What Is 22Q11.2 Deletion Syndrome? by Becky L
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Klinefelter, Turner & Down Syndrome
Klinefelter, Turner & Down Syndrome A brief discussion of gamete forma2on, Mitosis and Meiosis: h7ps://www.youtube.com/watch?v=zGVBAHAsjJM Non-disjunction in Meiosis: • Nondisjunction "not coming apart" is the failure of a chromosome pair to separate properly during meiosis 1, or of two chromatids of a chromosome to separate properly during meiosis 2 or mitosis. • Can effect each pair. • Not a rare event. • As a result, one daughter cell has two chromosomes or two chromatids and the other has none • The result of this error is ANEUPLOIDY. 4 haploid gametes 2 gametes with diploid 2 gametes with haploid number of x and 2 lacking number of X chromosome, 1 x chromosome gamete with diploid number of X chromosome, and 1 gamete lacking X chromosome MEIOSIS MITOSIS Nondisjunc2on at meiosis 1 = All gametes will be abnormal Nondisjunc2on at meiosis 2 = Half of the gametes are normal (%50 normal and %50 abnormal) Down’s Syndrome • Karyotype: 47, XY, +21 Three copies of chromosome 21 (21 trisomy) • The incidence of trisomy 21 rises sharply with increasing maternal age (above 37), but Down syndrome can also be the result of nondisjunction of the father's chromosome 21 (%15 of cases) • A small proportion of cases is mosaic* and probably arise from a non-disjunction event in early zygotic division. *“Mosaicism, used to describe the presence of more than one type of cells in a person. For example, when a baby is born with Down syndrome, the doctor will take a blood sample to perform a chromosome study. Typically, 20 different cells are analyzed. -
(Lcrs) in 22Q11 Mediate Deletions, Duplications, Translocations, and Genomic Instability: an Update and Literature Review Tamim H
review January/February 2001 ⅐ Vol. 3 ⅐ No. 1 Evolutionarily conserved low copy repeats (LCRs) in 22q11 mediate deletions, duplications, translocations, and genomic instability: An update and literature review Tamim H. Shaikh, PhD1, Hiroki Kurahashi, MD, PhD1, and Beverly S. Emanuel, PhD1,2 Several constitutional rearrangements, including deletions, duplications, and translocations, are associated with 22q11.2. These rearrangements give rise to a variety of genomic disorders, including DiGeorge, velocardiofacial, and conotruncal anomaly face syndromes (DGS/VCFS/CAFS), cat eye syndrome (CES), and the supernumerary der(22)t(11;22) syndrome associated with the recurrent t(11;22). Chromosome 22-specific duplications or low copy repeats (LCRs) have been directly implicated in the chromosomal rearrangements associated with 22q11.2. Extensive sequence analysis of the different copies of 22q11 LCRs suggests a complex organization. Examination of their evolutionary origin suggests that the duplications in 22q11.2 may predate the divergence of New World monkeys 40 million years ago. Based on the current data, a number of models are proposed to explain the LCR-mediated constitutional rearrangements of 22q11.2. Genetics in Medicine, 2001:3(1):6–13. Key Words: duplication, evolution, 22q11, deletion and translocation Although chromosome 22 represents only 2% of the haploid The 22q11.2 deletion syndrome, which includes DGS/ human genome,1 recurrent, clinically significant, acquired, VCFS/CAFS, is the most common microdeletion syndrome. and somatic -
Dr. Fern Tsien, Dept. of Genetics, LSUHSC, NO, LA Down Syndrome
COMMON TYPES OF CHROMOSOME ABNORMALITIES Dr. Fern Tsien, Dept. of Genetics, LSUHSC, NO, LA A. Trisomy: instead of having the normal two copies of each chromosome, an individual has three of a particular chromosome. Which chromosome is trisomic determines the type and severity of the disorder. Down syndrome or Trisomy 21, is the most common trisomy, occurring in 1 per 800 births (about 3,400) a year in the United States. It is one of the most common genetic birth defects. According to the National Down Syndrome Society, there are more than 400,000 individuals with Down syndrome in the United States. Patients with Down syndrome have three copies of their 21 chromosomes instead of the normal two. The major clinical features of Down syndrome patients include low muscle tone, small stature, an upward slant to the eyes, a single deep crease across the center of the palm, mental retardation, and physical abnormalities, including heart and intestinal defects, and increased risk of leukemia. Every person with Down syndrome is a unique individual and may possess these characteristics to different degrees. Down syndrome patients Karyotype of a male patient with trisomy 21 What are the causes of Down syndrome? • 95% of all Down syndrome patients have a trisomy due to nondisjunction before fertilization • 1-2% have a mosaic karyotype due to nondisjunction after fertilization • 3-4% are due to a translocation 1. Nondisjunction refers to the failure of chromosomes to separate during cell division in the formation of the egg, sperm, or the fetus, causing an abnormal number of chromosomes. As a result, the baby may have an extra chromosome (trisomy). -
Rare Double Aneuploidy in Down Syndrome (Down- Klinefelter Syndrome)
Research Article Journal of Molecular and Genetic Volume 14:2, 2020 DOI: 10.37421/jmgm.2020.14.444 Medicine ISSN: 1747-0862 Open Access Rare Double Aneuploidy in Down Syndrome (Down- Klinefelter Syndrome) Al-Buali Majed J1*, Al-Nahwi Fawatim A2, Al-Nowaiser Naziha A2, Al-Ali Rhaya A2, Al-Khamis Abdullah H2 and Al-Bahrani Hassan M2 1Deputy Chairman of Medical Genetic Unite, Pediatrics Department, Maternity Children Hospital Al-hassa, Hofuf, Saudi Arabia 2Pediatrics Resident, Pediatrics Department, Maternity Children Hospital Alhassa, Hofuf, Saudi Arabia Abstract Background: The chromosomal aneuploidy described as Cytogenetic condition characterized by abnormality in numbers of the chromosome. Aneuploid patient either trisomy or monosomy, can occur in both sex chromosomes as well as autosome chromosomes. However, double aneuploidies involving both sex and autosome chromosomes relatively a rare phenomenon. In present study, we reported a double aneuploidy (Down-Klinefelter syndrome) in infant from Saudi Arabia. Materials and Methods: In the present investigation, chromosomal analysis (standard chromosomal karyotyping) and fluorescence in situ hybridization (FISH) were performed according to the standard protocols. Results: Here, we report a single affected individual (boy) having Saudi origin, suffering from double chromosomal aneuploidy. The main presenting complaint is the obvious dysmorphic features suggesting Down syndrome. Chromosomal analysis and FISH revealed 48,XXY,+21, show the presence of three copies of chromosome 21, two copies of X chromosome and one copy of Y chromosome chromosomes. Conclusion: Patients with Down syndrome must be tested for other associated sex chromosome aneuploidies. Hence, proper diagnosis is needed for proper management and the cytogenetic tests should be performed as the first diagnostic approach. -
Down-Syndrome.Pdf
Down syndrome Description Down syndrome is a chromosomal condition that is associated with intellectual disability, a characteristic facial appearance, and weak muscle tone (hypotonia) in infancy. All affected individuals experience cognitive delays, but the intellectual disability is usually mild to moderate. People with Down syndrome often have a characteristic facial appearance that includes a flattened appearance to the face, outside corners of the eyes that point upward ( upslanting palpebral fissures), small ears, a short neck, and a tongue that tends to stick out of the mouth. Affected individuals may have a variety of birth defects. Many people with Down syndrome have small hands and feet and a single crease across the palms of the hands. About half of all affected children are born with a heart defect. Digestive abnormalities, such as a blockage of the intestine, are less common. Individuals with Down syndrome have an increased risk of developing several medical conditions. These include gastroesophageal reflux, which is a backflow of acidic stomach contents into the esophagus, and celiac disease, which is an intolerance of a wheat protein called gluten. About 15 percent of people with Down syndrome have an underactive thyroid gland (hypothyroidism). The thyroid gland is a butterfly-shaped organ in the lower neck that produces hormones. Individuals with Down syndrome also have an increased risk of hearing and vision problems. Additionally, a small percentage of children with Down syndrome develop cancer of blood-forming cells (leukemia). Delayed development and behavioral problems are often reported in children with Down syndrome. Affected individuals can have growth problems and their speech and language develop later and more slowly than in children without Down syndrome. -
Double Aneuploidy in Down Syndrome
Chapter 6 Double Aneuploidy in Down Syndrome Fatma Soylemez Additional information is available at the end of the chapter http://dx.doi.org/10.5772/60438 Abstract Aneuploidy is the second most important category of chromosome mutations relat‐ ing to abnormal chromosome number. It generally arises by nondisjunction at ei‐ ther the first or second meiotic division. However, the existence of two chromosomal abnormalities involving both autosomal and sex chromosomes in the same individual is relatively a rare phenomenon. The underlying mechanism in‐ volved in the formation of double aneuploidy is not well understood. Parental ori‐ gin is studied only in a small number of cases and both nondisjunctions occurring in a single parent is an extremely rare event. This chapter reviews the characteristics of double aneuploidies in Down syndrome have been discussed in the light of the published reports. Keywords: Double aneuploidy, Down Syndrome, Klinefelter Syndrome, Chromo‐ some abnormalities 1. Introduction With the discovery in 1956 that the correct chromosome number in humans is 46, the new area of clinical cytogenetic began its rapid growth. Several major chromosomal syndromes with altered numbers of chromosomes were reported, such as Down syndrome (trisomy 21), Turner syndrome (45,X) and Klinefelter syndrome (47,XXY). Since then it has been well established that chromosome abnormalities contribute significantly to genetic disease resulting in reproductive loss, infertility, stillbirths, congenital anomalies, abnormal sexual development, mental retardation and pathogenesis of malignancy [1]. Clinical features of patients with common autosomal or sex chromosome aneuploidy is shown in Table 1. © 2015 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. -
Your Baby and Down Syndrome
• • I thought my pregnancy was What will the future hold for my normal. What happened? baby with Down syndrome? About 80% of children with Down People with Down syndrome have some level of Welcoming syndrome are born to mothers under intellectual disability, which can be anywhere your son or age 35. Mothers over 35 have a from mild to severe. Most are somewhere in daughter into higher chance of having a between. No one can look at any infant and the world will baby with Down syndrome. know how intelligent, successful or independent bring joy to you It’s not certain how or why he or she will be in the future. and your family. this happens. Without Your baby will be just specific medical tests, it like other babies in most is impossible to tell if an Today, people with Down unborn child might have ways. He or she will play, enjoy life and like syndrome are achieving more Down syndrome. to learn new things. Like any parent, you with advances in health care and may have some questions about your baby. increased opportunities in education. With support, many can: This brochure is a starting point for learning • move out of the family home about Down syndrome, resources and • take care of themselves support groups. • hold regular jobs • participate in leisure activities congratulations • live rich and full lives answers How might Down syndrome to questions you might have affect my baby’s health? Babies with Down syndrome might be affected What is Down syndrome? What if I want to have another baby? by any of the following health conditions: There are about 350,000 people in the United If you are planning to have more children, ask your • difficulty breastfeeding States with Down syndrome, the most common doctor about your chances for having another child • low muscle tone genetic disorder. -
The Symptom Profile and Experience of Children with Rare Life-Limiting Conditions
The symptom profile and experience of children with rare life-limiting conditions: Perspectives of their families and key health professionals Document Title The symptom profile and experience of children with rare life-limiting conditions: Perspectives of their families and key health professionals Authors Cari Malcolm, Sally Adams, Gillian Anderson, Faith Gibson, Richard Hain, Anthea Morley, Liz Forbat. Publisher Cancer Care Research Centre, University of Stirling Publication Date 2011 Target Audience Paediatric palliative care staff, paediatric clinicians, policy-makers, service developers, families supporting children with life-limiting conditions. Funded By Children’s Hospice Association Scotland Key Words Advance care planning, Batten disease, expertise, extended family, family, Morquio disease, progressive life-limiting, relationships, Sanfilippo disease, siblings, symptoms. Contact Details www.cancercare.stir.ac.uk Tel: 01786 849260 Email: [email protected] Copyright This publication is copyright CCRC and may be reproduced free of charge in any format or medium. Any material used must be fully acknowledged, and the title of the publication, authors and date of publication specified. The symptom profile and experience of children with rare life- limiting conditions: Perspectives of their families and key health professionals Executive Summary Background Many non-malignant life-limiting conditions are individually extremely rare and little is known, even by professionals in the field, about the actual day-to-day symptomatology or the impact of these symptoms on the child and family. With little recorded in the literature regarding the symptoms that children with rare life-limiting conditions experience, and the associated impact of managing these symptoms on the wider family, an opportunity exists to widen the knowledge base in this area. -
Aggression, Rage and Dyscontrol in Neurological Diseases of Children
Journal of Pediatric Neurology 2003; 1(1): 9-14 www.jpneurology.org REVIEW ARTICLE Aggression, rage and dyscontrol in neurological diseases of children Jayaprakash A. Gosalakkal University Hospitals of Leicester, Leicestershire and Warwick Medical School, Leicester, U.K. Abstract that aggression has a neuroanatomic and chemical basis, that developmental and acquired brain Behavioral neurology has been bridging disorders contribute to recurrent interpersonal the gap between neurology and psychiatry in violence, that both biologic and sociologic factors children. There are several neuropsychiatric are involved, and that to ignore either is to invite disorders of children in which aggression is a error (2). dominant symptom. Both global disorders like There are several neuropsychiatric disorders attention deficit hyperactivity disorder as well of children in which aggression is a dominant as localized dysfunction of the brain may lead symptom e.g. Lesch-Nyhan syndrome, Prader-Willi to aggression. A number of neurometabolic syndrome etc (Tables 1 and 2). Self-mutilation has disorders as well as post-epileptic and post- been seen in 15% of institutionalized mentally surgical states may present with aggression retarded patients (3). Physical and verbal aggression in children. Drugs are sometimes effective may also be a symptom of frontal lobe epilepsy in especially in combination with a multimode children in association with other psychological approach. In this review some of the more deficits (4). Rage outbursts and increased aggression common causes for aggression in neurologically have been noted to occur in higher rates in children impaired children, the associated co-morbidities with temporal lobe epilepsy (5). and treatment are discussed. (J Pediatr Neurol Aggression can be seen both in previously 2003; 1(1): 9-14). -
Chromosome 22Q11.2 Deletion Syndrome (Digeorge and Velocardiofacial Syndromes) Elena Perez, MD, Phd, and Kathleen E
Chromosome 22q11.2 deletion syndrome (DiGeorge and velocardiofacial syndromes) Elena Perez, MD, PhD, and Kathleen E. Sullivan, MD, PhD Chromosome 22q11.2 deletion syndrome occurs in Overview approximately 1 of 3000 children. Clinicians have defined the Chromosome 22q11.2 deletion syndrome is the name phenotypic features associated with the syndrome and the given to a heterogeneous group of disorders that share a past 5 years have seen significant progress in determining the common genetic basis. Most patients with DiGeorge frequency of the deletion in specific populations. As a result, syndrome and velocardiofacial syndrome have monoso- caregivers now have a better appreciation of which patients mic deletions of chromosome 22q11.2 [1,2]. Other syn- are at risk for having the deletion. Once identified, patients dromes in which a substantial fraction of patients have with the deletion can receive appropriate multidisciplinary care. been determined to have the deletion are conotruncal We describe recent advances in understanding the genetic anomaly face syndrome,Caylor cardiofacial syndrome, basis for the syndrome, the clinical manifestations of the and autosomal dominant Opitz-G/BBB syndrome. Com- syndrome, and new information on autoimmune diseases in plicating the situation further is the fact that not all pa- this syndrome. Curr Opin Pediatr 2002, 14:678–683 © 2002 Lippincott tients with hemizygous deletions of chromosome Williams & Wilkins, Inc. 22q11.2 have identical deletions. Despite the heteroge- neity of both the clinical manifestations and the chromo- somal deletions,much progress has been made in the last year in understanding the genetic basis of the chromo- some 22q11.2 deletion syndromes. -
Digeorge Syndrome in a Newborn - a Diagnostic Challenge
Carvalho V, et al., J Neonatol Clin Pediatr 2020, 7: 061 DOI: 10.24966/NCP-878X/100061 HSOA Journal of Neonatology and Clinical Pediatrics Case Report manifestations in order to allow anearly multidisciplinary orientation, DiGeorge Syndrome in a as well as to provide genetic counseling to the patient’s relatives. Keywords: 22q11 Deletion syndrome; Combined syndromic immu- Newborn - A Diagnostic no deficiencies; DiGeorge syndrome Challenge Introduction Vasco Carvalho1, Raquel Oliveira1, Joana Vilaça1, Miguel Gonçalves Rocha2, Almerinda Pereira1 and Nicole Silva1 DiGeorge Syndrome (DGS) is mainly caused by the microdeletion of chromosome 22 (22q11.2), being characterized by a broad pheno- 1 Neonatal Intensive Care Unit, Department of Pediatrics, Hospital of Braga, typic spectrum [1-10]. Braga, Portugal 2Genetics Service, Hospital of Braga, Braga, Portugal The microdeletion of chromosome 22q11.2 results in maldevel- opment of both the third and fourth pharyngeal pouches and it is the most common interstitial deletion syndrome, affecting approximate- Abstract ly 1 in every 2.000-6.000 live births, with males and females being Introduction: DiGeorge syndrome is mainly caused by microdele- equally affected [3-5,8-13]. tion of chromosome 22 (22q11.2) and is characterized by a broad phenotypic spectrum. Approximately 90 percent of the patients with DGS have hetero- zygous deletions in chromosome 22q11.2 and typically result from de Description of case: A 35-year-old healthy primigravida was novo microdeletions, therefore supporting a high rate of spontaneous hospitalized due to preterm labor at 29 weeks and four days. deletion. It is important to add that about 10% of the cases are famil- Parents were non-consanguineous with unremarkable family history. -
Cryptic Subtelomeric Translocations in the 22Q13 Deletion Syndrome J Med Genet: First Published As 10.1136/Jmg.37.1.58 on 1 January 2000
58 J Med Genet 2000;37:58–61 Cryptic subtelomeric translocations in the 22q13 deletion syndrome J Med Genet: first published as 10.1136/jmg.37.1.58 on 1 January 2000. Downloaded from Verayuth Praphanphoj, Barbara K Goodman, George H Thomas, Gerald V Raymond Abstract lieved to result from de novo, simple, subtelom- Cryptic subtelomeric rearrangements eric deletions,1–9 two cases were derived from are suspected to underlie a substantial balanced translocations,49 one case was the portion of terminal chromosomal dele- result of a familial chromosome 22 inversion,10 tions. We have previously described two and in one case the mechanism was not children, one with an unbalanced subtelo- determined.11 (It is possible that one of these meric rearrangement resulting in dele- cases may have been reported twice,17in which tion of 22q13→qter and duplication of case the total number would be 21 cases and the 1qter, and a second with an apparently simple deletions would be 17 cases.) This report simple 22q13→qter deletion. We have describes the clinical findings in a new case of examined two additional patients with 22q13→qter deletion and the identification of deletions of 22q13→qter. In one of the new translocated material on the deleted chromo- patients presented here, clinical findings some using multi-telomere fluorescence in situ were suggestive of the 22q13 deletion syn- hybridisation (FISH). drome and FISH for 22qter was re- Recent data indicate that some apparently quested. Chromosome studies suggested terminal chromosome deletions are, in fact, an abnormality involving the telomere of derivative chromosomes involving cryptic termi- one 22q (46,XX,?add(22)(q13.3)).