Chromosomes, Trisomy Types, Heredity, uye Down Syndrome
Down syndrome inokonzerwa nhamba yepamusoro 21 chromosome, asi izvi zvinorevei chaizvoizvo? Chii chinokonzera imwe chromosome? Can Down syndrome inogona kupiwa nhaka here? Kunyatsonzwisisa chinokonzera Down syndrome, unofanirwa kunyatsonzwisisa kuti chromosomes chii, uye zvavanoita. Kunzwisisa ruzivo rweArt syndrome kwakaoma, asi kutora nguva yekuchera ruzivo urwu kunogona kuvimbisa kuvabereki vose-kuva-vane vane hanya panguva yekuzvitakura, uye vabereki vane mwana ane Down syndrome vanozvibvunza mubvunzo wakaoma iwoyo: "Sei?"
Kunzwisisa Genetics
Packages of Genetic Information
Nzira iri nyore yekufunga nezvekromosomes yakafanana nemaphaketeni ekuzivikanwa kwei genetic. Muviri womunhu unoumbwa nemhando dzakasiyana-siyana dzemasero uye mukati memumwe wemasero aya, mumusana, ndiyo majeni edu. Zvitema zviyero zvefa rinopfuudzwa kubva kune rimwe chizvarwa kuenda kune rimwe. Inowanikwa mumasero ose emitumbi yedu uye inopa mirayiridzo yehutano hwose uye basa remuviri wedu. Vanhu vane makore anenge 25 000 akasiyana-siyana. Panzvimbo yekuva ne 25 000 yose inoputira mukati memasero ega ega, majini edu aripo kana akaiswa pamakromosomes pane kunge maparera pamutsipa.
Genesisi
Zvitema zvakagadzirwa neDNA iyo inonzi molecule inoumbwa nemakemikari mana akasiyana-siyana anonzi mabhesi, ayo anowanzotumidzwa nematangiro awo-A yeAdenine, T ye thymine, G ye guanine uye C ye cytosine. Aya mabheji mana anoumba "genetic code" -hutsika yehufabheti.
Zvitsva zvinoumbwa nezvikamu zviduku zveDNA uye majeni aya anowanika pama chromosomes. Kana iwe uchifunga nezvezvigadziro searfabheti, mazamu ezvo anogona kuonekwa semitsutso. Mutsara wega wega (kana geni) unopa murairo chaiwo wemitumbi yedu. Mamwe mapeji emagetsi angatiudza mavara maziso edu achava akadini apo imwe mazana emagetsi angatiudza kuti duku duku yedu inofanira kunge iri sei!
Apo masayendisiti anoda kutarisa kune ose emajini edu pamwe chete, vanozviti "genome."
Chromosomes
Chromosomes, pamwe chete nemajeni ari pavari, pindai vaviri. Vanhu vane 46 ma chromosomes akagadzirirwa muna 23 mapaundi. Makore makumi maviri nemasere emakromosomes anonzi " autosomes " uye anoverengwa 1 kusvika ku22, kubva kuvakuru kusvika kuduku. Iviri yechipiri inonzi " chromosomes zvepabonde " uye inosanganisira X uye Y mune varume uye maviri X chromosomes muvakadzi. Chromosomes inogona kuonekwa pasi pekroscope asi majini ega ari pavari haagoni. Chiyero chinobvumira ma chromosomes kuti ave visualized (uye akaverengwa) chirongwa chekaryotype ,
Trisomy
Vanhu vazhinji vane chromosomes 46 kana mapaundi makumi maviri nemaviri emakromosomes. Vanhu vane Down syndrome vane nhamba yepamusoro 21 yechromosome ye 47 kromosomes. Izvi zvinonziwo " Trisomy 21. " Trisomy inobva mushoko rechiLatini rokuti "tri" zvinoreva zvitatu uye "zvimwe" zvinoreva muviri uye zvinoreva ma chromosomes. Vanhu vane trisomy 21 vane miviri mitatu 21, kana matatu nhamba 21 chromosomes.
Nokuti ma kromosomes ndiwo mapeji ezvinyorwa zvemashoko uye ane majeni edu ose kana mirayiridzo, vanhu vane Down syndrome vane zviro zvitatu zvejeni zvose zviri pa chromosome 21.
Inofungidzirwa kuti pane mageneji mazana mana emakromosome 21. Saka zvakananga, vanhu vane Down syndrome vane mazano anopfuura 400. Kunyange zvazvo uine mirayiridzo yakawanda inonzwika sekuti inofanira kunge iri chinhu chakanaka, chaizvoizvo kufanana kuwedzera zvimwe zvigadzirwa kune recipe. Iwe uchave uchingowana kudya kwakafanana (muviri wemunhu) asi maitiro uye basa zvakasiyana.
Mukuwedzera kune trisomy 21, kune mamwe maitiro evanhu . Down syndrome, kana trisomy 21 ndiyo inowanzojairika yerotomy, asi vana vane trisomy 13 (Patau syndrome) uye trisomy 18 (Edward's syndrome) dzimwe nguva inogona kupona pamuviri. Chirongwa chehupenyu chevana vane mamwe matambudziko anokonzerwa neArt syndrome.
Kuberekwa ne trisomy 15, 16, uye 22 kazhinji kunopera mukuparara. Matambudziko mune mamwe ma chromosomes haawanzoonekwi uye anowanzoguma mumuchembere kwazvo pamuviri musikana asati aongorora.
Zvepabonde chromosome trisomies dzinosanganisira X uye Y chromosomes zvakajairika, semuenzaniso, Klinefelter's syndrome (XXY) inofungidzirwa kuchinja 1 mu1000 varume.
Kusiyana nematambudziko, mamwe maitiro echromosome mucheche anokonzerwa nekuderera kwenhamba yekromosomes, 'monosomy'. Muenzaniso ndewe Turner's syndrome mune imwe chromosome yepabonde inoshayikwa, 45 X0 kana kusagadzikana X.
Zvinokonzera Trisomy
Trisomy yekromosome yakadaro inoguma nekusvibiswa mumunhu kana mazai asati aita pamuviri. Kazhinji iyo chromsomes inokwira uye inoparadzaniswa zvakafanana panguva yekugovana. Nezvipembenene, ma chromosomes anoenda kune rimwe dza, saka kupfuura apo paine kusanganiswa nehuta (apo egg uye mbeu inoungana), pane zvitatu.
Hapana zvachose icho munhu angagona kuita kudzivirira trisomy, uye hapana chinhu icho munhu angaita kuti atadze trisomy. Izvo zviitiko zvinowanzoitika zvinotanga kuitika musati mimba (mune trisomi yakakwana) mune yei kana chirume. Hatisingazivi chinokonzera trisomi kuitika, kunyange tichiziva nezveimwe ngozi inowedzera iyo inowedzera dambudziko rekuitika kweizvi.
Mhando dzeTrisomy 21
Kune zvitatu zvakasiyana siyana zve trisomy 21:
Zvose Trisomy 21 - Complete trisomy 21 inobatanidzwa inenge 95 muzana yeArt syndrome. Sezvakataurwa pamusoro apa, kana ma-chromosomes akasimuka kuti aparadzanise (kuti atange mazai kana kuti mbeu mumushandisi unonzi meiosis), panzvimbo yekromosome mbiri iri kuparadzanisa kuenda kune mazai akasiyana, ma chromosomes anoenda kune rimwe dza uye hapana ma chromosomes kuenda kune rimwe. Izvi zvinonzi kwete-disjunction.
Translocation Trisomy 21 - Translocation trisomy 21 inowanikwa mumativi anenge makumi mana kubva kuvana vane Down syndrome. Mune shanduko pane makopi maviri e-chromosome 21, asi zvimwe zvinyorwa kubva kune chromosome yechitatu yechipiri yakabatanidzwa (kutamirwa kune) imwe chromosome. Ikoko chirwere che Down syndrome chinogona kuitika mushure mekunge kana mushure mokumbwa pamuviri, uye ndiyo iyo iyo dzimwe nguva inogona kupedzwa (yakagara nhaka.)
Mosaic Trisomy 21 - Zvisinganyanyozivikanwi zveA Down syndrome, mosaic Down syndrome inowanikwa apo mamwe masero ega ane kopi yekare yekromosome 21. Iyi fomu yeTrisomy inoitika mushure mekuberekwa, asi hazvizivikanwi nei ichiitika. Kunyange zvazvo vanhu vane trisomy yakakwana 21 uye kutumirwa 21 kwakafanana, trisomy mosaic 21 inopesana zvichienderana nenhamba yemasero ane kromosome yakawedzerwa.
Kunogona Kuchinja Syndrome Ive Yakagamuchirwa Here?
Kazhinji, Down syndrome haisi "nhaka" asi inogona kutapudzwa kubva kuvabereki kuenda kune vana vane trisomy 21 (iyo inofanirwa nevanenge vana 4 muzana yevanhu vane Down syndrome.) Munenge chikamu chetatu chevanhu vane transrisation trisomy 21, trisomy (maviri kromosome 21's pamwe chete nekromosome yakawedzerwa 21 yakabatanidzwa kune imwe chromosome) inotora nhaka kubva kumubereki.Ichiitiko kune mumwe munhu ane chirwere chekutengesa trisomy 21 kupfuudza mumamiriro ezvinhu kumwana anenge anenge 10 kusvika ku15 muzana yevakadzi uye vatatu muzana yevarume.
Sezvo kutumirwa kwetrisomy 21 kunongoratidzira kwemazana mana kubva muzana yevanhu vane Down syndrome, pasi pezana rimwe rematambudziko raizoonekwa sefa.
Kana mwana kana munhu mukuru ane Down syndrome anova nepamuviri, njodzi yeA Down syndrome kana zvimwe zvirwere zvinokurudzira mumwana iri pakati pe35 ne50 muzana. Sezvo vanhu vakawanda vane Down syndrome vanogona kutungamira hupenyu hwehupenyu hwakanyanya, uye vanoona rudo uye hukama sezvinoitwa nevaya vasina Down syndrome, iyi ingozi inoda kuyerwa neyezvibereko nevabereki-kuva-inofungisisa. Inenge 50 muzana yevakadzi vane Down syndrome vanogona kutora pamuviri.
Risk Factors
Vabereki vakawanda vane mwana ane Down syndrome havana chero njodzi dzinozivikanwa. Zvakakoshawo kuziva kuti, kusvika panguva ino, hapana mararamiro ehupenyu kana zviitiko zvekuchengetedzwa kwemamiriro eDave syndrome . Mune mamwe mazwi, kunze kwekuwedzera kwezera remakore (uye asi vakadzi vakawanda vane vana vane Down syndrome vari vaduku) hapana chinhu chinogona kubatsira kutaurira kana kudzivirira kuva nemwana ane Down syndrome.
Maternal Age uye Down Syndrome Njodzi
Kunyange zvazvo matambudziko anogona kuitika kune vanhu vezera ripi neripi, pane sangano pakati pezera remadzimai uye mukana wokuva nemwana ane trisomy. Kushamwaridzana ishoko rezvesayenzi chete yekubatanidza. Ushamwari haisi chikonzero. Iyi iyi pfungwa inokosha, nokuti vanhu vanowanzova pasi pekutenda kusina kururama kwekuti makore ekuberekwa anokonzera Down syndrome. Izvi hazvisi chokwadi. Hatisingazivi chii chinoita kuti trisomi zviitike. Isu tinoziva chete kuti sezvo vakadzi vari kukwegura, njodzi yekubata pamuviri neTrisomy inowedzera.
Kunyange zvazvo kune hukama pakati pemakore ekuberekwa uye kuitika kwemazuva ano, vana vakawanda vane Down syndrome vanoberekerwa vanaamai vari pasi pemakore makumi matatu nemashanu. Izvi zvinokonzerwa nokuti kune vakadzi vaduku vakawanda vane vana. Kutaura zvazviri, 80 muzana yevana vakaberekwa neArt syndrome vanoberekerwa vakadzi vasingapfuuri makumi matatu nemakumi matatu uye muvhareji yemakore emwana wemwana ane Down syndrome makore 28. Kakawanda, mikana yemukadzi ari pasi pemakore makumi matatu ekuberekerwa mwana ane Down syndrome iri pasi pe1: 1000. Ngozi inowedzera sezvo mukadzi akura, ane chiitiko che1: 112 pazera remakore makumi mana. Zvisinei, ichi chichiri pasi pezana kubva muzana yevakadzi vanotora pamuviri pazera remakore makumi mana.
Chati ichienzanisa nemakore ekuberekwa kusvika kuArt syndrome ngozi inowanika, asi zvakakosha kuchenjerera vakadzi vasati vatarisa chati ino. Iva nechokwadi chekuchengeta mupfungwa kuti huwandu hwevakadzi vanotora pamuviri pamusoro pemakore makumi matatu nemaviri vane vana vasina Down syndrome.
Vamwe vakadzi vanopfuura makore makumi matatu (kana kuti nezvimwe zvipingamupinyi) vanogona kusarudza kuva neamniocentesis kuti vadzivirire Down syndrome kana zvimwe zvirwere zvepabonde. Chisarudzo chingave kana kuti kwete kuti izvi zviongorwe zvakanyanya, uye zvinofanira kuitwa nekubatsirwa kwehutano hwekuberekwa. IAmerican College of Obstetrics uye Gynecology inokurudzira kuti vakadzi vose vabvumirwe kuongorora zvirwere zveTrans syndrome. Vamwe vakadzi vanosarudza kuti kuedza uku kuitike zvose kuti vatsigire uye vave nekwanisi kuronga mberi, asi pane zvikonzero zvakajeka nei vakadzi vanosarudza kusaita zvirwere zvepabonde zvakare.
Paternal Age uye Down Syndrome Njodzi
Zvinofungidzirwa kuti chromosome yakawedzerwa mu Down syndrome inobva kuna amai nguva yakawanda yenguva uye kubva kuna baba (chirume) kane chete muzana yenguva. Kunyange zvazvo kufambira mberi kwemakore ekuberekwa kwakabatana nehutano hweA Down syndrome, zvimwe chetezvo hazvisizvo nekufambira mberi kwezera remadzibaba nekuda kwekuti mazai anokera, asi mbeu inoramba ichigadzirwa kuitira kuti inowanzova masvondo mashomanana chete. Iko kune, zvisinei, maitiro emararamiro kunze kweArt syndrome iyo inobatanidzwa nezera rakakura rebaba, rakadai sechisondroplasia (dwarfism) uye Marfan syndrome.
Kutsvakurudza uye Ramangwana
Nehurukuro pamusoro peHuman Genome Project uye gene therapy vabereki vakabvunza mubvunzo wakanaka kwazvo: "Sei maitiro ejeni asingagoni kushandiswa kugadzirisa maitiro asina kufanana muArt syndrome?" Zvinosuruvarisa, kunzwisisa kwatinoita zviwanikwa hakusipo. Iro gene therapy inogona kubatsira sei zvishoma munguva yemberi iri pedo, iri kushanda pamwe chete nemaitiro ezvakaipa. Chimiro chinokonzerwa nehuwandu humwechete, regai kromosome yose ive yakaoma kubata ne gene therapy. Saka vatsvakurudzi vanotarisa zvinogona kuitika ne epigenetic engineering-epigenetics inzvimbo inotarisa kutaura (kliniki zviratidzo) zvemajini panzvimbo pejeni mavari.
Izvozvo zvakati, kutungamirirwa kwevana vakaberekerwa neArt syndrome kwavandudza zvinoshamisa mumakumi mashoma emakore akapfuura.
Pasi Pasi
Chinonyanya kukosha ndechokuti tinoziva kuti kune hukama kana kusongana pakati pezera remamai uye ngozi yekuwana mwana ane trisomy yakafanana neA Down's syndrome, asi hapana anoziva chikonzero chaicho chematambudziko.
Sources:
Dekker, A., De Deyn, P., uye M. Rots. Epigenetics: The Neglected Key kuti Deredza Kupedza Kudzidza uye Kuyeuka Kwepfungwa muDream Syndrome. Neuroscience uye Biobehavioral Reviews . 2914. 45: 72-84.
Mentis, A., Epigenomic Engineering ye Down Down. Neuroscience uye Biobehavioral Reviews . 2016. 71: 323-327.