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JULY , 2018 | The HEALTH
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OB-GYN
Prenatal testing to detect chromosomal abnormalities
Prenatal testing is gaining prominence among couples these days to detect and reduce risk and miscarriages . Columbia Asia Hospital Klang Consultant Obstetrician & Gynaecologist Dr Yip Khar Weng explained that the procedure involves maternal blood taken from the mother to detect the fetus DNA .
“ By analysing the DNA , we would be able to identify if the fetus is at risk of having certain types of chromosomal disorders . Off course , in all those test , the most important chromosomal disorders that we would try to detect is Down syndrome .”
“ Another thing about this test is that it is able to detect if the baby is normal or abnormal . This test gives a fairly accurate detection of 99.9 per cent .”
PATAU syndrome is caused by chromosomal abnormalities in which some of the cells contain extra genetic material from chromosome 13 . The extra genetic material disrupts normal development , causing multiple and complex organ defects which is lethal to the developing embryo .
Columbia Asia Hospital Klang Consultant Obstetrician & Gynaecologist Dr Yip Khar Weng explained that infants with Patau syndrome usually have facial abnormalities such as cleft lips and cleft palate .
“ Eyes may be very close together and in an extreme condition – the baby may have only one eye which is called the cyclops eyes .”
However , this isn ’ t as common as Down syndrome , as Yip pointed out that it depends on the age of the mother which increases after the age of 35 .
Other symptoms include abnormality of the brain , where there might not be a partition in the left brain and the right brain . The child may not have two nostrils but only one nostril , or the nose may be elongated .
“ If the test returns and tells you that it ’ s at high risk of Down syndrome or certain syndromic risk , you still need to do a confirmatory test where the actual DNA of the baby is screened by extracting the amniotic fluid to test the karyotyping of the baby ,” he said .
The test is also run to detect two other syndromes ; one that involves Trisomy 13 which is the Patau syndrome and the other that involves Trisomy 18 - the Edwards syndrome .
BY DR YIP KHAR WENG
Understanding Patau syndrome
A new born baby with Patau syndrome .
With the advancement of technology , this test is able to detect any abnormal chromosomal disorders . However , although these test can detect all disorders , the accuracy is not the same . Meaning that the accuracy for Down syndrome may be 99 per cent compared to Patau syndrome or Edwards syndrome where the accuracy may be at 91 per cent .
TOGETHER WE LEARN IN MEDICINE
Can a baby survive Edwards syndrome ?
EDWARDS syndrome is associated with multiple neuromuscular abnormality and would usually face death either immediately after delivery or they would survive a few hours to a few days .
Columbia Asia Hospital Klang Consultant Obstetrician & Gynaecologist Dr Yip Khar Weng explained that it ’ s hard for babies with Edwards syndrome to adapt to living environment .
“ Edwards syndrome causes the baby to be small during pregnancy , have abnormal features such as overlapping fingers and weighing a meagre 1.6kilogrammes below the normal weight of 2.5 kilogrammes .”
“ The legs may also have some form of deformity which is known as rocker bottom foot where the heel part would be very rounded .”
These are largely caused by the mother ’ s age and not inherited unless the mother or father has an abnormal arrangement of genetics .
Most of the time , mothers will not have any symptoms . Hence a prenatal testing need to be done early from 10 weeks of pregnancy to detect such chromosomal abnormalities .