science
THE STRAITS TIMES MONDAY, FEBRUARY 20 2012 PAGE D22
WHEN TWO BECOME ONE
Twins are a rare occurrence in birth and only the fortunate ones are able to escape the occasional outcome of birth complications. In the darkness of a woman’s womb, no one knows how her eggs would be fertilised or how it would develop. Not even the best doctors can predict what would happen. The Straits Times takes a look at the facts, figures, and the difficulties faced by one such rare occurrence of Siamese Twins.
IN THE PAST
Throughout the years, there has been many documentations of conjoined twins, here is a list of those who have made it famous with their strength and willpower to survive.
300 CE: Moche culture of Ancient Peru depicted their conjoined twins on their ceramics.
One of the most common type of conjoined twins Craniopagus. This pair of twins, Rital and Ritag Gaboura, have survived the odds, staying alive through birth. Craniopagus affects one in 10 million births, approximately 40% percent are stillborn or die during labour, a third die within 24-hours, while just 25% survive.
Year 942: Earliest known documented case of conjoined twins (joined at abdomen) brothers who were brought to Constantinople for evaluation.
Year 1100-1134: Mary and Eliza Chulkhurst, conjoined at the back, were the best-known early historical example of conjoined twins also known as “the Biddenden Maids”.
They further defied the odds and pulled through multiple operations in Great Ormond Street Hospital, London, and finally one that separated them both on 15 August 2011.
Millie and Christine McCoy (July 11, 1851 - October 8, 1912) are conjoined twins well-known as stage names "Two-Headed Nightingale" or "Two-Headed Lady”. 19th Century: Chang and Eng Bunker (1811–1874), from Thailand, joined by the areas around their xiphoid cartilages; the expression Siamese twins is derived from their case. They gained fame and fortune by working as circus performers.
20th Century: Ladan and Laleh Bijani of Shiraz, Iran (Persia) (1974–2003); died during separation surgery in Singapore. They were the first pair of adult conjoined twins to be operated upon.
Abigail and Brittany Hensel, born March 7, 1990 in Carver County, Minnesota, United States of America, dicephalic conjoined twins, two heads, two arms, two legs, cannot be separated.
Rose and Grace Attard ("Mary and Jodie"), Maltese twins joined at spine, born October 2000. Separated in Great Britain by court order against the wishes of their parents, because Mary could not survive independently. Mary died upon separation (Photo on the right depicts surviving twin).
The most recent pair of Craniopagus conjoined twins named Rital and Ritag undergoing a successful operation.
HOW IT HAPPENS The beginning development of the cells are the same for all twins. However, for conjoined twins, the egg cells are unable to split completely. There are two instances of how monozygotic twins are developed. One is when the embryonic cells locate and fuse together again, the other is when the cells are unable to fully split itself into two.
Egg cell is being fertilised
º Egg cell continue to split and develop independently. Healthy enzygotic twins develop from here.
Egg cell splits into two
TYPES OF CONJOINED TWINS 34% are Omphalopagus
Two bodies are merged at the lower chest, the heart is never involved; however, twins
often share a liver, digestive system, diaphragm and/or other organs.
STATISTICS 1 in 200,000
LESS COMMON TYPES
6% are Ischiopagus
Merged lower half of the two bodies, spines joined end-to-end at a 180° angle, one set of genitalia and anus; have varying (2-4) number of limbs.
Cephalopagus: Two faces on opposite sides of a single head; the upper portion of the body is merged while the bottom portions are separate. Twins generally cannot survive due to severe malformations of the brain.
live births are conjoined twins
1.9% 25% 3:1
Xiphopagus: Two bodies merged in the xiphoid cartilage, which is approximately from the navel to the lower breastbone. Twins almost never share any vital organs, with the exception of the liver. 40% are Thoracopagus
Two bodies are merged from the upper thorax to lower belly. The heart is usually involved in these cases.
18% are Pygopagus (Iliopagus)
Two bodies joined at the pelvis.
2% are Craniopagus Merged skulls with separate bodies.
Nigeria
Parapagus: Fused side-by-side with a shared pelvis.
LIVES OF CONJOINED TWINS IN SNIPPETS
Yoruba
Despite the fact that conjoined twins can live a life as how humans do, many people still treat them differently. An example would be the Chang and Eng brothers who were simultaneously arrested for debt and recruited into the armed services. Another example would be Millie and Christine McCoy who were conjoined twins born into slavery in North Carolina. The two are separated from their family and sold several times. Their last owner reunites them with their family. Advertised as the "Two-Headed Nightingale" or "Two-Headed Lady," the twins are said to be fluent in five languages and
of the world’s population is made up of twins - the overall Survival rate for conjoined twins ratio of female to male conjoined twins
The highest birthrate for twins is in Yoruba where the live birth rate is 45 per every 1000 births. Scientists believe that this is related to the consumption of phytoestrogenscontaining (female sex hormone that can cause two eggs to be released) yam.
perform all over the world as pianists, singers and dancers. Lori and George Schappell, world’s longest living conjoined twins have experienced the joy of loving. Lori has been in a relationship. They lead very normal lives just as how Abigail and Brittany Hansel, as well as many other conjoined twins have lived their lives. Sometimes all we need is someone to give us a smile and some encouragement. Next time when you see a conjoined twin, give them your blessings, for they are the unique one in 200,000 live births.
Written & Designed By: SIM XIN FENG | Sources: WIKIPEDIA, BBC NEWS, TWINSTUFF.COM, TWINSY.WORDPRESS, CAMBRIDGE UNIVERSITY LIBRARY, THE SUN NEWS