Lokacin da muke tunanin ciwon Down, yanayin farko da muke tunani shine trisomy 21, ko Down syndrome. Ta yadda idan muka yi magana game da mutumin da ke da Down syndrome, muna la'akari da cewa suna da Down's syndrome.
Duk da haka, trisomy yana bayyana sama da duk wani anomaly na kwayoyin halitta, don haka yana iya ɗaukar nau'i daban-daban. Don haka a zahiri akwai nau'ikan Ciwon Down's da yawa.
Menene Ciwon Down?
Ciwon Down yana sama da duk labarin Kwayoyin kwayoyi. Muna magana game da aneuploidy, ko fiye da sauƙi na chromosomal anomaly. A cikin mutum na yau da kullun, wanda baya fama da ciwon Down, chromosomes suna tafiya bibiyu. Akwai nau'i-nau'i 23 na chromosomes a cikin mutane, ko kuma 46 chromosomes a duk. Muna magana akan trisomy lokacin da aƙalla ɗaya daga cikin nau'ikan ba shi da biyu, amma uku chromosomes.
Wannan chromosomal anomaly zai iya faruwa a lokacin rarraba gadon gado na abokan biyu a lokacin ƙirƙirar gametes (oocyte da spermatozoon), sannan a lokacin hadi.
Ciwon Down na iya yin tasiri kowane nau'i na chromosomes, wanda aka fi sani da shi shine abin da ya shafi chromosomes biyu na 21. A zahiri, ana iya samun trisomies da yawa kamar yadda ake samun nau'ikan chromosomes. A cikin mutane kawai, yawancin trisomies suna ƙarewa a cikin zubar da ciki, saboda tayin ba zai iya yiwuwa ba. Wannan shine lamarin musamman ga trisomy 16 da trisomy 8.
Wadanne nau'ikan cutar Down's syndrome ne suka fi yawa?
- Trisomy 21, ko Down syndrome
Trisomy 21 shine halin yanzu farkon gano dalilin da ya haifar da raunin kwakwalwar kwayoyin halitta. Hakanan shine trisomy mafi kowa kuma mai yiwuwa. Ana lura da shi a matsakaita yayin masu juna biyu 27 a cikin 10 kuma yawan sa yana ƙaruwa da shekarun haihuwa. Akwai kusan haihuwar yara 000 masu fama da cutar Down a kowace shekara a Faransa, a cewar Cibiyar Lejeune, wacce ke ba da. taimakon likita da tunani ga wadanda abin ya shafa.
A cikin trisomy 21, chromosome 21 yana cikin ninki uku maimakon biyu. Amma akwai “ƙasassun rukuni” don tantance trisomy 21:
- kyauta, cikakke kuma mai kama da trisomy 21, wanda ke wakiltar kusan 95% na lokuta na trisomy 21: chromosomes guda uku 21 sun rabu da juna, kuma an lura da anomaly a cikin dukkanin kwayoyin da aka bincika (akalla waɗanda aka bincika a cikin dakin gwaje-gwaje);
- mosaic trisomy 21 : Kwayoyin da ke da chromosomes 47 (ciki har da 3 chromosomes 21) suna rayuwa tare da kwayoyin halitta tare da chromosomes 46 ciki har da 2 chromosomes 21. Matsakaicin nau'i na nau'i biyu na sel ya bambanta daga wannan batu zuwa wani kuma, a cikin mutum ɗaya, daga mutum zuwa wani. gabobi ko nama zuwa nama;
- trisomy 21 ta hanyar fassara Karyotype na genome yana nuna chromosomes guda uku 21, amma ba duka aka haɗa su ba. Daya daga cikin ukun chromosomes 21 na iya zama misali tare da chromosomes guda biyu 14, ko 12…
Babban alamun cutar Down's syndrome
« Kowane mai ciwon Down na farko da kansa, na musamman ne, yana da cikakkiyar gadon gado da kuma hanyarsa ta asali na tallafawa wannan wuce gona da iri. », Cikakkun bayanai na Cibiyar Lejeune. Yayin da akwai babban bambanci a cikin alamun bayyanar cututtuka daga mutum ɗaya mai ciwon Down zuwa wani, akwai wasu halaye na zahiri da na hankali na gama gari.
Nakasuwar hankali koyaushe ne, ko da an yi alama fiye ko žasa daga mutum ɗaya zuwa wani. Hakanan akwai alamun bayyanar cututtuka na zahiri: kanana da zagaye kai, kanana da faffadan wuya, bude idanu masu fadi, strabismus, tushen hanci mara sani, hannaye da gajerun yatsu… nahaihu rikitarwa wani lokaci ana iya ƙarawa zuwa waɗannan alamun, kuma suna buƙatar kulawa mai zurfi na likita: zuciya, ido, narkewar abinci, rashin lafiyar kasusuwa…
Don ƙarin jure wa waɗannan rikice-rikice da iyakance nakasa ta jiki da ta hankali, Kulawa da yawa ga mutanen da ke fama da ciwon Down : masana kimiyyar halitta, masu kwantar da hankali na psychomotor, likitocin motsa jiki, masu ilimin magana…
- Trisomy 13, ko kuma ciwon Patau
Trisomy 13 yana faruwa ne saboda kasancewar na uku chromosomes 13. Masanin ilimin halittar dan adam Klaus Patau dan kasar Amurka ne ya fara siffanta shi, a shekarar 1960. An kiyasta faruwar lamarin a tsakanin 1/8 zuwa 000/1 haihuwa. Abin baƙin cikin shine wannan ƙwayar ƙwayar cuta tana da mummunan sakamako ga ɗan tayin da abin ya shafa: mummunan yanayin kwakwalwa da na zuciya, rashin lafiyar ido, lalacewar kwarangwal da tsarin narkewar abinci…. Mafi rinjaye (kimanin 15-000%) na 'yan tayin da abin ya shafa suna mutuwa in utero. Kuma ko da ya rayu, jariri mai ciwon Down yana da mai ƙarancin rai rai, 'yan watanni zuwa 'yan shekaru dangane da rashin daidaituwa, kuma musamman a cikin yanayin mosaicism (daban-daban genotypes yanzu).
- Trisomy 18, ko Edwards ciwo
Trisomy 18 yana nuna, kamar yadda sunansa ya nuna, kasancewar ƙarin chromosome 18. An fara bayyana wannan cutar ta dabi'a a cikin 1960 ta masanin ilimin halittar dan kasar Ingila John H. Edwards. Anyi kiyasin faruwar wannan trisomy a 1/6 zuwa 000/1 haihuwa. A cikin 18% na lokuta, trisomy 95 yana haifar da sakamako mutuwa in utero, ya tabbatar da shafin Marayu, tashar yanar gizo don cututtukan da ba kasafai ba. Saboda tsananin ciwon zuciya, jijiya, narkewar abinci ko ma nakasa na koda, jariran da ke da trisomy 18 gabaɗaya suna mutuwa a cikin shekarar farko ta rayuwa. Tare da mosaic ko translocation trisomy 18, tsammanin rayuwa ya fi girma, amma baya wuce balaga.
- Down's syndrome yana shafar chromosomes na jima'i
Tunda an ayyana trisomy ta kasancewar ƙarin chromosome a cikin karyotype, ana iya haɗa dukkan chromosomes, gami da chromosomes na jima'i. Hakanan akwai trisomies da ke shafar nau'in chromosomes X ko XY. Babban sakamakon waɗannan trisomies shine rinjayar ayyukan da ke da alaƙa da chromosomes na jima'i, musamman matakan hormones na jima'i da gabobin haihuwa.
Akwai nau'ikan chromosome na jima'i guda uku:
- trisomy X, ko sau uku X ciwo, lokacin da mutum yana da chromosomes X guda uku. Yaron da ke da wannan trisomy mace ce, kuma baya gabatar da wasu manyan matsalolin lafiya. Wannan anomaly na kwayoyin halitta sau da yawa gano a lokacin balagagge, a lokacin zurfafa bincike.
- Klinefelter ciwo, ko XXY trisomy : mutum yana da X chromosomes guda biyu da Y chromosome guda daya. Mutum gabaɗaya namiji ne, kuma rashin haihuwa. Wannan trisomy yana haifar da matsalolin lafiya, amma ba wani babban nakasa ba.
- Cutar ciwon Yakubu, ko trisomy 47-XYY : kasancewar Y chromosomes biyu da X chromosomes. Mutum namiji ne. Wannan anomaly na kwayoyin halitta ba ya haifar da babu alamun bayyanar cututtuka babba, ana lura da shi sau da yawa a lokacin girma, yayin karyotype da aka yi don wata manufa.
Ƙananan alamomi, waɗannan rashin daidaituwa na kwayoyin halitta game da chromosomes X da Y ba a cika gano su ba. cikin mahaifa.
A daya bangaren, duk sauran trisomies (trisomy 8, 13, 16, 18, 21, 22…), idan ba a dabi'a ba su haifar da zubar da ciki ba tare da bata lokaci ba, yawanci ana zargin su akan duban dan tayi, idan aka ba da jinkirin girma, ta amfani da ma'aunin translucency, trophoblast biopsy, ko ' amniocentesis, don yin karyotype idan akwai yiwuwar trisomy. Idan an tabbatar da nakasar trisomy, ƙungiyar likitoci ta ba da shawarar dakatar da ciki na likita.