Li-chromosomes, Mefuta ea Trisomy, Heredity, le Down Syndrome
Down syndrome e bakoa ke chromosome ea nomoro e eketsehileng ea 21, empa see se hlile se bolela'ng? Ke eng e bakang chromosome e eketsehileng? Na Down syndrome e ka futsa? E le hore u utloisise hantle hore na ke eng e bakang Down syndrome, u lokela ho utloisisa ka botlalo hore na li-chromosome ke eng, le seo li se etsang. Ho utloisisa liphatsa tsa lefutso tsa Down syndrome ho thata, leha ho le joalo ho nka nako ea ho chesa boitsebiso bona hoa khothatsa ho batsoali ba babeli-ba nang le mathata nakong ea bokhachane, le batsoali ba nang le ngoana ea nang le Down syndrome ba ipotsang potso eo e thata: "Hobane'ng?"
Ho utloisisa Genetics
Lipapaka tsa Boitsebiso ba Genetics
Tsela e bonolo ka ho fetisisa ea ho nahana ka li-chromosomes ke liphutheloana tsa boitsebiso ba liphatsa tsa lefutso. 'Mele oa motho o entsoe ka mefuta e fapaneng ea lisele le kahare ho lisele tsena tse ka hare, ke liphatsa tsa rona tsa lefutso. Liphatsa tsa lefutso ke lihlopha tsa lefa tse fetisitsoeng ho tloha molokong o mong ho ea ho o mong. Li teng seleng e 'ngoe le e' ngoe ea 'mele ea rona' me li fana ka litaelo bakeng sa sebopeho se seng le se seng sa 'mele ea rona. Batho ba na le liphatsa tsa lefutso tse ka bang 25 000. Ho e-na le hore batho ba 25 000 ba phunyeletse ka hare ho lisele tsa bona ka bomong, liphatsa tsa lefutso tsa rona li teng kapa li kenngoa ka li-chromosome ho e-na le liperela molaleng.
Genese
Liphatsa tsa lefutso li entsoe ka DNA e leng molek'hule e entsoeng ka lik'hemik'hale tse 'nè tse bitsoang li-base, tse atisang ho boleloa ke li-initials tsa tsona-A bakeng sa adenine, T bakeng sa thymine, G bakeng sa guanine le C bakeng sa cytosine. Li-motheo tsena tse 4 ke "liphatsa tsa lefutso" -e leng mofuta oa alfabeta ea lefutso.
Liphatsa tsa lefutso li entsoe ka likaroloana tse nyenyane tsa DNA 'me liphatsa tsa lefutso tsena li teng ka li-chromosome. Haeba u nahana ka metheo e le li-alphabet, joale liphatsa tsa lefutso li ka nkoa e le lipolelo. Polelo e 'ngoe le e' ngoe (kapa liphatsa tsa lefutso) e fana ka taelo e itseng ea 'mele ea rona Liphatsa tsa lefutso tse peli li ka 'na tsa bolela hore na mahlo a rōna a tla ba joang ha liphatsa tse ling tsa lefutso li ka bolela hore na monoana oa rōna o monyenyane o lokela ho ba o mokae!
Ha bo-rasaense ba batla ho bua ka liphatsa tsa lefutso tsa rona kaofela, ba li bitsa "genome."
Chromosomes
Li-chromosome, hammoho le liphatsa tsa lefutso li fumanehang ho tsona, kena ka bobeli. Batho ba na le li-chromosome tse 46 tse hlophisitsoeng ka lihlopha tse 23. Lihlopha tse 22 tsa pele tsa li-chromosome li bitsoa "li -autosomes " 'me li le 1 ho ea ho 22, ho tloha ho tse kholo ho tse nyenyane. Sehlopha sa bobeli se bitsoa " li-chromosome tsa thobalano " 'me li na le X le Y tse banna le tse peli tsa X chromosomes ka basali. Li-chromosome li ka bonoa tlasa microscope empa liphatsa tsa lefutso tsa motho ka mong li ka sitoa ho li etsa. Teko e lumellang li-chromosome hore e bonngoe (le ho baloa) ke teko ea karyotype ,
Trisomy
Batho ba bangata ba na le li-chromosome tse 46 kapa lihlopha tse 23 tsa li-chromosome. Batho ba nang le Down syndrome ba na le kromosome ea nomoro e eketsehileng ea 21 bakeng sa li-chromosome tse 47. Boemo bona bo boetse bo bitsoa " Trisomy 21. " Trisomy e tsoa lentsoeng la Selatine "tri" le bolelang "boraro" le "tse ling" tse bolelang 'mele' me le bolela li-chromosome. Batho ba nang le trisomy 21 ba na le 'mele e meraro e 21, kapa li-chromosome tse tharo tsa lintlha tse tharo.
Hobane li-chromosome ke liphutheloana tsa boitsebiso ba liphatsa tsa lefutso 'me li na le liphatsa tsa rona tsa lefutso kapa litaelo, batho ba nang le Down syndrome ba na le likopi tse tharo tsa liphatsa tsa lefutso tse teng ka chromosome 21.
Ho hakanngoa hore ho na le liphatsa tsa lefutso tse 400 tsa chromosome 21. Kahoo, ha e le hantle, batho ba nang le Down syndrome ba na le litaelo tse eketsehileng tse 400. Ha ho ntse ho e-na le litaelo tse eketsehileng ho utloahala eka e lokela ho ba ntho e ntle, ha e le hantle e rata ho eketsa lisebelisoa tse eketsehileng ho risepe. U sa ntse u tla ja lijo tse lekaneng ('mele oa motho) empa mokhoa le mosebetsi o fapane.
Ho phaella ho trisomy 21, ho na le lintho tse ling tsa batho . Down syndrome, kapa trisomy 21 ke tismomy e tloaelehileng ka ho fetisisa ea autosomal, empa masea a nang le trisomy 13 (Patau syndrome) le trisomy 18 (Edward's syndrome) ka linako tse ling e ka 'na ea e-ba teng nakong ea bokhachane. Tšepo ea bophelo bakeng sa bana ba nang le mathata ana a mang a tlaase a lekanang le Down syndrome.
Litšebeletso tse nang le trisomy 15, 16, le 22 li atisa ho fela nakong ea ho senyeheloa ke mpa. Li-chromosome tse ling ha li bonahale hangata 'me hangata li fela qetellong ea bokhachane pele ho tlhahlobo e ka etsahala.
Lintho tse kang tsa chromosome tsa thobalano tse amang li-chromosome tsa X le Y li tloaelehile, ka mohlala, Klinefelter's syndrome (XXY) ho hakanngoa hore e ama 1 ho ba batona ba 1000.
Ho fapana le mekhoa e mebe, li-chromosome tse sa tloaelehang ho masea li bakoa ke li-chromosome tse fokotsehileng, 'monosomy'. Mohlala ke lefu la Turner's in which one chromosome ea thobalano e haella, 45 X0 kapa monosomy X.
Mabaka a Trisomy
Trisomy bakeng sa chromosome e itseng ke phello ea ho se utloisisehe ka peō kapa kahe pele a emoloa. Hangata li-chromsomes li phahama 'me li arohane ka mokhoa o ts'oanang nakong ea karohano. Ka li-chromosome, li-chromosome tse peli li ea leheng le le leng, ho feta ha li kopantsoe le peō (ha lehe le peō e kopane), ho na le tse tharo.
Ha ho letho leo motho a ka le etsang ho thibela trisomy, mme ha ho letho leo motho a ka le etsang ho baka trisomy. Ke ketsahalo ea kotsi e hlahang pele ho emoloa (ka trisomy e feletseng) mahe kapa egg. Ha re tsebe hore na ke eng e etsang hore trisomy e hlahe, le hoja re tseba likotsi tse ling tse bakang kotsi ea ho etsahala hona.
Mefuta ea Trisomy 21
Ho na le mefuta e meraro e fapaneng ea trisomy 21:
Trisomy e feletseng 21 - Trisomy e feletseng 21 e ikarabella ho hoo e ka bang karolo ea 95 lekholong ea Down syndrome. Joalokaha ho boletsoe ka holimo, ha li-chromosome li lekana ho arola (ho etsa mahe kapa peō ka mokhoa o bitsoang meiosis), ho e-na le chromosome e 'meli e arohanang ho ea maheeng a fapaneng, li-chromosome tse peli li ea lehong le le leng' me ha ho na li-chromosomes li eang ho e 'ngoe. Sena se bitsoa se seng disjunction.
Trisomy ea Translocation 21 - Trisomy Translocation 21 e hlaha ka hoo e ka bang karolo ea bone lekholong ea masea a nang le Down syndrome. Ka translocation ho na le likopi tse peli tsa chromosome 21, empa lisebelisuoa tse eketsehileng tsa chromosome ea boraro ea 21 e khomaretsoe (e fetiselitsoe ho) e 'ngoe ea chromosome. Mofuta ona oa Down syndrome o ka ba teng pele kapa ka mor'a ho emoloa, 'me ke mofuta oo ka linako tse ling o ka fetisoang (o rua.)
Mosaic Trisomy 21 - Ntho e sa tloaelehang bakeng sa Down syndrome, mosaic Down syndrome e etsahala ha lisele tse ling feela li e-na le kopi e 'ngoe ea chromosome 21. Mofuta ona oa trisomy o hlaha ka mor'a hore o emole, empa ha o tsejoe hore na ke hobane'ng ha o etsahala. Le hoja batho ba nang le trisomy e feletseng 21 le translocation 21 ba tšoana, trisomy ea mosai 21 e fapana ho ea ka palo ea lisele tse nang le chromosome e eketsehileng.
Na Down Syndrome e ka Lefa?
Ka kakaretso, Down syndrome ha e "futsitsoe" empa e ka fetisetsoa ho batsoali ho bana ba nang le ts'oaetso ea trisomy 21 (e leng karolo ea likarolo tse 'nè tsa batho ba nang le Down syndrome.) Hoo e ka bang karolo ea boraro ea batho ba nang le trisomy 21 ea translocation, trisomy (li-chromosome tse peli tsa 21 le li-chromosome tse eketsehileng tse 21 tse amanang le chromosome e 'ngoe) li futsitsoe ho motsoali. Kotsi ea motho ea nang le tranrisation trisomy 21 e fetisetsang boemo ho ngoana ke karolo ea 10 ho ea ho 15 lekholong bakeng sa basali le karolo ea boraro lekholong bakeng sa banna.
Ho tloha ha transmation trisomy 21 e ikarabella feela likarolong tse 'nè tsa batho ba nang le Down syndrome, karolo e ka tlase ho lekholo ea linyeoe e tla nkoa e le lefa.
Haeba ngoana kapa motho e moholo ea nang le Down syndrome a ima, kotsi ea Down syndrome kapa tse ling tsa kholofalo ea tsoelo-pele lesea le pakeng tsa 35 le 50 lekholong. Kaha batho ba bangata ba nang le Down syndrome ba ka phela bophelo bo phahameng haholo, mme ba bona lerato le likamano joaloka ba nang le Down syndrome, hona ke kotsing e lokelang ho lekanyetsoa khahlanong le melemo eo batsoali ba nang le eona-ka mokhoa o nahanang. Basali ba etsang karolo ea 50 lekholong ba nang le Down syndrome ba khona ho ima.
Lintho Tse Kotsing
Batsoali ba bangata ba nang le ngoana ea nang le Down syndrome ha ba na mabaka a kotsi. Hape ke habohlokoa ho hlokomela hore, ho fihlela joale, ha ho na mokhoa o phelang oa bophelo kapa maemo a kotsi a tikoloho bakeng sa Down syndrome . Ka mantsoe a mang, ntle le keketseho ea lilemo tsa bo-'mè (mme basali ba bangata ba nang le bana ba nang le Down syndrome ba sa le monyenyane) ha ho letho le ka thusang ho tseba kapa ho thibela ho ba le ngoana ea nang le Down syndrome.
Bothata ba Bokhachane le Bothata ba Down Syndrome
Le hoja litlhapi li ka etsahala ho batho ba lilemo tsohle, ho na le setsoalle pakeng tsa lilemo tsa 'mè le monyetla oa ho ba le lesea le nang le trisomy. Kamano ke feela lentsoe la saense bakeng sa ho hokahanya. Kamano ha se sesosa. Ena ke ntlha ea bohlokoa, hobane batho ba atisa ho ba le maikutlo a fosahetseng a hore lilemo tsa bokhachane li baka Down syndrome. Sena hase 'nete. Ha re tsebe hore na ke eng e bakang matšoao hore a hlahe. Rea tseba feela hore ha basali ba ntse ba hōla, kotsi ea ho ima le trisomy e eketseha.
Le hoja ho na le kamano pakeng tsa lilemo tsa bokhachane le ketsahalo ea matšoao a kotsi, masea a mangata a nang le Down syndrome a tsoaloa ho bo-'mè ba ka tlase ho lilemo tse 35. Sena se bakoa ke hore ho na le basali ba banyenyane haholoanyane ba nang le masea. Ha e le hantle, masea a 80 lekholong a tsoetsoeng ke Down syndrome a hlaha ho basali ba ka tlaase ho 35 'me ka karolelano lilemo tsa' mè oa ngoana ea nang le Down syndrome ke lilemo tse 28. Ka kakaretso, monyetla oa hore mosali ea ka tlaase ho lilemo tse 30 a be le ngoana ea nang le Down syndrome o tlase ho 1: 1000. Kotsi e eketseha ha mosali a ntse a hōla, 'me a ka ba le 1: 112 a le lilemo li 40. Leha ho le joalo, sena se ntse se le tlaase ho karolo ea 1 lekholong ea basali ba nang le moimana ha ba le lilemo li 40.
Tšoantšiso ea lilemo tsa boimana le kotsi ea Down syndrome e fumaneha, empa ke habohlokoa ho lemosa basali pele ba sheba chate ena. Etsa bonnete ba hore u hopola hore basali ba bangata ba nang le bokhachane ba fetang lilemo tse 35 ba na le masea a se na Down syndrome.
Basali ba bang ba fetang lilemo tse 35 (kapa ba na le mabaka a mang a kotsi) ba ka khetha ho ba le amniocentesis ho hlahloba Down syndrome kapa liteko tse ling tsa bokhachane. Qeto ea hore na liteko tsena li ka etsoa kapa che, ke tsa botho, 'me li lokela ho etsoa ka thuso ea tlhahiso ea liphatsa tsa lefutso. American College of Obstetrics le Gynecology e khothalletsa hore basali bohle ba fanoe ka tlhahlobo ea bokhachane bakeng sa Down syndrome. Basali ba bang ba khetha ho etsa tlhahlobo ena ka bobeli bakeng sa ho khothatsoa le ho ba le matla a ho rera pele, ha ho na le mabaka a hlakileng a etsang hore basali ba khethe ho se be le liteko tsa bakhachane.
Kotsi ea Paternal le Down Syndrome
Ho hakanngoa hore chromosome e eketsehileng ea Down syndrome e tsoa ho 'mè boholo ba nako le ho ntate (sperm) karolo ea 4 lekholong feela ea nako. Ha tsoelo-pele ea botsofali e ntse e lekana le kotsi ea Down syndrome, ha ho joalo le ka ho hōla ka lilemo tsa bo-ntate feela ka lebaka la hore mahe a tsofala, empa peō e ntse e etsoa ka nako e telele e le hore e be libeke tse 'maloa feela. Leha ho le joalo, ho na le maemo a liphatsa tsa lefutso tse ling ntle le Down syndrome tse amanang le lilemo tse tsoetseng pele tsa bo-ntate, tse kang achondroplasia (dwarfism) le Marfan syndrome.
Lipatlisiso le Bokamoso
Ka puo e buang ka Human Genome Project le gene therapy batsoali ba 'nile ba botsa potso e ntle haholo: "Ke hobane'ng ha phekolo ea liphatsa tsa lefutso e ke ke ea sebelisoa ho lokisa ho se tloaelehe ha liphatsa tsa lefutso ho Down syndrome?" Ka bomalimabe, kutloisiso ea rona ea liphatsa tsa lefutso ha e sa le teng. Seo phekolo ea liphatsa tsa lefutso e ka thusang bonyane haufinyane, e sebetsana le mefuta e sa tloaelehang ea liphatsa tsa lefutso. Boemo bo bakoang ke liphatsa tse fetang tse le 'ngoe, ho se ke ha e-ba le kromosome eohle e tla ba thata ho e phekola ka phekolo ea liphatsa tsa lefutso. Ka hona bafuputsi ba shebile se ka etsahalang ka epigenetic engineering-epigenetics ke tšimo e shebileng polelo (litlhaloso tsa meriana ea liphatsa tsa lefutso ho e-na le liphatsa tsa lefutso ka bobona).
Seo se boletse, tsamaiso ea bana ba tsoetsoeng ke Down syndrome e ntlafalitsoe haholo lilemong tse mashome a seng makae tse fetileng.
Ntho e ka tlaase
Ntlha ea bohlokoa ke hore re tseba hore ho na le kamano kapa botsoalle pakeng tsa lilemo tsa 'mè le kotsi ea ho ba le ngoana ea nang le trisomy e kang Down's syndrome, empa ha ho na motho ea tsebang mohloli o itseng oa lintho tse bohloko.
Lisebelisoa:
Dekker, A., De Deyn, P., le M. Rots. Epigenetics: Senotlolo se sa hlokomoloheng sa ho fokotsa litšenyehelo tsa ho ithuta le ho hopola ho Down Syndrome. Litsebi tsa thuto ea kelello le Litlhahlobo tsa Boits'oaro . 2914. 45: 72-84.
Mentis, A., Engineering ea Epigenomic bakeng sa Down Synrome. Litsebi tsa thuto ea kelello le Litlhahlobo tsa Boits'oaro . 2016. 71: 323-327.