Characteristic Facial Features Research Articles

How to provide a genetic counseling in a simple case of antenatal diagnosis of achondroplasia

Achondroplasia is the most common form of inherited disproportionate short stature. Affected individuals have short arms and legs, a large head, and characteristic facial features with frontal bossing and midface retrusion, formerly known as midface hypoplasia. Mode of inheritance of achondroplasia is autosomal dominant. Two mutations in FGFR3, G380R and G375C are known to cause achondroplasia. The G380R mutation accounts for 98% of the achondroplasia cases. Here we review the ultrasound, radiographic and clinical features, genetic aspects and molecular pathogenesis of the most common form of dwarfism in humans, providing a model of genetic counseling given to a family with an antenatal diagnosis of a fetal genetic disorder, due to a novel mutation, as a part of the feto-maternal diagnostic strategy.

A twin sibling with Prader-Willi syndrome caused by type 2 microdeletion following assisted reproductive technology: A case report.

Prader-Willi syndrome (PWS) is a neurobehavioral imprinting disorder, which arises due to an absence of paternally expressed genes within the 15q11.2-q13 region. This occurs via one of the three main genetic mechanisms, as follows: Deletion of the paternally inherited 15q11.2-q13 region, maternal uniparental disomy and imprinting defect. Recent studies have reported an association between imprinting disorders and assisted reproductive technologies (ART). The current study presents a 6-year-old female patient who is a dizygotic twin, in which one was born with de novo microdeletion at 15q11.2-q13.1 following in vitro fertilization. The patient had characteristic facial features including narrow bifrontal diameter, strabismus, downturned mouth, feeding problems and generalized hypotonia during infancy, developmental delay, mental retardation and rapid weight gain. Based upon phenotypic resemblance and the medical records, methylation-specific multiplex ligation-dependent probe amplification and array-based comparative genome hybridization analyses demonstrate type 2 microdeletion between breaking point 2 (BP2) and BP3, which occur from MKRN3 through HERC2 at 15q11.2-q13.1. To the best of our knowledge, the present study is the first to report a PWS case born following ART reported in South Korea. In addition to previous studies, the present study contributes to the consensus regarding genotype-phenotype comparisons in this respect.

53. A Neuro-Specific Gene Therapy Approach to Treat Cognitive Impairment in Down Syndrome by RNA Interference

Down syndrome (DS) is a genetic disorder caused by the presence of a third copy of chromosome 21. DS affects multiple organs, resulting in characteristic facial features, muscular hypotonia, heart defects, brain development impairment, and varying degrees of intellectual disability. Trisomic mouse models of DS reproduce the main cognitive disabilities of the human syndrome. In particular, DS mice show structural and functional synaptic impairment as well as learning and memory deficits, largely determined by altered GABAergic transmission through chloride-permeable GABAa receptors (GABAaR). In particular, we have recently found that intracellular chloride accumulation shifts GABAAR-mediated signaling from inhibitory to excitatory in the adult brain of the Ts65Dn mouse model of DS. Accordingly, intracellular chloride accumulation was paralleled by increased expression of the chloride importer NKCC1 (Na-K-Cl cotransporter) in the brains of both trisomic mice and DS patients. Our findings on NKCC1 as a pivotal molecular target for the rescue of cognitive deficits in DS opens the possibility of a gene therapy approach to treat the disease. Here, to normalize NKCC1 expression and rescue synaptic dysfunctions as well as cognitive deficits in Ts65Dn mice we have developed and characterized a knock-down approach to normalize NKCC1 activity. Reducing the expression of the chloride importer NKCC1 by RNA interference restored GABAAR-mediated inhibition and also rescued the structural dendritic deficits found in trisomic neurons in vitro. Most importantly, focal administration of an AAV expressing a silencing RNA under the transcriptional control of a neuron-specific promoter in the hippocampus of Ts65Dn animals mediated NKCC1 knockdown in vivo and rescued behavioral performance on different learning and memory tests at levels undistinguishable from those of WT mice. Our findings demonstrate that NKCC1 overexpression drives excitatory GABAAR signaling in trisomic cells, leading to structural neuronal abnormalities and behavioral impairments in DS mice. Moreover, our study identifies a new gene therapy target for treatments aimed at rescuing cognitive disabilities in individuals with DS.

New developments in Silver-Russell syndrome and implications for clinical practice.

Silver-Russell syndrome is a clinically and genetically heterogeneous disorder, characterized by prenatal and postnatal growth restriction, relative macrocephaly, body asymmetry and characteristic facial features. It is one of the imprinting disorders, which results as a consequence of aberrant imprinted gene expressions. Currently, maternal uniparental disomy of chromosome 7 accounts for approximately 10% of Silver-Russell syndrome cases, while ~50% of patients have hypomethylation at imprinting control region 1 at chromosome 11p15.5 locus, leaving ~40% of cases with unknown etiologies. This review aims to provide a comprehensive list of molecular defects in Silver-Russell syndrome reported to date and to highlight the importance of multiple-loci/tissue testing and trio (both parents and proband) screening. The epigenetic and phenotypic overlaps with other imprinting disorders will also be discussed.

Perioperative Care of an Infant With Wolf-Hirschhorn Syndrome: Is There a Risk of Malignant Hyperthermia

Wolf-Hirschhorn (WH) syndrome is a rare chromosomal abnormality with deletion of the short arm of chromosome 4. Associated clinical signs and symptoms of the condition include intrauterine growth restriction, severe psychomotor retardation, failure to thrive, characteristic facial features, profound developmental delays, seizures, and various congenital midline fusion anomalies. Given the associated congenital anomalies, anesthetic care may be required for various surgical interventions. We report a 3-month-old girl with WH syndrome scheduled for gastrostomy tube placement. Previous reports of anesthetic care for such patients are reviewed and potential perioperative concerns are discussed. J Med Cases. 2016;7(4):126-129 doi: http://dx.doi.org/10.14740/jmc2418w

Maternally inherited autosomal dominant intellectual disability caused by 16p13.3 microduplication

A 16p13.3 duplication syndrome has been recently suggested to be a novel recognizable syndrome as a reciprocal microduplication disease of Rubinstein–Taybi syndrome. The CREBBP gene is believed to be the dosage-sensitive critical gene responsible for the reciprocal duplication and deletion syndrome. Descriptions so far have been de novo. Here, we report a very rare case of a maternally inherited a −1 Mb sized duplication on 16p13.3 identified by SNP array testing. The patient showed moderate intellectual disability, normal growth, and characteristic facial features. The patient's mother also had mild intellectual disability, normal growth, camptodactyly, proximally implanted small thumbs, and distinctive facial features. The study provides additional information that furthers the understanding and delineation of 16p13.3 duplication syndrome.

A series of 38 novel germline and somatic mutations of NIPBL in Cornelia de Lange syndrome.

Cornelia de Lange syndrome is a multisystemic developmental disorder mainly related to de novo heterozygous NIPBL mutation. Recently, NIPBL somatic mosaicism has been highlighted through buccal cell DNA study in some patients with a negative molecular analysis on leukocyte DNA. Here, we present a series of 38 patients with a Cornelia de Lange syndrome related to a heterozygous NIPBL mutation identified by Sanger sequencing. The diagnosis was based on the following criteria: (i) intrauterine growth retardation and postnatal short stature, (ii) feeding difficulties and/or gastro-oesophageal reflux, (iii) microcephaly, (iv) intellectual disability, and (v) characteristic facial features. We identified 37 novel NIPBL mutations including 34 in leukocytes and 3 in buccal cells only. All mutations shown to have arisen de novo when parent blood samples were available. The present series confirms the difficulty in predicting the phenotype according to the NIPBL mutation. Until now, somatic mosaicism has been observed for 20 cases which do not seem to be consistently associated with a milder phenotype. Besides, several reports support a postzygotic event for those cases. Considering these elements, we recommend a first-line buccal cell DNA analysis in order to improve gene testing sensitivity in Cornelia de Lange syndrome and genetic counselling.

Differing Microdeletion Sizes and Breakpoints in Chromosome 7q11.23 in Williams-Beuren Syndrome Detected by Chromosomal Microarray Analysis

Williams-Beuren syndrome (WBS) manifests as supravalvular aortic stenosis, intellectual disability, developmental delay and characteristic facial features. The common WBS deletion region ranges from 1.55 to 1.84 Mb and primarily contains the ELN gene. We analyzed 10 patients diagnosed with 7q11.23 microdeletion syndrome by chromosomal microarray analysis. The clinical features of these patients varied from classic WBS to normal phenotype. All 10 patients exhibited different sizes and breakpoints of chromosome microdeletions ranging from 44 kb to 9.88 Mb. The hemizygosity of the ELN gene was detected in 7 patients, while a normal ELN gene was present in 3 other patients with small deletions. We observed that the phenotypic features of WBS varied in fetuses, children and adults, influenced by the genes, deletion size and breakpoint. Our findings provide more information on the genotype-phenotype correlations of WBS. However, further research is needed to explore the size and breakpoint effect and functions of the genes on chromosome 7q11.23.

Prader-Willi Syndrome: A spectrum of anatomical and clinical features.

Prader-Willi Syndrome (PWS) is estimated to affect 400,000 people worldwide. First described clinically in 1956, PWS is now known to be a result of a genetic mutation, involving Chromosome 15. The phenotypical appearance of individuals with the syndrome follows a similar developmental course. During infancy, universal hypotonia accompanied by feeding problems, hypogonadism, and dolichocephaly are evident. Characteristic facial features such as narrow bifrontal diameter, almond-shaped eyes, and small mouth (with downturned corners and thin upper lip) may also be evident at this stage. In early childhood, the craniofacial features become more obvious and a global developmental delay is observed. Simultaneously, individuals develop hyperphagia that leads to excessive or rapid weight gain, which, if untreated, exists throughout their lifespan and may predispose them to numerous, serious health issues. The standard tool for differential diagnosis of PWS is genetic screening; however, clinicians also need to be aware of the characteristic features of this disorder, including differences between the genetic subtypes. As the clinical manifestations of the syndrome vary between individuals and become evident at different developmental time points, early assessment is hindered. This article focuses on the clinical and anatomical manifestations of the syndrome and highlights the areas of discrepancy and limitations within the existing literature. Clin. Anat. 29:590-605, 2016. © 2016 Wiley Periodicals, Inc.

De Novo Loss-of-Function Mutations in USP9X Cause a Female-Specific Recognizable Syndrome with Developmental Delay and Congenital Malformations

Mutations in more than a hundred genes have been reported to cause X-linked recessive intellectual disability (ID) mainly in males. In contrast, the number of identified X-linked genes in which de novo mutations specifically cause ID in females is limited. Here, we report 17 females with de novo loss-of-function mutations in USP9X, encoding a highly conserved deubiquitinating enzyme. The females in our study have a specific phenotype that includes ID/developmental delay (DD), characteristic facial features, short stature, and distinct congenital malformations comprising choanal atresia, anal abnormalities, post-axial polydactyly, heart defects, hypomastia, cleft palate/bifid uvula, progressive scoliosis, and structural brain abnormalities. Four females from our cohort were identified by targeted genetic testing because their phenotype was suggestive for USP9X mutations. In several females, pigment changes along Blaschko lines and body asymmetry were observed, which is probably related to differential (escape from) X-inactivation between tissues. Expression studies on both mRNA and protein level in affected-female-derived fibroblasts showed significant reduction of USP9X level, confirming the loss-of-function effect of the identified mutations. Given that some features of affected females are also reported in known ciliopathy syndromes, we examined the role of USP9X in the primary cilium and found that endogenous USP9X localizes along the length of the ciliary axoneme, indicating that its loss of function could indeed disrupt cilium-regulated processes. Absence of dysregulated ciliary parameters in affected female-derived fibroblasts, however, points toward spatiotemporal specificity of ciliary USP9X (dys-)function.

Perioperative Care of an Infant With Wolf-Hirschhorn Syndrome: Is There a Risk of Malignant Hyperthermia

Wolf-Hirschhorn (WH) syndrome is a rare chromosomal abnormality with deletion of the short arm of chromosome 4. Associated clinical signs and symptoms of the condition include intrauterine growth restriction, severe psychomotor retardation, failure to thrive, characteristic facial features, profound developmental delays, seizures, and various congenital midline fusion anomalies. Given the associated congenital anomalies, anesthetic care may be required for various surgical interventions. We report a 3-month-old girl with WH syndrome scheduled for gastrostomy tube placement. Previous reports of anesthetic care for such patients are reviewed and potential perioperative concerns are discussed. J Med Cases. 2016;7(4):126-129 doi: http://dx.doi.org/10.14740/jmc2418w

Cytogenetic study of down syndrome in Algeria: Report and review

Background: Down syndrome (DS) is the most common type of chromosomal trisomy found in newborn. It is associated with mental retardation and characteristic facial features. A clinical diagnosis of DS may be unconfirmed in one-third of cases. Objective: This study was conducted to confirm the clinical diagnosis of suspected cases with DS by a cytogenetic analysis and to evaluate several risk factors associated with trisomy 21 in a group of patients from West region of Algeria, Tlemcen. Materials and Methods: Karyotype analysis was carried out for 22 patients with the clinical diagnosis of DS. GTG-band and RTG-band have been made according to the standard protocols. Results: Among the 22 cases with DS, free trisomy 21 was presented in 20 cases (91%). One case (4.5%) had translocation DS. One other case had mosaic DS. There was an excess of male than female; sex ratio was 1.75:1. The mean maternal age at birth of the affected children was 36.27 ± 7.59 years. It was significantly higher than this of mothers of nontrisomic children (27.83 ± 6.34 years; P = 0.0002). Higher parity was an important risk factor associated with trisomy 21, 81% of affected children were of last or second last birth order. Paternal age and consanguinity had no effect. Conclusion: The identification of specific types of chromosomal abnormalities in DS children is very significant. It greatly helped in the management of these children and to make aware the affected families about the recurrence risk and the options available.

Cytogenetic Study of Down Syndrome In Algeria: Report and Review

Background: Down syndrome (DS) is the most common type of chromosomal trisomy found in new-born. It’s associated with mental retardation and characteristic facial features. A clinical diagnosis of Down syndrome may be unconfirmed in one third of cases. Objective: This study was conducted to confirm the clinical diagnosis of suspected cases with Down syndrome by a cytogenetic analysis and to evaluate several risk factors associated with trisomy 21 in a group of patients from West region of Algeria, Tlemcen. Materials and method: Karyotype analysis was carried out for 22 patients with the clinical diagnosis of Down syndrome. GTG- band and RTG-band have been made according to the standard protocols. Results: Among the 22 cases with Down syndrome, Free trisomy 21 was presented in 20 cases (91%). One case (4.5%) had translocation Down syndrome. One other case had mosaic Down syndrome. There was an excess of male than female; sex ratio was 1.75:1. The mean maternal age at birth of the affected children was 36.27 ± 7.59 years. It was significantly higher than this of mothers of non-trisomic children (27.83 ± 6.34 years; p=0.0002). Higher parity was an important risk factor associated with trisomy 21, 81% of affected children were of last or second last birth order. Paternal age and consanguinity had no effect. Conclusion: The identification of specific types of chromosomal abnormalities in Down syndrome children is very significant. It greatly helped in the management of these children and to make aware the affected families about the recurrence risk and the options available.

An Interstitial Deletion at 7q33-36.1 in a Patient with Intellectual Disability, Significant Language Delay, and Severe Microcephaly.

Interstitial deletions of the distal 7q region are considered a rare entity. In this report, we describe a seven-year-old male with a heterozygous interstitial deletion at 7q33-36.1 with characteristic dysmorphic facial features, intellectual disability, severe microcephaly, and significant language delay. The primary focus of our report is to compare our case with the few others in the literature describing interstitial deletions at the long arm of chromosome 7. Based on the various breakpoints in prior studies, a number of phenotypic variations have been identified that are unique to each of the reports. However, there are also a number of similarities among these cases as well. We hope to provide a concise review of the literature and genes involved within our deletion sequence in the hope that it will contribute to creating a phenotypic profile for this patient population.

Gli2 gene-environment interactions contribute to the etiological complexity of holoprosencephaly: evidence from a mouse model.

ABSTRACTHoloprosencephaly (HPE) is a common and severe human developmental abnormality marked by malformations of the forebrain and face. Although several genetic mutations have been linked to HPE, phenotypic outcomes range dramatically, and most cases cannot be attributed to a specific cause. Gene-environment interaction has been invoked as a premise to explain the etiological complexity of HPE, but identification of interacting factors has been extremely limited. Here, we demonstrate that mutations in Gli2, which encodes a Hedgehog pathway transcription factor, can cause or predispose to HPE depending upon gene dosage. On the C57BL/6J background, homozygous GLI2 loss of function results in the characteristic brain and facial features seen in severe human HPE, including midfacial hypoplasia, hypotelorism and medial forebrain deficiency with loss of ventral neurospecification. Although normally indistinguishable from wild-type littermates, we demonstrate that mice with single-allele Gli2 mutations exhibit increased penetrance and severity of HPE in response to low-dose teratogen exposure. This genetic predisposition is associated with a Gli2 dosage-dependent attenuation of Hedgehog ligand responsiveness at the cellular level. In addition to revealing a causative role for GLI2 in HPE genesis, these studies demonstrate a mechanism by which normally silent genetic and environmental factors can interact to produce severe outcomes. Taken together, these findings provide a framework for the understanding of the extreme phenotypic variability observed in humans carrying GLI2 mutations and a paradigm for reducing the incidence of this morbid birth defect.

MG-106 Global developmental delay and characteristic facial features associated with pacs1 gene mutation – report of two cases

Intellectual disability (ID) affects 1%–3% of the population. While it has a strong genetic component, finding a genetic diagnosis remains challenging. Given the high rate of de novo events in ID, family-based sequencing may be an important tool. In 2012 Schuurs-Hoeijmakers et al ., reported two children with ID and characteristic features associated with a heterozygote mutation in PACS1. We report the same mutation elucidated by whole exome sequencing (WES) in two additional children. Patient 1 was born at term to a 30-year-old primigravida from Bangladesh. Her birth weight and length were 3–10th% and head circumference 50–75th%. ID presented in the first year of life. She had sparse hair, a high forehead, frontal bossing, hypertelorism, deep-set eyes, a broad nasal root, full lips and a wide mouth. She had marked hypotonia, decreased muscle bulk and hyperextensible joints. WES revealed a PACS1 mutation. (NM_018026)exon4:c. C607T:p. R203W. Patient 2 was born at term to a 34-year-old primigravida from China. Birth weight and length were 10–25th% and head circumference 25–50th%. At birth, an anoplasty was performed for an ectopic anus. A right duplex kidney and undescended testes were identified. ID presented before age one. He had a short forehead, bushy eyebrows, short nose, large mouth, uplifting earlobes, bilateral single palmar creases, widely spaced nipples and an umbilical hernia. WES revealed the same mutation. Our two cases highlight the clinical utility of WES in helping establish a diagnosis of an unfamiliar clinical syndrome and supports the discovery of a now recognisable syndrome due to mutation in PACS1.

ABORDAREA TERAPEUTICĂ INTERDISCIPLINARĂ A PACIENTULUI CU SINDROM DOWN

Down syndrome is a genetic disorder that occurs at an average frequency of 1 in 800 births. This syndrome, which develops as a result of the triplication of chromosome 21, is associated with characteristic facial features, mild to moderate intellectual disability, physical growth delays, characteristic facial features, low muscle tone. Orthodontic treatment in a patient with Down syndrome represents a real challenge, both in terms of the complex manifestations of this syndrome (whether they are systemic manifestations or strictly oral manifestations) and in terms of collaboration with specialists in other medical fields and more. This case illustrates the effectiveness of cooperation within the multidisciplinary treatment team and also the good collaboration with the pacient and especially with his parents.

Cases of Trichohepatoenteric Syndrome (Syndromic Diarrhea) with Underlying Crohn’s Disease

Tricho-hepato-enteric syndrome (syndromic, phenotypic diarrhea, SD/THES) is a rare inborn disease, which affects bowels. It is caused by the mutation of genes SKIV2L or TTC37. Manifestations include intrauterine hypotrophy, severe chronic diarrhea, which starts in infancy, characteristic facial features and hair growth abnormalities, immune disorders. There are data on two patients dealing with tricho-hepato-enteric syndrome with underlying Crohn’s disease. This is the first description of cases of aggravated tricho-hepatoenteric syndrome ever found in Russian medical literature.

Overexpression of the LSAMP and TUSC7 genes in acute myeloid leukemia following microdeletion/duplication of chromosome 3

The 3q13.31 microdeletion syndrome is characterized by developmental delay, postnatal growth above the mean, characteristic facial features, and abnormal male genitalia. Moreover, a frequent deletion in the 3q13.31 chromosome region has been identified in patients who are affected by osteosarcomas. Among the genes located within the deleted region, the involvement of the limbic system-associated membrane protein gene (LSAMP), together with a non-coding RNA tumor suppressor candidate 7 gene (TUSC7), has been suggested. We describe the case of an adult acute myeloid leukemia (AML) patient with a novel chromosomal rearrangement characterized by a 3q13.31 microdeletion and an extra copy of the 3q13.31-q29 chromosomal region translocated to the long arm of the Y chromosome. This karyotypic aberration seems to cause LSAMP and TUSC7 gene expression dysregulation. In conclusion, we report the first case of LSAMP and TUSC7 gene overexpression, possibly due to a position effect in an AML patient bearing a 3q13.31 cryptic deletion.

Post-childhood Presentation and Diagnosis of DiGeorge Syndrome.

The diversity of clinical presentations makes the diagnosis of DiGeorge syndrome (DGS) a diagnostic challenge. The objective of our study was to report the clinical presentation of DGS in the post-childhood period. A retrospective study, investigating patients diagnosed clinically and genetically with DGS at Sheba Medical Center during the period of 2010-2013. Post-childhood period was defined as age >10 years. During the study period, 29 patients were diagnosed with DGS. Nine (31%) patients with DGS were diagnosed in their post-childhood period. The basis for clinical suspicion was diverse. However, once the suspicion was brought to attention, additional symptoms consistent with DGS were noted at up to 88% of patients who presented characteristic of facial features and developmental delay. Our research shows that diagnosing DGS patients in the post-childhood period is not uncommon. Characteristic facial features and developmental delay, although not leading presenting symptoms, are found very frequently in patients with DGS.