Læknablaðið - 15.03.1993, Blaðsíða 31

LÆKNABLADID
119
Helstu vandamál vid skimun med mælingum
á AFP hjá pungudum konum er skortur á
sértæki og nænti. Hjá adeins 1,3% peirra
kvenna sem höfdu s-AFP gildi undir
vidmidunarmörkum, var prístæda 21 til
stadar hjá fóstri og eitt tilfelli af prístædu 21
hjá rannsóknarhópnum hefdi ekki fundist.
Framskyggnar athuganir benda til pess ad
næmi sé jafnvel minna fyrir yngri aldurshópa
eda adeins um 20% (18). Vegna pessa hefur
verid leitad annarra leida til ad auka næmi og
sértæki skimunarinnar. Erlendar rannsóknir
hafa sýnt, ad med pví ad rnæla ótengt estríól
og human chorionic gonadotropin (hCG) í
sermi pungadra kvenna til vidbótar vid s-
AFP má ná betri árangri í fósturgreiningu
á litningagöllum, en s-hCG er hækkad í
medgöngu med prístædu 21, en estríól lækkad
(18,19). Med pví ad meta pessa áhættupætti
til vidbótar vid aldursáhættu konunnar er talid
ad finna megi um 60 af hundradi tilfella af
prístædu 21 hjá fóstrum (18). Ef ákvördun
verdur tekin unt ad hefja almenna skimun
fyrir pnstædu 21 hjá öllum pungudum konum
á Islandi, sem pess æskja, væri æskilegt
ad pessar prjár mælingar verdi notadar til
vidbótar vid aldur konunnar.
LOKAORD
Mælingar á AFP í sermi módur geta pannig
gefid mikilvægar upplýsingar um ástand
fósturs. Gildi hærri en 2,5 MAM benda
til klofins hryggjar eda heilaleysis, en hátt
hlutfall falskt jákvædra svara rýrir gildi
mælinganna til skimunar, auk pess sem
nákvæm ómskodun er nú talin fullnægjandi
í pessum tilgangi. Lág s-AFP gildi eru hins
vegar vísbending um litningagalla, fyrst og
fremst prístædu 21, og má pví nota slíkar
mælingar vid skimun annarra aldurshópa en
peirra, sem falla undir núverandi ábendingar
um legástungur. Med pví ad mæla einnig
estríól og hCG má auka bædi næmi og sértæki
rannsóknarinnar. Adur en tekin er ákvördun
uin slíka skimun, er hins vegar naudsynlegt
ad tryggja, ad adstada til erfdarádgjafar,
legástungna og litningarannsókna sé fyrir
hendi fyrir pann hóp, sem pannig myndi
bætast vid.
SUMMARY
To explore the relationship between maternal s-
AFP and fetal trisomy 21 in the second trimester
in Iceland and to establish normal values for
s-AFP for the National Hospital Biochemical
Laboratory, s-AFP values for 1309 women that
had undergone second trimester amniocentesis were
examined retrospectively and the results presented
as »multiples of medians« for different weeks of
gestation. These values and the outcomes of the
amniocentesis with regard to trisomy 21 were
compared to risk tables presented by Cuckles et
al, combining age and s-AFP risk. Down syndrome
was found in ten out of 763 pregnancies (1.3%)
with increased combined risk, compared with
one Down syndrome in 546 pregnancies (0.2%)
with decreased combined risk. lt is suggested that
screening for fetal chromosomal anomalies in all
age groups should be considered in lceland, either
by s-AFP alone or in combination with hCG and
estriol, as this has been shown in other studies to
increase the sensitivity and the specificity of such
screening.
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