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Chromosome Abnormalities in Children


Chromosomal Abnormalities in Children

Chromosome abnormalities in children are caused by either of thefollowing mitosis, maternal age or meiosis. Meiosis normally occurswhen there is an error in cell division during the development of thesperm and egg cell. Mitosis is also an error in cell division thatoccurs later after the egg and sperm have developed. Maternal agecomes with the age of the mother complication here arises because theeggs of a woman are as old as the mother thus, poses a risk ofchromosomal abnormality to the unborn child. In the United States, itis estimated that out of every 150 children born one of them suffersfrom a chromosomal abnormality. Chromosomal abnormalities cause arange of abnormalities to the unborn child and on some cases causesdeath of the fetus or embryo before the child can be born.

Chromosomal abnormalities are diagnosed using a blood test afterbirth or prenatal test before birth. The cells obtained are thentaken to the lab for test after growth. The assess the arrangement ofthe cell after and makes karyotype pictures which show shape, numberand type of chromosomes thus aiding in the identification of anyabnormalities. The most common type of chromosomal abnormality is theDown syndrome. It is estimated that out of every 800 newborn babiesone of them suffers from this syndrome. Other chromosomal abnormalityinclude trisomy, sex chromosomes abnormalities, turner syndrome, andKlinefelter syndrome. There other less common abnormalities of thechromosomal deletion, duplication, inversion, microdeletion andtranslocation and ring chromosomal. In seeking, treatment parentshould consult doctors help, additionally, even though the chancesare slim it is paramount for parent to seek medical help if a motheris pregnant and has had a baby earlier with a chromosomalabnormality.

Prognostic importance ofstructural chromosomal abnormalities in children with hyperdiploid(greater than 50 chromosomes), hyperdiploid is a widespreadcytogenetic abnormality in childhood B-cell precursor ALL (AcuteLymphoblastic Leukemia).

Highhyperdiploid ALL cytogenetically trait are a nonrandom X chromosomesgain. Many questions remain despite high frequency of karyotypicsubgroup these questions are related to etiology, genetic changes,cell origin, epidemiology, high hyperdiploid pathogeneticconsequences and its formation. Several studies have been carried outin the recent past, these studies focus on some basic importantissues about hyperdiploid chromosomal abnormality1.A good example of this studies is “Prognostic importance ofstructural chromosomal abnormalities in children with hyperdiploid(greater than 50 chromosomes) acute lymphoblastic leukemia,”Conducted by National Center for Biotechnology Information (1989).

According to this study, it is estimated that in every four childrenwho are diagnosed with ALL that is acute Lymphoblastic leukemia, oneof them has high hyperdiploid (greater than 50 chromosomes).Unfortunately, most of these children fail to get therapy. The studyinvestigated 138 children 68 girls and 70 boys who had ALLhyperdiploid (greater than 50 chromosomes) with the aim of assessingthe cytogenetic and initial clinical features, which might foretelltreatment failure. The result of this study was as follows 85children that are 62% of the total had structural chromosomalabnormalities laboratory and clinical features of this group were nodifferent from the 53 case of those with numeric abnormalities only1.There were 28 failures in this study after a follow-up of four years.Male gender and structural chromosomal abnormalities presence wereindependently linked to treatment failure after multivariateanalysis. Thus, structural chromosomal abnormalities in hyperdiploid(greater than 50 chromosomes) ALL gives a different definition ofbiologically different leukemia form which is characterized by drugresistance likelihood.

Chromosome abnormalities found among 34910 newborn children:results from 13-year incidence study in Arhus, Denmark: thisstudy was conducted by Johannes Nielsen and Mogen Wohlert with an aimof finding out how environment factors affect pregnancy, fetus andbirth. The 13 year old incidence research on sex chromosomeabnormality showed that at least 1 out of every 448 newborn had anabnormality in the sex chromosome. Klinefelter syndrome and Turnersyndrome were the most common abnormalities according to the studyfindings. Of the 78 surviving children who had sex chromosomeabnormalities none had a mental retardation. The children who hadreached school age attended the regular schools2.

Those with Klinefelter, XYY or XXX and aged 15-19, approximately 77%of this group had at one time received remedial teaching. Moreover,29 were in the process of receiving the remedial teaching.Furthermore, 32% had at one point received special classes due toproblems in learning, 24% of them were still continuing with theclasses when the follow up was conducted. The sample group showed noincrease in criminal activity frequency or behavior disorder. Inaddition to this, there was no increased physical nor mentaldisorder. The planned distribution in terms of training andoccupation of the 25 youth aged 15-19 with sex chromosomeabnormalities was the same as their sibs2. Klinefelterboys were administered testosterone undecanoate treatment frompuberty while as the Turner girls from the age of 7 were administeredwith growth hormone treatment. Girls with turners’ syndrome at theage of 12 were given estrogen doses.

From this study, we run that reduction and prevention in mentaldevelopment deviation from normality for a child with sex chromosomesabnormalities is possible. This can be achieved if parent iscounseled and informed regularly and if social resources andeducation are availed to those in need.

This study paper addressed all the four sex chromosomes abnormalitiesthat XXX, Klinefelter syndrome, Turner syndrome and XYY. The studyproposes that the support, information, and support groups should befacilitated to parent with children with these challenges. Inaddition to this, parent needs assistance an counseling depending ontheir child condition, the parent resource in term of finance,socially, psychologically and precise sex chromosome abnormality2.

Therapy-related myelodysplastic syndrome and acute myeloidleukemia in children: correlation between chromosomal abnormalitiesand prior therapy. According to scientist this two conditions arethought to be a result mutation events caused by radiation therapy,chemotherapy, immunosuppressive therapy or pre-existing conditions.In a study conducted by Rubin CM and others on this topic, theresults showed that most children with therapy related Acute myeloidLeukemia or myelodysplastic syndrome (MDS) had in one way or theother being exposed to either epipodophyllotoxin and alkylatingagent3.

The study was conducted on a sample of 20 children with AML that isAcute Myeloid Leukemia or Myelodysplastic Syndrome (MDS). The agebracket for primary neoplasm was between six months to sixteen yearsof age while as for secondary neoplasm was 1-24. In this group, 12had chromosomal abnormalities3. Ten of the twelve had beenat one time exposed to therapy related to either MDS or AML. MDS andAML are therapy related clinical syndrome that results as acomplication that comes after cytotoxic therapy3.

Chromosomal abnormalities among children born with conotronicalcardiac defects

Conotruncal heart abnormalities are related to division or faultyconotruncal septation of the solitary primitive heart-tube thisdivision causes two outflow tracts, the two outflow tracts are causedby two swelling fusion that comes from truncal region. Recently therehave been increasingly awareness of chromosome abnormality andconotruncal association4.

In a study conducted in California to describe the relationshipbetween conotruncal heart malformation and chromosomes abnormalities.The result indicated that from a population of 974,579infants/fetuses approximately 622 infant/fetuses were confirmedaortopulmonary septation defect. 5% of the 622 suffered fromchromosomal abnormalities4.

Distinctive demography, biology and outcome of acute myeloidleukemia and myelodysplastic syndrome in children with Down syndrome:children`s cancer group studies 2861 and 2891.

According to result of studies carried in the recent past on acuteleukemia (AML), for children with the Down syndrome children withthis condition have more megakaryoblastic leukemia and experiencesfavorable outcome compared to other children. Further research onthis was conducted by a group called children cancer group. Which,investigated biology and demography and children with or without DSresponse in MDS and AML5. The studies assessed theinduction therapy timing and contrasted marrow transplantation withpost remission chemotherapy in 1,206 children. From this number, 9.8%had down syndrome. The patient with down syndrome was young with lowplatelet and white blood cells.

The results were that the a child with down syndrome and AML his orher AML were biologically and demographically different that ofchildren without the down syndrome5.

Short-term memory and vocabulary development in children with Downsyndrome and children with specific language impairment

In a study conducted on this, a comparison between developments ofvisuospatial short-term memory and verbal development and vocabularyfor kids with DS condition, kids with specific impairment in languageand normal developing children as a control group. Over a period ofone year all participant completed test receptive and expressivevocabulary tasks, visuospatial short-term memory, verbal short-termmemory6. In verbal short-term memory similarities wasseen. Children specific language impairment had problems withvisual-spatial short-term memory compared to other groups. The threegroups performed almost the same in visuo-spartial short-term memoryperformance. The clinical groups performed the same in vocabularywhile as the normal developing children performed better than therest in vocabulary.

Sperm aneuploidy in fathers of children with paternally andmaternally inherited Klinefelter syndrome. This study wasconducted with the aim of finding out the association betweenfathering kids with trisomy and aneuploidy sperm frequency. Thefindings of this study were that children fathered by fathers withhigher XY sperm aneuploid frequencies had Klinefelter syndrome7.

Growth curve for girls with Turner syndrome

In study conducted by Lyon, Preece and Grant to see whether theturner syndrome causes increase in height in girls with thiscondition. The growth chart was prepared with data obtained fromEuropean patient. Retrospective data was used to evaluate the girl`sheight. Result showed that it was possible to calculate the girlsheight at adulthood8. Furthermore from this studyoestrogen which is used to increase the girl`s growth had no effecton their height.

Angelman syndrome

This is a rare genetic condition that causes delayed development,impairs the speech severely, causes intellectual disability andmovement problems this is so because it impinge on the nervoussystem. In children this disease causes epilepsy, microcephaly thatis small head size. Such children are always happy and have a problemsleeping9.

Angelman syndrome: consensus for diagnostic criteria.

In a study conducted in the year 2005on Angelman syndrome on aconsensus statement which was published in 1995 with the aim ofgiving a summary of the angelman syndrome salient clinical feature inorder to aid the clinician to make accurate diagnosis and timely too.The findings showed that a review of the consensus was needed inorder to come up with a method that would be effective in helping theclinicians to carry out diagnostic test and have all the support theymay need10. In addition to this, the study suggested thatangelman syndrome phenotypical characteristics ought to be known inadvance before any testing can be conducted.

Cited Reference

  1. Johannes Nielsen and Mogen Wohlert, (1991). Chromosome abnormalities found amoung 34910 newborn children: results from 13-year incidence study in Arhus, Denmark. Birth defects Orig. Artic. Sex, 209-223.

  1. Lammer EJ1, Chak JS, Iovannisci DM, Schultz K, Osoegawa K, Yang W, Carmichael SL, Shaw GM. (2009). Chromosomal abnormalities among children born with conotruncal cardiac defects. Birth Defects Res A Clin Mol Teratol.85(1):30-5.

  1. Lammer, E. J., Chak, J. S., Iovannisci, D. M., Schultz, K., Osoegawa, K., Yang, W., Carmichael, S. L. and Shaw, G. M. (2009), Chromosomal abnormalities among children born with conotruncal cardiac defects. Birth Defects Research Part A: Clinical and Molecular Teratology, 85:&nbsp30–35. doi:&nbsp10.1002/bdra.20541

  1. Lange BJ, Kobrinsky N, Barnard DR, Arthur DC, Buckley JD, Howells WB, Gold S, Sanders J, Neudorf S, Smith FO, Woods WG. Distinctive demography, biology and outcome of acute myeloid leukemia and myelodysplastic syndrome in children with Down syndrome: children`s cancer group studies 2861 and 2891. Blood. 1998 Jan 1591(2):608-15.

  1. Hick RF1, Botting N, Conti-Ramsden G. (2005). Short-term memory and vocabulary development in children with Down syndrome and children with specific language impairment. Development Medicine &amp Child Neurology, 47, 532-538.

  1. Eskenazi B, Wyrobek AJ, Kidd SA Lowe X, Moore D, Weisiger K, Aylstock M. (2002) Sperm anevploidy in fathers of children with paternally and maternally inherited Klinefelter syndrome. Hum Reprod.

  1. Bareille P1, Massarano AA, Stanhope R. (1997). Final height outcome in girls with Turner syndrome treated with a combination of low dose oestrogen and oxandrolone. National Center for Biotechnology Information, U.S. National Library of Medicine. internet source

  1. Dan, B. (2007). Angelman syndrome. London: Mac Keith Press

  1. García Ramírez M1, Csanyi B, Martínez Antón J, Delgado Marqués M, Bauzano Poley E. (2008). Genetic and clinical diagnosis of Angelman syndrome. Case Reviews. An Pediatr (Barc). 2008 Sep69(3):232-8

  1. García Ramírez M1, Csanyi B, Martínez Antón J, Delgado Marqués M, Bauzano Poley E. (2008). Genetic and clinical diagnosis of Angelman syndrome. Case Reviews. An Pediatr (Barc). 2008 Sep69(3):232-8