

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.


Subject(s)
De Lange Syndrome , Humans , De Lange Syndrome/diagnosis , De Lange Syndrome/genetics , Cell Cycle Proteins/genetics , Mosaicism , Phenotype
4.
Am J Med Genet A ; 194(7): e63577, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38421079

ABSTRACT

SMC1A epilepsy syndrome or developmental and epileptic encephalopathy-85 with or without midline brain defects (DEE85, OMIM #301044) is an X-linked neurologic disorder associated with mutations of the SMC1A gene, which is also responsible for about 5% of patients affected by Cornelia de Lange syndrome spectrum (CdLS). Only described in female patients, SMC1A epilepsy syndrome is characterized by the onset of severe refractory epileptic seizures in the first year of life, global developmental delay, a variable degree of intellectual disability, and dysmorphic facial features not typical of CdLS. This was a descriptive observational study for the largest international cohort with this specific disorder. The main goal of this study was to improve the knowledge of the natural history of this phenotype with particular attention to the psychomotor development and the epilepsy data. The analyzed cohort shows normal prenatal growth with the subsequent development of postnatal microcephaly. The incidence of neonatal problems (seizures and respiratory compromise) is considerable (51.4%). There is a significant prevalence of central nervous system (20%) and cardiovascular malformations (20%). Motor skills are generally delayed. The presence of drug-resistant epilepsy is confirmed; the therapeutic role of a ketogenic diet is still uncertain. The significant regression of previously acquired skills following the onset of seizures has been observed. Facial dysmorphisms are variable and no patient shows a classic CdLS phenotype. To sum up, SMC1A variants caused drug-resistant epilepsy in these patients, more than two-thirds of whom were shown to progress to developmental and epileptic encephalopathy. The SMC1A gene variants are all different from each other (apart from a couple of monozygotic twins), demonstrating the absence of a mutational hotspot in the SMC1A gene. Owing to the absence of phenotypic specificity, whole-exome sequencing is currently the diagnostic gold standard.


Subject(s)
Cell Cycle Proteins , Chromosomal Proteins, Non-Histone , Mutation , Humans , Female , Male , Cell Cycle Proteins/genetics , Chromosomal Proteins, Non-Histone/genetics , Child, Preschool , Infant , Mutation/genetics , Child , Epilepsy/genetics , Epilepsy/epidemiology , Epilepsy/pathology , Epilepsy/diagnosis , Phenotype , Cohort Studies , Adolescent , Infant, Newborn , Epileptic Syndromes/genetics , Epileptic Syndromes/epidemiology , De Lange Syndrome/genetics , De Lange Syndrome/epidemiology , De Lange Syndrome/pathology
5.
Nat Rev Genet ; 19(10): 649-666, 2018 10.
Article in English | MEDLINE | ID: mdl-29995837

ABSTRACT

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.


Subject(s)
De Lange Syndrome , High-Throughput Nucleotide Sequencing , Mutation , Consensus , De Lange Syndrome/diagnosis , De Lange Syndrome/genetics , De Lange Syndrome/physiopathology , De Lange Syndrome/therapy , Genetic Association Studies , Humans
6.
J Med Genet ; 60(2): 163-173, 2023 02.
Article in English | MEDLINE | ID: mdl-35256403

ABSTRACT

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.


Subject(s)
Vascular Malformations , Humans , Mutation/genetics , Phenotype , Genotype , Class I Phosphatidylinositol 3-Kinases/genetics , Vascular Malformations/diagnosis , Vascular Malformations/genetics , p120 GTPase Activating Protein/genetics
7.
Acta Paediatr ; 2024 May 27.
Article in English | MEDLINE | ID: mdl-38801140

ABSTRACT

AIM: We aimed to evaluate the impact of Coronavirus Disease-19 (COVID-19) pandemic on the incidence and clinical presentation of celiac disease (CD) in children. METHODS: The diagnoses of CD were compared between the COVID-19 pandemic (from April 2020 to March 2022) and the pre-pandemic period (from April 2018 to March 2020) in three Italian Paediatric Gastroenterology centres (Varese, Como, Catanzaro). Electronic patient records were reviewed and additional information were collected through parental interview. The diagnosis of CD was made according to ESPGHAN criteria. SARS-CoV-2 infection was diagnosed based on pre-vaccination positive serum antibodies or nasopharyngeal swabs. Z test and chi-square were used for statistical analysis. RESULTS: The overall number of paediatric diagnosis of CD did not differ between the two years pre-pandemic and pandemic periods (177 and 172 cases) in the three Italian participating centres. Clinical presentation of CD was also similar throughout the study periods. SARS-CoV-2 infection has been documented in 10.6% of children but only in 5.8% of these occurred before CD diagnosis. CONCLUSION: Different to what reported for other autoimmune diseases, the incidence and presenting symptoms of CD in our paediatric population did not change during the COVID-19 pandemic compared to the previous 2 years.

8.
Hum Genet ; 142(6): 785-808, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37079061

ABSTRACT

Deleterious variants in collagen genes are the most common cause of hereditary connective tissue disorders (HCTD). Adaptations of the American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) criteria are still lacking. A multidisciplinary team was set up for developing specifications of the ACMG/AMP criteria for COL1A1, COL1A2, COL2A1, COL3A1, COL5A1, COL5A2, COL11A1, COL11A2 and COL12A1, associated with various forms of HCTD featuring joint hypermobility, which is becoming one of the most common reasons of referral for molecular testing in this field. Such specifications were validated against 209 variants, and resulted effective for classifying as pathogenic and likely pathogenic null alleles without downgrading of the PVS1 level of strength and recurrent Glycine substitutions. Adaptations of selected criteria reduced uncertainties on private Glycine substitutions, intronic variants predicted to affect the splicing, and null alleles with a downgraded PVS1 level of strength. Segregation and multigene panel sequencing data mitigated uncertainties on non-Glycine substitutions by the attribution of one or more benignity criteria. These specifications may improve the clinical utility of molecular testing in HCTD by reducing the number of variants with neutral/conflicting interpretations. Close interactions between laboratory and clinicians are crucial to estimate the a priori utility of molecular test and to improve medical reports.


Subject(s)
Genetic Variation , Joint Instability , Humans , United States , Genetic Testing/methods , Joint Instability/diagnosis , Joint Instability/genetics , Sequence Analysis, DNA/methods
9.
Am J Hum Genet ; 107(4): 753-762, 2020 10 01.
Article in English | MEDLINE | ID: mdl-32910914

ABSTRACT

Lamin B1 plays an important role in the nuclear envelope stability, the regulation of gene expression, and neural development. Duplication of LMNB1, or missense mutations increasing LMNB1 expression, are associated with autosomal-dominant leukodystrophy. On the basis of its role in neurogenesis, it has been postulated that LMNB1 variants could cause microcephaly. Here, we confirm this hypothesis with the identification of de novo mutations in LMNB1 in seven individuals with pronounced primary microcephaly (ranging from -3.6 to -12 SD) associated with relative short stature and variable degree of intellectual disability and neurological features as the core symptoms. Simplified gyral pattern of the cortex and abnormal corpus callosum were noted on MRI of three individuals, and these individuals also presented with a more severe phenotype. Functional analysis of the three missense mutations showed impaired formation of the LMNB1 nuclear lamina. The two variants located within the head group of LMNB1 result in a decrease in the nuclear localization of the protein and an increase in misshapen nuclei. We further demonstrate that another mutation, located in the coil region, leads to increased frequency of condensed nuclei and lower steady-state levels of lamin B1 in proband lymphoblasts. Our findings collectively indicate that de novo mutations in LMNB1 result in a dominant and damaging effect on nuclear envelope formation that correlates with microcephaly in humans. This adds LMNB1 to the growing list of genes implicated in severe autosomal-dominant microcephaly and broadens the phenotypic spectrum of the laminopathies.


Subject(s)
Dwarfism/genetics , Intellectual Disability/genetics , Lamin Type B/genetics , Microcephaly/genetics , Mutation , Nuclear Lamina/genetics , Amino Acid Sequence , Base Sequence , Cerebral Cortex/diagnostic imaging , Cerebral Cortex/metabolism , Cerebral Cortex/pathology , Child, Preschool , Corpus Callosum/diagnostic imaging , Corpus Callosum/metabolism , Corpus Callosum/pathology , Dwarfism/diagnostic imaging , Dwarfism/metabolism , Dwarfism/pathology , Female , Gene Expression , Humans , Infant , Intellectual Disability/diagnostic imaging , Intellectual Disability/metabolism , Intellectual Disability/pathology , Lamin Type B/metabolism , Lymphocytes/metabolism , Lymphocytes/pathology , Magnetic Resonance Imaging , Male , Microcephaly/diagnostic imaging , Microcephaly/metabolism , Microcephaly/pathology , Nuclear Lamina/metabolism , Nuclear Lamina/pathology
10.
Am J Med Genet A ; 191(3): 823-830, 2023 03.
Article in English | MEDLINE | ID: mdl-36420948

ABSTRACT

Here we describe three patients with neurodevelopmental disorders characterized by mild-to-moderate intellectual disability, mildly dysmorphic features, and hirsutism, all of which carry de novo sequence variants in the WW domain-containing adaptor of the coiled-coil (WAC) gene; two of these-c.167delA, p.(Asn56I1efs*136) and c.1746G>C, p.(Gln582His)-are novel pathogenic variants, and the third-c.1837C>T, p(Arg613*)-has been previously described. Diseases associated with WAC include DeSanto-Shinawi syndrome; to date, de novo heterozygous constitutional pathogenic WAC variants have caused a syndromic form of intellectual disability and mild dysmorphic features in 33 patients, yet potential associations with other clinical manifestations, such as oligomenorrhea and hyperandrogenism, remain unknown, because the phenotypic spectrum of the condition has not yet been delineated. The patient bearing the novel c.167delA WAC gene variant presented a normal psychomotor development, oligomenorrhea, hyperandrogenism, and hirsutism, and hirsutism was also observed in the patient with the c.1746G>C WAC gene variant. Hypertrichosis and hirsutism have been described in nine DeSanto-Shinawi patients, only in 17 of the 33 aforementioned patients thus far reported this aspect, and no hormonal-pattern data are available. In conclusion, we note that the pathogenic c.167delA WAC variant may be associated with a mild phenotype; and in addition to the neurodevelopmental problems nearly all DeSanto-Shinawi patients experience (i.e., intellectual disability and/or developmental delay), we recommend the addition of mild dysmorphic features, hirsutism, and hypertrichosis to this clinical presentation.


Subject(s)
Hyperandrogenism , Hypertrichosis , Intellectual Disability , Humans , Female , Intellectual Disability/genetics , Hirsutism/genetics , Hypertrichosis/genetics , Oligomenorrhea , Phenotype
11.
Am J Med Genet A ; 191(2): 424-436, 2023 02.
Article in English | MEDLINE | ID: mdl-36373849

ABSTRACT

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.


Subject(s)
De Lange Syndrome , Rubinstein-Taybi Syndrome , Humans , Rubinstein-Taybi Syndrome/genetics , Rubinstein-Taybi Syndrome/psychology , Longitudinal Studies , Cross-Sectional Studies , De Lange Syndrome/diagnosis , De Lange Syndrome/genetics , Phenotype
12.
Am J Med Genet A ; 191(1): 84-89, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36254687

ABSTRACT

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.


Subject(s)
Autoimmune Diseases , Celiac Disease , Williams Syndrome , Humans , Young Adult , Adult , Celiac Disease/complications , Celiac Disease/epidemiology , Celiac Disease/genetics , Williams Syndrome/complications , Williams Syndrome/epidemiology , Williams Syndrome/genetics , Transglutaminases , Haplotypes , Genetic Predisposition to Disease
13.
Genome Res ; 29(7): 1057-1066, 2019 07.
Article in English | MEDLINE | ID: mdl-31160375

ABSTRACT

Germline mutations in fundamental epigenetic regulatory molecules including DNA methyltransferase 3 alpha (DNMT3A) are commonly associated with growth disorders, whereas somatic mutations are often associated with malignancy. We profiled genome-wide DNA methylation patterns in DNMT3A c.2312G > A; p.(Arg771Gln) carriers in a large Amish sibship with Tatton-Brown-Rahman syndrome (TBRS), their mosaic father, and 15 TBRS patients with distinct pathogenic de novo DNMT3A variants. This defined widespread DNA hypomethylation at specific genomic sites enriched at locations annotated as genes involved in morphogenesis, development, differentiation, and malignancy predisposition pathways. TBRS patients also displayed highly accelerated DNA methylation aging. These findings were most marked in a carrier of the AML-associated driver mutation p.Arg882Cys. Our studies additionally defined phenotype-related accelerated and decelerated epigenetic aging in two histone methyltransferase disorders: NSD1 Sotos syndrome overgrowth disorder and KMT2D Kabuki syndrome growth impairment. Together, our findings provide fundamental new insights into aberrant epigenetic mechanisms, the role of epigenetic machinery maintenance, and determinants of biological aging in these growth disorders.


Subject(s)
Aging/genetics , DNA (Cytosine-5-)-Methyltransferases/genetics , Epigenesis, Genetic , Growth Disorders/genetics , Mutation , Abnormalities, Multiple/genetics , Adolescent , Adult , Amish/genetics , Child , DNA Methylation , DNA Methyltransferase 3A , Face/abnormalities , Hematologic Diseases/genetics , Humans , Intellectual Disability/genetics , Leukemia, Myeloid, Acute/genetics , Male , Methyltransferases , Morphogenesis/genetics , Syndrome , Vestibular Diseases/genetics , Young Adult
14.
Genet Med ; 24(1): 51-60, 2022 01.
Article in English | MEDLINE | ID: mdl-34906459

ABSTRACT

PURPOSE: Chromatinopathies include more than 50 disorders caused by disease-causing variants of various components of chromatin structure and function. Many of these disorders exhibit unique genome-wide DNA methylation profiles, known as episignatures. In this study, the methylation profile of a large cohort of individuals with chromatinopathies was analyzed for episignature detection. METHODS: DNA methylation data was generated on extracted blood samples from 129 affected individuals with the Illumina Infinium EPIC arrays and analyzed using an established bioinformatic pipeline. RESULTS: The DNA methylation profiles matched and confirmed the sequence findings in both the discovery and validation cohorts. Twenty-five affected individuals carrying a variant of uncertain significance, did not show a methylation profile matching any of the known episignatures. Three additional variant of uncertain significance cases with an identified KDM6A variant were re-classified as likely pathogenic (n = 2) or re-assigned as Wolf-Hirschhorn syndrome (n = 1). Thirty of the 33 Next Generation Sequencing negative cases did not match a defined episignature while three matched Kabuki syndrome, Rubinstein-Taybi syndrome and BAFopathy respectively. CONCLUSION: With the expanding clinical utility of the EpiSign assay, DNA methylation analysis should be considered part of the testing cascade for individuals presenting with clinical features of Mendelian chromatinopathy disorders.


Subject(s)
Abnormalities, Multiple , Hematologic Diseases , Vestibular Diseases , DNA Methylation/genetics , Genome , Humans
15.
Am J Med Genet A ; 188(8): 2434-2437, 2022 08.
Article in English | MEDLINE | ID: mdl-35670300

ABSTRACT

Spondylo-epi-metaphyseal dysplasia Shohat type (SEMDSH, OMIM # 602557) is a rare skeletal dysplasia. Until recently, only eight patients of five families have been reported. The disorder is characterized by severely disproportionate short stature with a short neck, small trunk with abdominal distension, and short lower limbs. Joint laxity and bowed legs are seen. The same homozygous splicing pathogenic variant in the DDRGK1 gene was found in four Iraqi families. Here we report a homozygous missense pathogenic variant in DDRGK1 in two children from unrelated two Moroccan families. The clinical and radiological phenotypes of the affected children were similar to those previously described.


Subject(s)
Dwarfism , Osteochondrodysplasias , Homozygote , Humans , Mutation , Mutation, Missense/genetics , Osteochondrodysplasias/diagnostic imaging , Osteochondrodysplasias/genetics , Pedigree
16.
Am J Med Genet A ; 188(6): 1661-1666, 2022 06.
Article in English | MEDLINE | ID: mdl-35243770

ABSTRACT

Cantù syndrome (CS) is a rare multisystemic disorder, characterized by congenital hypertrichosis, macrocephaly, facial dysmorphisms, cardiomegaly, vascular, and skeletal anomalies. From the cognitive point of view, most of the patients show a mild speech delay and a few of them present intellectual disability and learning difficulties. To date, most CS-reported cases are caused by heterozygous ABCC9 gene mutations. Only three patients with CS and heterozygous KCNJ8 gene variants have been reported. The authors here present the fourth case of CS with a variant in KCNJ8 in a 6-month-old baby. Diagnosis was reached through Trio-Whole Exome analysis that revealed a de novo missense variant in KCNJ8.


Subject(s)
Hypertrichosis , Osteochondrodysplasias , Cardiomegaly/genetics , Humans , Hypertrichosis/diagnosis , Hypertrichosis/genetics , Infant , Mutation, Missense/genetics , Osteochondrodysplasias/genetics
17.
Int J Mol Sci ; 23(11)2022 May 25.
Article in English | MEDLINE | ID: mdl-35682590

ABSTRACT

KBG syndrome (KBGS) is a neurodevelopmental disorder caused by the Ankyrin Repeat Domain 11 (ANKRD11) haploinsufficiency. Here, we report the molecular investigations performed on a cohort of 33 individuals with KBGS clinical suspicion. By using a multi-testing genomic approach, including gene sequencing, Chromosome Microarray Analysis (CMA), and RT-qPCR gene expression assay, we searched for pathogenic alterations in ANKRD11. A molecular diagnosis was obtained in 22 out of 33 patients (67%). ANKRD11 sequencing disclosed pathogenic or likely pathogenic variants in 18 out of 33 patients. CMA identified one full and one terminal ANKRD11 pathogenic deletions, and one partial duplication and one intronic microdeletion, with both possibly being pathogenic. The pathogenic effect was established by RT-qPCR, which confirmed ANKRD11 haploinsufficiency only for the three deletions. Moreover, RT-qPCR applied to six molecularly unsolved KBGS patients identified gene downregulation in a clinically typical patient with previous negative tests, and further molecular investigations revealed a cryptic deletion involving the gene promoter. In conclusion, ANKRD11 pathogenic variants could also involve the regulatory regions of the gene. Moreover, the application of a multi-test approach along with the innovative use of RT-qPCR improved the diagnostic yield in KBGS suspected patients.


Subject(s)
Abnormalities, Multiple , Bone Diseases, Developmental , Intellectual Disability , Tooth Abnormalities , Abnormalities, Multiple/genetics , Chromosome Deletion , Facies , Humans , Intellectual Disability/genetics , Phenotype , Repressor Proteins/genetics , Tooth Abnormalities/diagnosis , Tooth Abnormalities/genetics , Transcription Factors/genetics
18.
Hum Mol Genet ; 28(1): 64-73, 2019 01 01.
Article in English | MEDLINE | ID: mdl-30239720

ABSTRACT

Cornelia de Lange syndrome (CdLS), which is reported to affect ∼1 in 10 000 to 30 000 newborns, is a multisystem organ developmental disorder with relatively mild to severe effects. Among others, intellectual disability represents an important feature of this condition. CdLS can result from mutations in at least five genes: nipped-B-like protein, structural maintenance of chromosomes 1A, structural maintenance of chromosomes 3, RAD21 cohesin complex component and histone deacetylase 8 (HDAC8). It is believed that mutations in these genes cause CdLS by impairing the function of the cohesin complex (to which all the aforementioned genes contribute to the structure or function), disrupting gene regulation during critical stages of early development. Since intellectual disorder might result from alterations in neural development, in this work, we studied the role of Hdac8 gene in mouse neural stem cells (NSCs) and in vertebrate (Danio rerio) brain development by knockdown and chemical inhibition experiments. Underlying features of Hdac8 deficiency is an increased cell death in the developing neural tissues, either in mouse NSCs or in zebrafish embryos.


Subject(s)
Cell Cycle Proteins/physiology , Chromosomal Proteins, Non-Histone/physiology , De Lange Syndrome/genetics , Histone Deacetylases/genetics , Animals , Cell Cycle Proteins/genetics , Cell Differentiation/genetics , Cell Differentiation/physiology , Chromosomal Proteins, Non-Histone/genetics , De Lange Syndrome/physiopathology , Gene Expression Regulation/genetics , Histone Deacetylases/metabolism , Histone Deacetylases/physiology , Male , Mice , Mice, Inbred C57BL , Mutation/genetics , Neural Stem Cells/physiology , Neurons/physiology , Phenotype , Repressor Proteins/genetics , Zebrafish , Zebrafish Proteins , Cohesins
19.
Clin Genet ; 100(2): 187-200, 2021 08.
Article in English | MEDLINE | ID: mdl-33955014

ABSTRACT

Mutations affecting the transcriptional regulator Ankyrin Repeat Domain 11 (ANKRD11) are mainly associated with the multisystem developmental disorder known as KBG syndrome, but have also been identified in individuals with Cornelia de Lange syndrome (CdLS) and other developmental disorders caused by variants affecting different chromatin regulators. The extensive functional overlap of these proteins results in shared phenotypical features, which complicate the assessment of the clinical diagnosis. Additionally, re-evaluation of individuals at a later age occasionally reveals that the initial phenotype has evolved toward clinical features more reminiscent of a developmental disorder different from the one that was initially diagnosed. For this reason, variants in ANKRD11 can be ascribed to a broader class of disorders that fall within the category of the so-called chromatinopathies. In this work, we report on the clinical characterization of 23 individuals with variants in ANKRD11. The subjects present primarily with developmental delay, intellectual disability and dysmorphic features, and all but two received an initial clinical diagnosis of either KBG syndrome or CdLS. The number and the severity of the clinical signs are overlapping but variable and result in a broad spectrum of phenotypes, which could be partially accounted for by the presence of additional molecular diagnoses and distinct pathogenic mechanisms.


Subject(s)
Abnormalities, Multiple/etiology , Bone Diseases, Developmental/etiology , Intellectual Disability/etiology , Repressor Proteins/genetics , Tooth Abnormalities/etiology , Abnormalities, Multiple/genetics , Adolescent , Bone Diseases, Developmental/genetics , Child , Child, Preschool , Face/abnormalities , Facies , Female , Humans , Intellectual Disability/genetics , Male , Mutation , Pedigree , Tooth Abnormalities/genetics , Young Adult
20.
Am J Med Genet A ; 185(2): 390-396, 2021 02.
Article in English | MEDLINE | ID: mdl-33174385

ABSTRACT

Williams-Beuren syndrome (WBS) is caused by an haploinsufficiency of the 7q11.2 region which involves the elastin gene (ELN). A deficiency of elastin is a known pathophysiological mechanism of emphysema/chronic obstructive pulmonary disease (COPD). A previous study hypothesized a higher risk of COPD in WBS patients. Herein, this phenomenon was further investigated looking for a possible correlation between COPD and WBS. Dynamic lung volumes (forced vital capacity [FVC], FEV1, FEV1/FVC) were measured in 22 patients (age range 18.9 ± 7.4 years) affected with WBS, genetically confirmed, correlating these parameters to respiratory risk factors. Dyspnea, cough and wheezing were detected in 6/22 (27%) patients. Obstructive and restrictive patterns were identified in 6/22 (27%) and 2/22 (9%) cases, respectively with no evidence of irreversible obstruction. CVF, FEV1 and FEV1/CVF mean values were all normal, with values of 91.3% (n.v. > 80%), 84.2% (n.v. > 80%) and 0.82 (n.v. > 0.7), respectively. The severity of the comorbidities did not show a cause-effect relation with the respiratory patterns, nevertheless patients treated with anti-hypertensive drugs had poorer pulmonary function. Our findings are in accordance with previous observations, showing that emphysema/COPD is not a typical finding in young patients with WBS. However, a respiratory function assessment should be included in the follow-up of WBS patients, especially in adolescents/young adults under treatment with anti-hypertensive drugs.


Subject(s)
Lung/physiopathology , Pulmonary Disease, Chronic Obstructive/genetics , Pulmonary Emphysema/genetics , Williams Syndrome/genetics , Adolescent , Adult , Child , Elastin/metabolism , Female , Humans , Italy/epidemiology , Male , Middle Aged , Pulmonary Disease, Chronic Obstructive/diagnosis , Pulmonary Disease, Chronic Obstructive/physiopathology , Pulmonary Emphysema/diagnosis , Pulmonary Emphysema/pathology , Respiratory Function Tests , Risk Factors , Spirometry , Vital Capacity/physiology , Williams Syndrome/diagnosis , Williams Syndrome/physiopathology , Young Adult
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