I-Chromosomes, i-Trisomy Types, i-Heredity, ne-Down Syndrome
I-Down syndrome ibangelwa inombolo ye-21 ye-chromosome, kodwa oko kuthetha ukuthini ngempela? Yintoni eyenza i-chromosome eyongezelelweyo? Ngaba i-Down syndrome ingaba nefa? Ukuqonda ngokwenene oko kubangela i-Down syndrome, kufuneka ube nokuqonda ngokucacileyo ukuba yeyiphi i-chromosomes, kunye noko bayenzayo. Ukuqonda i-genetics ye-Down syndrome kuyinselele, kodwa ukuthatha ixesha lokugaya le ngcaciso kunokuqinisekisa ukuba bobabini ngabazali-abanokukhathazeka ngexesha lokukhulelwa, kunye nabazali abanomntwana abane-Down syndrome abazibuza loo mbuzo onzima: "Ngoba?"
Ukuqonda i-Genetics
Iipakethi zeeNkcukacha zeGenesis
Indlela elula yokucinga ngama- chromosomes njengephakheji yolwazi lwezofuzo. Umzimba womntu wenziwe ngeentlobo ezahlukeneyo zeeseli kwaye ngaphakathi nganye kweeseli, kwi-nucleus, ziyizifo zethu zobomi. AmaGenesis yiiyunithi zelifa ezidlulileyo ukusuka kwesinye isizukulwana ukuya kwesinye. Zifumaneka kuyo yonke iseli yemizimba yethu kwaye zinika imiyalelo yesakhiwo ngasinye kunye nomsebenzi womzimba wethu. Abantu baneendawo ezingama-25 000 ezahlukeneyo. Kunokuba ibe nama-25,000 ajikeleza ngaphakathi kweeseli ngokwabo, iigesi zethu zitholakale okanye zifakwe kwiipromosomes kunjengeeparele entanyeni.
IGenesis
Iimvelaphi zenziwe nge-DNA ekhoyo i-molecule eyenziwe ngamakhemikhali amane ahlukeneyo abizwa ngokuba yiziseko eziqhelekileyo ezibizwa ngokuba yi-initials-A ye-adenine, T ye-thymine, G ye-guanine kunye neC for cytosine. Ezi ziseko ezi-4 zenza "ikhowudi yezofuzo" -uhlobo oluthile lweelfabethi.
Iimvelaphi zenziwe ngamacandelo amancinci e-DNA kwaye ezi jeni zifumaneka kuma-chromosomes. Ukuba ucinga ngeesiseko njenge-alfabhethi, ngoko iiglefu zinokucingwa njengezivakalisi. Isivakalisi ngasinye (okanye imfuza) inikeza umyalelo othile wemibutho yethu. Elinye ibini lemizimba lingatsho ukuba yintoni umbala amehlo ethu aya kubakho ngelixa elinye inhlanganisela yamajethi ingachaza indlela encinci yomnwe wethu omncinci!
Xa izazinzulu zifuna ukubhekisela kuzo zonke iizakhi zethu zegesi, zibiza ngokuthi "i-genome."
Ama-Chromosomes
Ama-Chromosomes, kunye neendlovu ezikuzo, ziza zibini. Abantu banama-chromosomes angama-46 ahlelwe ngama-23 amabini. Iimbini ze-22 zokuqala ze-chromosomes zibizwa ngokuthi "i- autosomes " kwaye zibalwa 1 ukuya ku-22, ukusuka kwi-big to smallest. Ibini le-23 libizwa ngokuthi "i- chromosomes yesini " kwaye iqukethe i-X kunye ne-Y kwindoda kunye ne-X i-chromosomes kubafazi. I-Chromosomes iyakubonwa phantsi kwe-microscope kodwa i-geni nganye ekhona kuyo ayikwazi. Uvavanyo oluvumela i-chromosomes ukuba ibonwe (kwaye ibalwe) luvavanyo lwekaryotype ,
Trisomy
Uninzi lwabantu lunama-chromosomes angama-46 okanye ama-23 amabini ama-chromosomes. Abantu abane-Down syndrome baneenombolo ezingaphezulu kwe-chromosome ezingama-47 ezipheleleyo ezingama-47 ama-chromosomes. Le meko ibizwa nangokuthi " iTrisomy 21. " I-Trisomy ivela kwiLatini igama elithi "tri" elithetha ezintathu kunye "nezinye" ezithetha umzimba kwaye zibhekisela kuma-chromosomes. Abantu abane-trisomy 21 banemizimba emithathu ye-21, okanye i-chromosomes yeenombolo ezintathu.
Ngenxa yokuba i-chromosomes iiphakheji zolwazi lwezofuzo kwaye ziqulethe zonke iigeni okanye imiyalelo, abantu abane-Down syndrome ngokwenene baneekopi ezintathu zazo zonke iizakhi ezikhoyo kwi-chromosome 21.
Kuqikelelwa ukuba kukho amagciwane angama-400 kwi-chromosome 21. Ngoko-ke, abantu abane-Down syndrome baneemigaqo engaphezulu kwama-400. Nangona ukuba imiyalelo eyongezelelweyo ibonakala ngathi kufanele ukuba yinto entle, ngokwenene kufana nokongeza izithako ezingaphezulu kwi-recipe. Uza kufumana isidlo esisisiseko (umzimba womntu) kodwa ifom kunye nomsebenzi uhlukile.
Ukongeza kwi-trisomy 21, kukho ezinye i-trisomi zabantu . I-Down syndrome, okanye i-trisomy 21 yiyona nto eqhelekileyo ye-autosomal trisomy, kodwa iintsana ezine-trisomy 13 (i-Patau syndrome) kunye ne-trisomy 18 (i-Edward's syndrome) ngamanye amaxesha inokuhlala ikhulelwe. Ukulindela ubomi kubantwana abanamanye ama-trisomi aphantsi kwi-Down syndrome.
Ukuqhathaniswa ne-trisomy 15, 16, kunye ne-22 ngokuqhelekileyo kuphelelwa ekuphumuleni. Ama-trismi kwenye i-chromosomes ayibonakali kwaye ayedla ngokuphela kokukhulelwa kwangaphambili ngaphambi kokuvavanywa.
Isondo se-chromosome yesini esichaphazela i-X kunye nee-chromosomes ziqhelekile, umzekelo, i- Klinefelter's syndrome (i-XXY) iqikelelwa ukuba ifuthe 1 kwi-1000 yamadoda.
Ngokuphambene neetrismi, ezinye i-chromosome ezingaqhelekanga kwiintsana zibangelwa inani elinciphile lama-chromosomes, i-monosomy. Umzekelo ngu-Turner's syndrome apho i-chromosome enye yesondo ilahlekile, 45 X0 okanye i-monosomy X.
Izizathu zeTrisomy
I-Trisomy ye-chromosome ethile yiphumo lokungahambi kakuhle kwindoda okanye iqanda ngaphambi kokukhulelwe. Ngokuqhelekileyo i-chromsomes iyakhuphuka kwaye ihlukaniswe ngokukhawuleza ngexesha lokwahlukana. Ngama-trismi, zombini i-chromosomes iya kwelinye iqanda, kunokuba xa lidibene ne-sperm (xa iqanda ne-sperm lidibanisa), kukho ezintathu.
Akukho nto into yokuba umntu angayenza ukukhusela i-trisomy, kwaye akukho nto umntu angayenza ukuze enze i-trisomy. Yinto eyenzeka ngengozi ngaphambi kokuba ukhulelwe (nge-trisomy epheleleyo) kwiqanda okanye kwisidoda. Asazi oko kubangela ukuba i-trisomy ivele, nangona siyazi ezinye izinto ezinobungozi obangela umngcipheko wale nto eyenzekayo.
Iintlobo zeTrisomy 21
Kukho iintlobo ezahlukeneyo ze-trisomy 21:
Gcwalisa i-Trisomy 21 - Gcwalisa i-trisomy 21 inoxanduva malunga neepesenti ezingama-95 ze-Down syndrome. Njengoko kuphawuliwe ngasentla, xa i-chromosomes idibanisa ukuzahlula (ukudala amaqanda okanye i-sperm kwinkqubo ebizwa ngokuthi i-meiosis), esikhundleni se-chromosome ezimbini eyahlukana ukuya kumaqanda ahlukeneyo, zombini i-chromosomes iya kwelinye iqanda kwaye akukho ma-chromosomes eya kwenye. Oku kubizwa kungekhona ukudibanisa.
I-Transferation Trisomy 21 - I- trisomy ye-Transferation 21 ivela kwimizuzu engama-4 yeintsana ezine-Down syndrome. Kwi-translocation kukho iikopi ezimbini ze-chromosome 21, kodwa izinto ezongezelelweyo ukusuka kwi-chromosome yesithathu e-21 iqhotyoshelweyo (ihanjiswe kwenye) enye i-chromosome. Olu hlobo lwe-Down syndrome lwenzeka ngaphambi okanye emva kokukhulelwa, kwaye yindlela apho ngezinye ixesha idluliselwa khona (ifa.).
UMoses Trisomy 21 - Iyona nto iqhelekileyo ye-Down syndrome, i-mosaic I-Down syndrome ivela xa ezinye iiseli zinekhophi eyongezelelweyo ye-chromosome 21. Le fomu ye-trisomy iyenzeka emva kokukhulelwa, kodwa ayiyazi ukuba kutheni kwenzeka. Nangona abantu abane-trisomy epheleleyo 21 kunye ne-translocation 21 bafana, i-trisomy mosaic 21 ihluke ngokuxhomekeka kwinani leeseli ezine-chromosome eyongezelelweyo.
Ngaba I-Down Syndrome Ingaba Ifa?
Ngokuqhelekileyo, i-Down syndrome 'ayizukuzuzwa' kodwa ingadluliselwa kubazali ukuya kubantwana abane-transrisation trisomy 21 (elandisa malunga neepesenti ezine zabantu abane-Down syndrome.) Kwingxenye yesithathu yabantu abane-transrisation trisomy 21, i-trisomy (ezimbini i-chromosome 21 kunye ne-chromosome eyongezelelweyo engu-21 eqhotyoshelwe kwenye i-chromosome) izuzwe ngumzali. Umngcipheko womntu onokutshatyalaliswa kwe-trisomy 21 ukudlula kwimeko kumntwana kuba ngama-10 ukuya kwe-15 ekhulwini kubafazi kunye neepesenti ezintathu zamadoda.
Ekubeni ukutshintshela i-trisomy 21 kuphela kubhalisa malunga neepesenti ezine zabantu abane-Down syndrome, ngaphantsi kwepesenti enye yamatyala aya kuthathwa njengelifa.
Ukuba umntwana okanye umntu omdala one-Down syndrome ukhulelwa, umngcipheko we-Down syndrome okanye ukhubazeko olusakhulayo kumntwana luphakathi kwama-35 no-50 ekhulwini. Ekubeni abantu abaninzi abane-Down syndrome bangakhokelela kwimpilo ephezulu yokusebenza, kwaye babe nolwazi kunye nolwalamano njengabo abangenayo i-Down syndrome, oku kuyingozi ukuba ilinganiswe malunga neenzuzo ngabazali-ukuba babe nengqiqo. Phantse ama-50 ekhulwini kwabasetyhini abane-Down syndrome bayakwazi ukukhulelwa.
Izinto zobungozi
Uninzi lwabazali abanomntwana one-Down syndrome abanalo nayiphi na ingozi eyaziwayo. Kwakhona kubalulekile ukuba uqaphele ukuba, ngoku kubekho, akukho ndlela yokuphila okanye ingozi yokusingqongileyo ye-Down syndrome . Ngamanye amagama, ngaphandle kweyonyuka kunye nobudala bomama (kwaye nangona kunjalo a baninzi abafazi abanabantwana abane-Down syndrome bancinci) akukho nto inokukunceda ukuqikelela okanye ukuthintela ukuba nomntwana one-Down syndrome.
Umngcipheko woMdala kunye ne-Down Syndrome
Nangona i-trisomi iyakwenzeka kubantu bakuphi na ubudala, kukho ubudlelwane phakathi kobudala bomama kunye nethuba lokuba nomntwana one-trisomy. Inhlangano yinto nje yenzululwazi yekhonkco. Umbutho awukho isizathu. Le ngongoma ebalulekileyo, kuba abantu bahlala bephantsi kweenkolelo eziphosakeleyo ukuba iminyaka yobudala ibangela i-Down syndrome. Oku akunjalo. Asazi oko kubangela ukuba i-trismi ivele. Siyazi nje ukuba njengabasetyhini bakhula, ingozi yokukhulelwa kunye nokwanda kwe-trisomy.
Nangona kukho unxibelelwano phakathi kobudala bomama kunye nentsholongwane yezifo, ininzi iintsana ezine-Down syndrome zizalelwa oomama abangaphantsi kweminyaka engama-35. Oku kubangelwa ukuba kukho incincikazikazi encinane inabantwana. Enyanisweni, iipesenti ezingama-80 zezantsana ezizalwa nge-Down syndrome zizalelwa kwabasetyhini abangaphantsi kwama-35 kwaye ubudala bomama wengane ene-Down syndrome iminyaka engama-28. Ngokubanzi, amathuba okuba ngumntwana ongaphantsi kweminyaka engama-30 abelethe umntwana one-Down syndrome ungaphantsi kwe-1: 1000. Umngcipheko ukwanda njengoko umfazi ekhulile, kunye nesiganeko malunga ne-1: 112 kwiminyaka engama-40 ubudala. Nangona kunjalo, oku kusekho ngaphantsi kwepesenti enye yabasetyhini abakhulelweyo abaneminyaka engama-40.
Ishati efanisa iminyaka yobudala kwisifo se-Down syndrome iyafumaneka, kodwa kubalulekile ukuqaphela abafazi ngaphambi kokuba bajonge kule tshathi. Qinisekisa ukukhumbula ukuba ininzi yabasetyhini abakhulelweyo abangaphezu kweminyaka engama-35 banabantwana abangenayo i-Down syndrome.
Amanye amabhinqa angaphezu kweminyaka engama-35 (okanye ngezinye izinto ezinobungozi) angakhetha ukwenza i-amniocentesis ukuba ikhusele i-Down syndrome okanye ezinye iimvavanyo zokubeleka. Isigqibo sokuba ingaba le mivavanyo ingeyomntu siqu okanye ingafanelekiyo, kwaye kufuneka iyenziwe ngoncedo lwe-genetic counseling. I-American College ye-Obstetrics kunye ne-Gynecology icebisa ukuba bonke abafazi banikezelwe uvavanyo lwe-Down syndrome. Abanye besetyhini bakhetha ukuba olu vavanyo lwenziwa kokubili ukuqinisekiswa kunye nokukwazi ukucwangcisa phambili, ngelixa zikho izizathu ezicacileyo zokuba kutheni abafazi bekhetha ukungenzi iimvavanyo zangaphantsi.
Ingozi yobudala be-Down and Syndrome
Kuqikelelwa ukuba i-chromosome eyongezelelweyo kwi-Down syndrome ivela kumama ininzi yexesha kunye nobawo (isisu) kuphela iipesenti ezine zexesha. Nangona ukukhula kweminyaka yobubele kuhambelana nobungozi be-Down syndrome, okufanayo akuyiyo inkqubela yokuzala abantwana ngenxa nje yokuba amaqanda adala, kodwa i-sperm iqhutshwa rhoqo kangangokuthi idla nje iiveki ezimbalwa. Noko ke, zikhona izimo zofuzo ngaphandle kwe-Down syndrome ezixhomekeke kwiminyaka yobudala, njengo- achondroplasia (dwarfism) kunye ne-Marfan syndrome.
Uphando kunye nekamva
Ngentetho malunga neProjekthi ye-Human Genome kunye ne- generapy therapy abazali baye bacela umbuzo omhle kakhulu: "Kutheni inkunkuma yegciwane ingasetyenziselwa ukulungisa i-genetic ejwayelekile kwi-Down syndrome?" Ngelishwa, ukuqonda kwethu imfuza kungekho. Yiyiphi imithi yonyango inokukunceda ubuncinane kwixa elizayo, isebenzisana ne-gene engafanelekanga. Isimo esibangelwa imfuza engaphezu kweyodwa, makungabikho nto i-chromosome yonke iya kuba nzima ukuyiphatha nge-gene treatment. Ngenxa yoko abaphandi bajonga oko kunokwenzeka nge-epigenetic ubunjineli-epigenetics yintsimi ejongene neentetho (ukubonakaliswa kweeklinikhi) zegesi kunokuba izakhi zofuzo ngokwazo.
Oko kwathiwa, ulawulo lwabantwana abazalwa nge-Down syndrome luye lwaphucuka ngokuphawulekayo kwiminyaka embalwa edlulileyo.
Okukwintsusa
Umgca wokuqala kukuba siyazi ukuba kukho umnxibelelwano okanye umbutho phakathi kobudala bomama kunye nomngcipheko wokuba nomntwana one-trisomy efana ne-Down's syndrome, kodwa akukho mntu owaziyo isizathu esithile se-trismi.
Imithombo:
Dekker, A., De Deyn, P., kunye neM.Rots. I-Epigenetics: I-Key Neglected Key to Minimize i-Learning and Memory Deficits kwi-Down Syndrome. I-neuroscience kunye neengcebiso ze-Biobehavioral . 2914. 45: 72-84.
I-Mentis, A., i-Epigenomic Engineering ye-Down Synrome. I-neuroscience kunye neengcebiso ze-Biobehavioral . 2016. 71: 323-327.