Twin studies have been used to distinguish between genetic and environmental factors for many disorders in the general population including ectodermal dysplasia, Ellis-van Creveld, and anencephaly. This review focuses on genetic disorders affecting monozygotic, dizygotic, and conjoined twins to gain a better understanding of them. Many studies focus on twins because they have a nearly identical genome, which eliminates environmental factors. In case studies, the concordance rates in monozygotic twins have supported that certain disorders were caused by genetics and not the environment. The discordant values in twins will also be evaluated briefly. Twinning studies have also shown linkages between specific disorders and the genes responsible for them. Knowing the location of these genes allows patients to be treated quickly and efficiently. This paper will discuss the possible causes of twinning and the various methods of identifying abnormalities in twins. These methods also allow preventive measures against the rise of birth defects during prenatal development. Epigenetics in twins is also viewed through the perspective of effects on them. Treatments for genetic disorders in twins are reviewed, ranging from the restoration of malformed teeth to the separation of conjoined twins. Support groups for twins in treatment, and their families are also briefly reviewed. Twins are truly fascinating from the time of separation of the embryo to birth; and still the complexity of twinning is not yet fully understood among the scientific world. Scientists have studied the human body from the time of prenatal development to birth, and still are in awe of the formation of twins. Research in twinning is ever more increasing in this field, leadi... ... middle of paper ... ...enetic and environmental influences on adult attention deficit hyperactivity disorder symptoms: a large Swedish population-based study of twins. Psychol. Med, 43 pp. 197-207. Mcgrogan, A., Franssen, C. F. and De Vries, C. S. 2011. The incidence of primary glomerulonephritis worldwide: a systematic review of the literature. Nephrology Dialysis Transplantation, 26 (2), pp. 414-430. Puttaraju, G. H. and Visveswariah, P. M. 2013. Ectodermal dysplasia in identical twins. Journal of pharmacy & bioallied sciences, 5 (Suppl 2), p. 150. Tokuhara, K., Hamada, Y., Yui, R., Tanano, A., Takada, K. and Kamiyama, Y. 2005. Congenital biliary dilatation in dizygotic twins. Pediatric surgery international, 21 (1), pp. 17-19. Van Den Berg, S. M. and Others. 2012. Genetic analysis of rare disorders: bayesian estimation of twin concordance rates. Behavior genetics, 42 (5), pp. 857-865.
Identical twins (monozygotic, MZ) develop from one single egg that has split into two. This makes them genetically identical. While MZ twins are genetically the same they may not have the same number of each gene which explains why one twin would be more susceptible to a disease than the other. Many MZ twins also share a placenta, however, one in three sets do not. A study done on MZ twin mice revealed that with different placentas one may be exposed to chemicals and even though the twins are genetically the same, due to the different exposure while in utero one was born with a different color fur. Perhaps one of the most interesting finding was of Jim Lewis and Jim Springer, MZ twins separated 27 days after birth who knew nothing of each other, until after 38 years of life, yet lived almost mirrored lives. This led to many more studies of identical twins separated at birth, many with similar
To completely understand the remainder of this essay, one must understand the difference between identical twins and fraternal twins. Twin zygosity is the genetic relationship of twins. There are two types of twins: monozygotic twins, also known as identical twins, and dizygotic twins, also known as fraternal twins. Identical twins have exactly identical DNA strands; they are same sex and they have very similar physical traits. They come from one egg that is fertilized by one sperm. Some time after conception, the egg splits resulting in two babies. Fraternal twins only have half identical DNA; that is, only one strand of the double-stranded DNA is the same. They come from two individual eggs that are fertilized by two individual sperms. They are either same sex or different sex, and are just like siblings of same parents born at different times. There are other kinds of twins as well; for example, "mirror-image twins," "polar body twins," and "half-identical twins." These names refer to the time that the egg splits in identical twins. This essay, however, will deal with only identical and fraternal twins (5). The question now is, Are identical twins allergic to the same things? Since identical twins have exactly identical DNA, the sharing of allergies can shed some light on the role of genetics in allergies.
There has been a main focus sexual orientation that is both scientific and a social interest to the public. Studies of monozygotic twins have been brought to whole different spectrum. Society would see them as the same, considering they have the same genes. Some wouldn’t think about twins having different sexual orientation such as being heterosexual or homosexual. There have been studies that suggested family factor has a substantial impact on sexual orientation on identical twins. There was a greater similarity in the monozygotic twins than in the dizygotic twins. It was also said that genes could be a factor to identical twins. Some argue that is not genetic that makes one twin a different sexual orientation than the other twin.
If you’ve ever seen two young siblings readily conversing in complete gibberish, you likely witnessed idioglossi, an autonomous language often created and shared between twins. With the increasing use of ultrasound scans, twins have been detected early in a pregnancy but have "vanished" according to subsequent ultrasounds. This phenomenon has been termed the vanishing twin syndrome and the cause is still not well known. They have been studied, analyzed, and written about for a long time in all cultures, yet there is still a great deal to learn both about multiples.
lorenzJm, H. G. (2014 feb 6). Evolving medical and surgical management of infants with trisomy 18. pubmed .
Imagine having a sibling always at your side, wake up on the morning to find your sibling lying next to you. Imagine that you have to do everything together, even siting on the same chair. Then one day the sibling being taken away from you. About one to every 70,000 to 100,000 people go through this. They are known to the world as conjoined twins. The way to treat those twin is undergo surgical separation. The surgical separation of conjoined twins is a delicate and risky procedure. Separating or not separating conjoined twins will affect the twins in many ways such as physical, ethical, and psychological aspect.
caused by an abnormal change in the TP63 Gene. Ectodermal Dysplasia can be inherited. If the ectodermal dysplasia is inherited in an autosomal dominant manner, the parent who is affected has a single copy of the abnormal gene and may pass it onto children. The child has a 50% chance of receiving it. There are over 180 ectodermal dysplasia recognized and named based on the specific combination symptoms shown in affected individuals. Each ectodermal dysplasia has its own combination of symptoms. When physicians consider an ectodermal dysplasia diagnosis, they examine your hair, nails, skin, sweat glands, and teeth.
There are many things about conjoined twins that people don’t know about. Conjoined twins are twins that are born together, so they share the same body. How that happens is when the egg only partially splits in half to form the babies. Next one of the major causes is that the egg doesn’t split until 13 – 15 days when it is usually 8-12 days. That means that the splitting process isn’t done when the overall process is done. Also, there are some symptoms for conjoined twins. One of them is when the uterus grows rapidly. All in all that is what conjoined twins are.
Rubinstein-Taybi Syndrome (RTS) is a rare condition characterized by, “distinctive facial features, broad and often angulated thumbs and great toes, short stature, and moderate to severe intellectual disability” (Stevens 2002). The syndrome was first described by Jack Herbert Rubinstein and Hooshang Taybi in the American Journal of Diseases of Children. In their initial article describing their findings, Rubinstein and Taybi described seven children, ages three to eight years old, who presented with “a constellation of congenital anomalies,” which they believed to represent a previously undescribed syndrome (Rubinstein and Taybi 1963). Other features associated with RTS, which tend to vary among affected individuals, include eye abnormalities, defects of the heart and kidneys, dental problems, and obesity (“Genetics Home Reference” 2007). While individuals with RTS often develop normally in-utero, they sometimes fail to thrive in the first few months of life as their height, weight, and head circumference percentiles begin rapidly declining (Stevens 2002). Another serious complication for infants with RBS is
In this world today twins are becoming more and more popular, as the number of births increases. Some say it's due to advance technology with invitro fertilization, or that woman are starting thier family later in life, and statistically women over the age of 35 have been linked to having multiple births. So the question rises, "How much do you really know on the subject twins?" Well as an Identical Twin myself, maybe I could give some light about us. You
Attention deficit hyperactivity disorder (ADHD) is one of the most common developmental disorders, according to research by Spencer and his colleagues (Spencer et al., 2007). Approximately 4-5% of college-aged students and adults experience ADHD (Kessler et al., 2006). Even though the general public has often perceived ADHD as an American cultural phenomenon, a study by Faraone has shown that ADHD prevalence in non-US countries at least matches ADHD prevalence in the US (Faraone, Sergeant, Gillberg, & Biederman, 2003). This finding demonstrates that ADHD has advanced into a serious problem not only in the US but around the world. As a result, the scientific community needs to address this issue. Too often, people have frequently
There are many different genetic disorders. I choosed down syndrome which is a very common genetic disorder. Down syndrome is caused by an extra copy of genetic material on all or part of the twenty first chromosomes. When someone or all of a person´s cells has an extra full, or partial, copy chromosomes twenty first, the result of down syndrome. There is two other name for down syndrome. That is trisomy Twenty first and there is trisomy G. Those are the first things you need to know about down syndrome.
Review how twins arise and how it might matter regarding the sharing or lack of sharing of the embryonic membranes and placenta
There is only 1 in every 10,000 people who have situs inversus. Situs inversus is a condition in which all the organs in the body are mirrored; the heart is on the right side, and the liver is on the left. Nineteen days into fetal development, the cilia, (hairlike structures), on the cell come to life. The flow of the cilia turns genes on/off, and tells them where to go. In individuals with situs inversus, the cilia didn't move at all, which "confused" the genes and triggred them to be reversed. Therefore, the left gene turned into a right gene, and vice versa. My thoughts on this situation are that although the condition is fatal for 30% of the embryos it happens to, the survivors sure have an interesting fact to tell.
When it comes to thinking about the experiment, it appears a little insane. The thoughts that run through people’s minds when they hear or read about twins or triplets being separated at birth is “Does the adoptive parents know?” “What person