Ukungabekezelelani kwe-lactose

Ukungabekezelelani kwe-Lactose yisimo esivamile esidalwa ukwehla kwekhono lokugaya i-lactose, ushukela otholakala emikhiqizweni yobisi. Labo abathintekile bayehluka ebuningini be-lactose abangabubekezelela ngaphambi kokuba izimpawu ziqhamuke Izimpawu zingabandakanya ubuhlungu besisu, ukuqunjelwa, isifo sohudo, igesi kanye nesicanucanu. kuncike enanini umuntu alidlayo noma aliphuzayo.Ukungabekezelelani kwe-lactose akubangeli ukulimala emgodini wamathumbu.


Ukungabekezelelani kwe-Lactose kungumphumela wokushoda kwe-lactase, okungaba yizakhi zofuzo (i-hypolactasia eyinhloko kanye ne-alactasia eyinhloko yokuzalwa) noma okubangelwa imvelo (i-hypoalactasia yesibili noma etholakele). Kunoma ikuphi, izimpawu zibangelwa amazinga anganele e-lactase kulwelwesi lwe-duodenum. I-Lactose, i-molecule ye-disaccharide etholakala obisini nasemikhiqizweni yobisi, ayikwazi ukufakwa ngqo odongeni lwamathumbu amancane iye egazini, ngakho-ke, lapho i-lactase ingekho, idlula ihambisane nekholoni [ukucaphuna kuyadingeka]. Amagciwane kukholoni angakwazi ukugaya i-lactose, futhi ukuvutshelwa okuvelayo kuveza inani eliningi legesi (ingxube ye-hydrogen, i-carbon dioxide, ne-methane) edala izimpawu ezahlukahlukene zesisu. Ushukela ongagunyaziwe nemikhiqizo yokuvutshelwa nayo iphakamisa ingcindezi ye-osmotic yekoloni, idala ukugeleza kwamanzi okwenyuka kuya emathunjini (isifo sohudo).


Uhlobo lwe-LCT luhlinzeka ngemiyalo yokwenza i-lactase. Ukulandelana okuthile kwe-DNA kuhlobo lwe-MCM6 kusiza ukulawula ukuthi ngabe uhlobo lwe-LCT luvuliwe noma luvaliwe. Okungenani eminyakeni eyizinkulungwane ezimbalwa ezedlule, abanye abantu baqala ukuguquka kwesakhi sofuzo se-MCM6 esigcina isakhi sofuzo se-LCT sivuliwe noma ngabe ukumiswa kokuncelisa ibele. Izakhi zofuzo ze-LCT ne-MCM6 zombili zitholakala engalweni ende (q) ye-chromosome 2 esifundeni 21. I-locus ingachazwa njenge-2q21. Ucwaningo lwango-2016 lwabahlanganyeli abangaphezu kuka-60,000 abavela emazweni angama-89 bathola ukwanda kwesifunda kwe-lactose malabsorption kwakungu- "64% (54-74) e-Asia (ngaphandle kwaseMpumalanga Ephakathi), 47% (33-61) empumalanga yeYurophu, eRussia, nasezweni elaliyiSoviet Republic , 38% (CI 18-57) eLatin America, 70% (57-83) eMiddle East, 66% (45-88) enyakatho ye-Afrika, 42% (13-71) enyakatho neMelika, 45% ( 19-71) e-Oceania, 63% (54-72) e-Afrika eseningizimu yeSahara, kanye no-28% (19-37) enyakatho, eningizimu nasentshonalanga yeYurophu. " NgokukaJohn Hopkins Medicine, ukungabekezelelani kwe-lactose kungaphezulu ezivamile kubantu base-Asia baseMelika, baseMelika baseMelika, baseMelika baseMexico nabaseMelika baseMelika. Ukuhlaziywa kwe-DNA yamathambo asendulo angama-94 eYurophu naseRussia kwaphetha ngokuthi ukuguquka kokubekezelelana kwe-lactose kwavela eminyakeni engaba ngu-4 300 edlule futhi kwasakazeka kulo lonke elaseYurophu.


Abanye abantu bakhulise ukuphikelela kwe-lactase, lapho ukukhiqizwa kwe-lactase kuyaqhubeka nokuba mdala mhlawumbe njengempendulo ezinzuzweni zokugaya ubisi ezilwaneni zasemapulazini. Abanye bathi lokhu kuxhumanisa ukungabekezelelani nokukhethwa kwemvelo okuthanda abantu abaphikelela nge-lactase, kepha futhi kuyahambisana nempendulo yomzimba yokwehlisa ukukhiqizwa kwe-lactase lapho kungadingeki kumasiko lapho imikhiqizo yobisi ingewona umthombo wokudla otholakalayo. IYurophu, i-India, i-Arabia ne-Afrika kucatshangwa ukuthi kuqala ukuphikelela kwe-lactase ngenxa yokuguquka okukodwa, ukuphikelela kwe-lactase kulandelwe ekuguqulweni okuningana okwenzeke ngokuzimela. Abantu baseMpumalanga Afrika, ngokuphikelela kusuka ku-26% eTanzania kuya kuma-88% kubantu baseBeja abelusi eSudan.


Ukuqoqwa kwezici ze-epigenetic, ngokuyinhloko i-DNA methylation, esifundeni se-LCT esandisiwe, kufaka phakathi isithuthukisi sezakhi zofuzo esisejini ye-MCM6 eduze ne-C / T-13910 SNP, nakho kungaba nomthelela ekuqaleni kokungabekezelelani kwe-lactose kubantu abadala. I-LCT kumagundane i-epithelium yamathumbu ibe yi-DNA methylation ku-enhancer gene.


Ukungabekezelelani kwe-Lactose kuhlukaniswa ngokwezimbangela zayo njenge:


I-hypolactasia eyinhloko

I-hypolactasia eyinhloko, noma ukushoda kwe-lactase okuyisisekelo, kuyizakhi zofuzo, kuthinta kuphela abantu abadala, futhi kubangelwa ukungabikho kokuphikelela kwe-lactase. Kubantu ngaphandle kokuphikelela kwe-lactase, i-lactase encane ikhiqizwa ngumzimba ngokuhamba kwesikhathi, okuholela ku-hypolactasia lapho usumdala. Imvamisa yokuphikelela kwe-lactase, evumela ukubekezelelana kwe-lactose, yehluka kakhulu emhlabeni wonke, nokutholakala okuphezulu kakhulu eNyakatho-ntshonalanga Yurophu, kwehla ngaseningizimu yeYurophu naseMpumalanga Ephakathi futhi kuphansi e-Asia nakwiningi le-Afrika, yize kuvamile kubantu abelusayo abavela e-Afrika .


Ukuhlelwa kwe-hypolactasia kwesibili

I-hypolactasia yesibili noma ukushoda kwe-lactase yesibili, okubizwa nangokuthi ukutholwa kwe-hypolactasia noma ukutholakala kwe-lactase, kubangelwa ukulimala emathunjini amancane. Lolu hlobo lokungabekezelelani kwe-lactose lungenzeka kuzo zombili izinsana nakubantu abadala be-lactase futhi luyaguquguquka.Lungabangelwa i-gastroenteritis, isifo se-celiac, isifo sikaCrohn, i-ulcerative colitis, i-chemotherapy, izimuncagazi emathunjini (njenge-giardia), noma ezinye izimbangela zemvelo. .


I-alactasia yokuzalwa eyinhloko

I-alactasia eyisiqalo yokuzalwa, ebizwa nangokuthi ukushoda kwe-congenital lactase, yinto engavamile ngokweqile, i-autosomal recessi.