Cri-du-chat syndrome mimics Silver-Russell syndrome depending on the size of the deletion: a case report

BackgroundSilver-Russell Syndrome (SRS) is a rare growth-related genetic disorder mainly characterized by prenatal and postnatal growth failure. Although molecular causes are not clear in all cases, the most common mechanisms involved in SRS are loss of methylation on chromosome 11p15 (approximate to 50%) and maternal uniparental disomy for chromosome 7 (upd(7)mat) (approximate to 10%).Case presentationWe present a girl with clinical suspicion of SRS (intrauterine and postnatal growth retardation, prominent forehead, triangular face, mild psychomotor delay, transient neonatal hypoglycemia, mild hypotonia and single umbilical artery). Methylation and copy number variations at chromosomes 11 and 7 were studied by methylation-specific multiplex ligation-dependent probe amplification and as no alterations were found, molecular karyotyping was performed. A deletion at 5p15.33p15.2 was identified (arr[GRCh37] 5p15.33p15.2(25942-11644643)x1), similar to those found in patients with Cri-du-chat Syndrome (CdCS). CdCS is a genetic disease resulting from a deletion of variable size occurring on the short arm of chromosome 5 (5p-), whose main feature is a high-pitched mewing cry in infancy, accompanied by multiple congenital anomalies, intellectual disability, microcephaly and facial dysmorphism.ConclusionsThe absence of some CdCS features in the current patient could be due to the fact that in her case the critical regions responsible do not lie within the identified deletion. In fact, a literature review revealed a high degree of concordance between the clinical manifestations of the two syndromes.The costs of the publication and molecular analyses of this research were funded by grants from Instituto de Salud Carlos III (Institute of Health Carlos III) of the Spanish Ministry of Economy and Competitiveness, co-financed by the European Regional Development Fund (PI16/00073), the Department of Health of the Basque Government (GV2016111105; GV2017111040), and the University of the Basque Country UPV/EHU (PIF17/29)

Signalling and Bioactive Metabolites from Streptomyces sp. RK44

Q.F. is grateful to the University of Aberdeen Elphinstone Scholarship and Scottish Funding Council/ScotCHEM for financial support through the PEER/PERCE Funding. FM thanks the University of the Philippines for the Faculty, Reps and Staff Development Program (FRAS DP) for the PhD grant fellowship. HD and KK thank the financial supports of Leverhulme Trust-Royal Society Africa award (AA090088) and the jointly funded UK Medical Research Council-UK Department for International Development (MRC/DFID) Concordat agreement African Research Leaders Award (MR/S00520X/1).Peer reviewedPublisher PD

Nutrition recommendations for patients with pseudohypoparathyroidism

Seudohipoparatiroidismo; Hipocalcemia; Balance energéticoPseudohypoparathyroidism; Hypocalcaemia; Energy balanceSeudohipoparatiroïdisme; Hipocalcèmia; Balanç energèticEl seudohipoparatiroidismo (PHP) incluye entidades caracterizadas por la ausencia de respuesta tisular a la acción de la hormona paratiroidea y, en consecuencia, la presencia de hiperfosfatemia e hipocalcemia en grado variable. La obesidad de inicio temprano es una característica de los pacientes con PHP1A. Este artículo plantea la necesidad de establecer unos criterios comunes que orienten el manejo nutricional de estos pacientes. La disminución de su gasto energético implica adaptar el contenido calórico de su alimentación. Reducir el consumo de alimentos ricos en fósforo inorgánico ayuda a manejar la hiperfosfatemia. El consejo nutricional dirigido debe formar parte de la estrategia terapéutica de los niños y adolescentes con PHP, ya que contribuye a modular los desequilibrios en el metabolismo fosfocálcico característicos de estos pacientes.Pseudohypoparathyroidism (PHP) is a spectrum of diseases characterized by insensitivity of target tissues to the action of parathyroid hormone and, consequently, by the presence of hyperphosphatemia and hypocalcaemia of varying severity. Early-onset obesity is a feature of PHP type 1A. This article discusses the need to establish uniform criteria to guide the nutritional management of patients with PHP. A decrease in energy expenditure calls for an adjustment of the energy content of the diet. Reducing the intake of foods rich in inorganic phosphorus helps manage hyperphosphataemia. Targeted nutrition should be part of the treatment plan of children and adolescents with PHP, since it contributes to modulating the calcium and phosphorus metabolism imbalances characteristic of these patients

New pathogenic variant in DLX5: New clues for a clinical spectrum from split-hand-foot malformation to fibular aplasia, tibial campomelia and oligosyndactyly

Introduction: FATCO (Fibular Aplasia, Tibial Campomelia and Oligosyndactyly) is a very infrequent skeletal dysplasia classified within the limb hypoplasia-reduction defects group whose genetic cause has not yet been identified. The advent of next-generation sequencing is enabling the diagnosis of diseases with no previously known genetic cause.Methods: We performed a thorough autopsy on a fetus whose pregnancy was legally terminated due to severe malformations detected by ultrasound. A trio exome was run to identify the genetic cause and risk of recurrence. Previous literature of similar cases was systematically searched.Results: Anatomopathological analyses revealed complete fibular aplasia, shortened and campomelic tibia, absent ankle joint, club right foot and a split foot malformation, leading to the diagnosis of FATCO. Exome sequencing showed that the female fetus carried a de novo nonsense variant in DLX5. The literature search permitted the collection of information on 43 patients with FATCO, the majority of whom were males diagnosed postnatally. In most cases, lower limbs were affected exclusively, but in 39.5% of cases the upper limbs were also affected.Conclusion: The pathologies associated with DLX5 variants encompass a wide spectrum of manifestations ranging from abnormalities exclusively in the hands and feet to long bones such as the tibia and fibula

Imprinting disorders: a group of congenital disorders with overlapping patterns of molecular changes affecting imprinted loci

Congenital imprinting disorders (IDs) are characterised by molecular changes affecting imprinted chromosomal regions and genes, i.e. genes that are expressed in a parent-of-origin specific manner. Recent years have seen a great expansion in the range of alterations in regulation, dosage or DNA sequence shown to disturb imprinted gene expression, and the correspondingly broad range of resultant clinical syndromes. At the same time, however, it has become clear that this diversity of IDs has common underlying principles, not only in shared molecular mechanisms, but also in interrelated clinical impacts upon growth, development and metabolism. Thus, detailed and systematic analysis of IDs can not only identify unifying principles of molecular epigenetics in health and disease, but also support personalisation of diagnosis and management for individual patients and families

Genome-wide DNA methylation analysis of pseudohypoparathyroidism patients with GNAS imprinting defects

Background: Pseudohypoparathyroidism (PHP) is caused by (epi) genetic defects in the imprinted GNAS cluster. Current classification of PHP patients is hampered by clinical and molecular diagnostic overlaps. The European Consortium for the study of PHP designed a genome-wide methylation study to improve molecular diagnosis. Methods: The Human Methylation 450K BeadChip was used to analyze genome-wide methylation in 24 PHP patients with parathyroid hormone resistance and 20 age- and gender-matched controls. Patients were previously diagnosed with GNAS-specific differentially methylated regions (DMRs) and include 6 patients with known STX16 deletion (PHP Delta stx16) and 18 without deletion (PHPneg). Results: The array demonstrated that PHP patients do not show DNA methylation differences at the whole-genome level. Unsupervised clustering of GNAS-specific DMRs divides PHP Delta stx16 versus PHPneg patients. Interestingly, in contrast to the notion that all PHP patients share methylation defects in the A/B DMR while only PHP Delta stx16 patients have normal NESP, GNAS-AS1 and XL methylation, we found a novel DMR (named GNAS-AS2) in the GNAS-AS1 region that is significantly different in both PHP Delta stx16 and PHPneg, as validated by Sequenom EpiTYPER in a larger PHP cohort. The analysis of 58 DMRs revealed that 8/18 PHPneg and 1/6 PHP Delta stx16 patients have multi-locus methylation defects. Validation was performed for FANCC and SVOPL DMRs. Conclusions: This is the first genome-wide methylation study for PHP patients that confirmed that GNAS is the most significant DMR, and the presence of STX16 deletion divides PHP patients in two groups. Moreover, a novel GNAS-AS2 DMR affects all PHP patients, and PHP patients seem sensitive to multi-locus methylation defects

Differences in expression rather than methylation at placenta-specific imprinted loci is associated with intrauterine growth restriction

Background: genome-wide studies have begun to link subtle variations in both allelic DNA methylation and parent-of-origin genetic effects with early development. Numerous reports have highlighted that the placenta plays a critical role in coordinating fetal growth, with many key functions regulated by genomic imprinting. With the recent description of wide-spread polymorphic placenta-specific imprinting, the molecular mechanisms leading to this curious polymorphic epigenetic phenomenon is unknown, as is their involvement in pregnancies complications. Results: profiling of 35 ubiquitous and 112 placenta-specific imprinted differentially methylated regions (DMRs) using high-density methylation arrays and pyrosequencing revealed isolated aberrant methylation at ubiquitous DMRs as well as abundant hypomethylation at placenta-specific DMRs. Analysis of the underlying chromatin state revealed that the polymorphic nature is not only evident at the level of allelic methylation, but DMRs can also adopt an unusual epigenetic signature where the underlying histones are biallelically enrichment of H3K4 methylation, a modification normally mutually exclusive with DNA methylation. Quantitative expression analysis in placenta identified two genes, GPR1-AS1 and ZDBF2, that were differentially expressed between IUGRs and control samples after adjusting for clinical factors, revealing coordinated deregulation at the chromosome 2q33 imprinted locus. Conclusions: DNA methylation is less stable at placenta-specific imprinted DMRs compared to ubiquitous DMRs and contributes to privileged state of the placenta epigenome. IUGR-associated expression differences were identified for several imprinted transcripts independent of allelic methylation. Further work is required to determine if these differences are the cause IUGR or reflect unique adaption by the placenta to developmental stresses

Preimplantation genetic testing for a chr14q32 microdeletion in a family with Kagami-Ogata syndrome and Temple syndrome.

INTRODUCTION: Kagami-Ogata syndrome (KOS14) and Temple syndrome (TS14) are two disorders associated with reciprocal alterations within the chr14q32 imprinted domain. Here, we present a work-up strategy for preimplantation genetic testing (PGT) to avoid the transmission of a causative micro-deletion. METHODS: We analysed DNA from the KOS14 index case and parents using methylation-sensitive ligation-mediated probe amplification and methylation pyrosequencing. The extent of the deletion was mapped using SNP arrays. PGT was performed in trophectoderm samples in order to identify unaffected embryos. Samples were amplified using multiple displacement amplification, followed by genome-wide SNP genotyping to determine the at-risk haplotype and next-generation sequencing to determine aneuploidies. RESULTS: A fully methylated pattern at the normally paternally methylated IG-DMR and MEG3 DMR in the KOS14 proband, accompanied by an unmethylated profile in the TS14 mother was consistent with maternal and paternal transmission of a deletion, respectively. Further analysis revealed a 108 kb deletion in both cases. The inheritance of the deletion on different parental alleles was consistent with the opposing phenotypes. In vitro fertilisation with intracytoplasmatic sperm injection and PGT were used to screen for deletion status and to transfer an unaffected embryo in this couple. A single euploid-unaffected embryo was identified resulting in a healthy baby born. DISCUSSION: We identify a microdeletion responsible for multigeneration KOS14 and TS14 within a single family where carriers have a 50% risk of transmitting the deletion to their offspring. We show that PGT can successfully be offered to couples with IDs caused by genetic anomalies