What You Need to Know About Cholesterol: MedlinePlus Health News

What You Need to Know About Cholesterol: MedlinePlus Health News

Cholesterol plays a vital role in your health, so it's important to understand the different types of cholesterol and how to influence their levels, a heart specialist says.

New Algorithms in Prenatal Diagnosis

New Algorithms in Prenatal Diagnosis

INTRODUCTION

The approach in prenatal diagnosis has been revolutionized by advances in prenatal molecular diagnostics. New algorithms in prenatal diagnosis are evolving and becoming increasingly complicated (Figure 1). The goal is to maximize the prenatal information for pregnant women and the families to make choices for the next generations.

Down syndrome screening has been the focus in prenatal diagnosis for a long time. However, many other chromosomal and structural foetal abnormalities were diagnosed incidentally during the  screening programme for Down syndrome, coupled with the 18–22 weeks foetal anomaly ultrasound. Combined screening at 11–13 weeks by maternal age, foetal nuchal translucency (NT) thickness by ultrasound, maternal serum pregnancy-associated plasma protein A (PAPP-A) and free beta-human chorionic gonadotropin (β-hCG) can identify 90% of foetuses with trisomy 21 (Down syndrome) and other common aneuploidies (trisomies 18 and 13) at a false-positive rate (FPR) of 5%.1

The performance is highly reproducible worldwide and has also been demonstrated in the Hospital Authority universal Down syndrome screening programme in Hong Kong from 2010.2 Additional ultrasound and maternal serum markers with different contingent screening tests have been studied to further improve the detection rates and to reduce the FPR.

An important breakthrough in prenatal screening using maternal plasma cell-free foetal DNA as a noninvasive prenatal testing (NIPT) for foetal chromosomal abnormalities was discovered by Professor Dennis Lo from Hong Kong.3 The detection rate for Down syndrome using NIPT is >99% with an FPR of as low as 0.1%. NIPT can be performed using maternal blood sample from 10 weeks’ gestation onwards. NIPT is currently available as a secondary screening tool for pregnancies with positive conventional Down screening as well as for primary screening for Down syndrome.4-6

For prenatal diagnosis in the 21st century, traditional karyotyping is no longer adequate. Advances in prenatal molecular diagnostics including polymerase chain reaction (PCR) as rapid aneuploidy test, and chromosomal microarray (CMA) as molecular karyotyping including the detection of microdeletions and microduplications, are going to replace traditional karyotyping sooner or later.7 There are also new modalities being developed such as whole exome sequencing, WES (sequencing all the protein-coding genes in the genome) or whole genome sequencing, WGS (sequencing the entire genome). WES or WGS will not be discussed in this review article.

Despite the rapid ongoing development in prenatal molecular diagnostics, ultrasound maintains a pivotal role in the new algorithms (Figure 1), being the link between the various tests inside the algorithms. In modern prenatal diagnosis, continued utility of ultrasound (with corresponding counselling) could offer career sustainability for foetal medicine specialists.

This review article is focused on the new algorithms in prenatal diagnosis (Figure 1) from a clinical service/clinical pathway point of view. The current situation in Hong Kong will be referred to from time to time for illustration. It is beyond the author’s capacity to go in-depth into the laboratory aspects.

S¸u nguyªn t¾c c¬ b¶n

®Ó cã cuéc sèng kháe m¹nh 

1.  NÕu b¹n hót thuèc, h·y bá thuèc ngay b©y giê. Hót thuèc lµ nguyªn nh©n tö vong hµng ®Çu ë Mü; nã lµ yÕu tè chÝnh trong bÖnh tim m¹ch vµnh vµ ung thư­ phæi, miÖng, thùc qu¶n, häng, bµng quang vµ cæ tö cung. Hót thuèc lµm cho da, x­¬ng vµ phæi nhanh bÞ "giµ" ®i.

2.  NÕu b¹n uèng r­îu th× h·y uèng ®iÒu ®é l¹i. Kh«ng ®­îc uèng bÊt kú lo¹i r­îu nµo nÕu b¹n cã thai hoÆc ®ang l¸i xe hay vËn hµnh m¸y mãc. NÕu b¹n nghiÖn r­îu h·y gäi  thÇy thuèc hoÆc bÖnh viÖn ®Þa ph­¬ng cña b¹n ®Ó ®­îc gióp ®ì.

3.  Chän mét vµi bµi tËp thÓ dôc mµ b¹n thÝch thó, nh­ ®i bé hoÆc b¬i léi vµ thùc hiÖn nã Ýt nhÊt 5 lÇn mét tuÇn víi mçi ngµy Ýt nhÊt 30 phót. Cã thÓ chia thµnh nhiÒu giai ®o¹n mçi 10 hoÆc 15 phót ®Ó dÔ dµng h¬n cho viÖc thÝch nghi.

4.  ¡n nhiÒu thùc phÈm tù nhiªn nh­ ngò cèc, tr¸i c©y vµ rau t­¬i. Sö dông tiÕt chÕ nh÷ng thùc phÈm cã chøa mì. H·y tham kh¶o c¸c biÓu ®å vµ nh÷ng h­íng dÉn c¸c thµnh phÇn cña chÕ ®é ¨n cã lîi cho søc kháe vµ c¸ch thøc ¨n uèng ®¶m b¶o søc kháe.

5.  H·y gi÷ cho c¬ thÓ cña b¹n ®­îc thon th¶. Kh«ng ®Ó cho b¹n hoÆc nh÷ng ®øa trÎ cña b¹n qu¸ bÐo. Sù bÐo ph× liªn quan ®Õn nhiÒu rèi lo¹n nghiªm träng nh­ lµ bÖnh tim vµ bÖnh ®¸i th¸o ®­êng. NÕu b¹n bÞ t¨ng träng th× h·y cè g¾ng ®Ó thùc hiÖn l©u dµi sù thay ®æi trong c¸ch thøc ¨n uèng vµ thãi quen tËp thÓ dôc cña b¹n.

6.  H·y kiÓm tra søc kháe th­êng xuyªn. Nh÷ng xÐt nghiÖm sµng läc cã thÓ ph¸t hiÖn nhiÒu bÖnh tËt ë giai ®o¹n sím khi mµ chóng cã thÓ ®­îc ®iÒu trÞ thµnh c«ng. ThÇy thuèc cña b¹n cã thÓ nãi cho b¹n biÕt nh÷ng xÐt nghiÖm nµo nªn lµm.

                                                  BS. Ngô Đức Huy