Polydactyly is the most commonly observed congenital digital anomaly of the hands and feet appearing in 1 in every 500 live births. The condition is characterized by an abnormal amount of digits per hand in which the extra digits may develop bilaterally, or it may occur on both or just one hand, foot, or some other combination. Usually the extra digits that develop are either small pieces of soft tissue or fully formed in appearance. It is noted that in around 80% to 90% of cases involve the peripheral digits, although it is possible that all digits may be affected. Depending on the location of the extra digit, polydactyly can be further classified into three types: pre-, post-, and central axial forms. Polydactyly can occur as an isolated disorder (non-syndromic) or alongside other symptoms or disease. Isolated polydactyly is typically caused by the inheritance of an autosomal dominant gene mutation, meaning the cause is not due to a multifactorial trait. However, most cases of polydactylism are linked to specific syndromes that cause congenital anomalies through a variety of gene mutations.
Genetic research has linked the cause of two types of polydactylism, post-axial and pre-axial, to several gene mutations. One particular example is a frameshift mutation in the GLI3 gene on chromosome 7. GLI3 stands for GLI family zinc finger 3 and it is a transcription factor that is vital for proper early development, since it plays a role in the patterning of tissues and organs during embryonic development. Therefore, many congenital anomalies, such as polydactyly, can be linked to the improper expression of this gene.
Post-axial polydactyly (PAP) is characterized by the development of an extra digit adjacent to the pinky finger or toe...
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... at the base of the pedicle. This would clearly be preferable to performing surgery, but may be more applicable in cases of type B than type A polydactyly. Of a total of 21 cases which were examined, this procedure resulted in a slight complication in only one case, where the digit had to be removed surgically due to failure of removal by suture ligation. The only real side effect of this simple treatment is that there was found to be a small bump remaining at the site in 43 percent of cases.
Although there has been some work into the genetic basis of polydactyly, advances in examination of the human genome may create a better understanding of the condition in the future. A large amount of the work done so far has been focused on animal models, and there is still room for further work to discover the genetic basis of the different types of polydactyly in humans.
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.
Throughout this semester, I have gained a abundance of information on genetics that I never knew, but reading the book "Mendel 's Dwarf" did make it a little bit more difficult for me to understand genetics. After looking back at my notes I remembered early in the semester our professor discussing the condition that Dr. Benedict Lambert suffers from which is Achondroplasia(dwarfism). Achondroplasia is condition of short limbs, usually in arms and legs, the torso and head size is majority of the time normal. Simon Mawer describe Dr. Lambert body as "His body is not normal, his is not normal, his limbs are not normal. He possesses a massive forehead and blunt, puglike features. His nose is stove in at the bridge, his mouth and jaw protrude. His
The two different alleles present in the could be due to the effect of evolution and natural selection because the same can be found in chimps.4 The PV92 locus does not code for any protein but rather involves an Alu element that is 300-bp long. A person with the “+” allele would have the Alu element, making that sequence longer while those with the “-“ allele don’t have the element and would have a shorter sequence. This locus can be found on chromosome 16.3 There are multiple Alu sequences found among primate genomes but there are human specific sequences such as the one found on the PV92 locus.1 In the experiment, student DNA was collected from cheek cells and PCR was used to target the loci and amplify the region of DNA. In the taster gene, after amplification, a restriction digest was performed to differentiate between the two alleles. The digest was able to show differentiation because those with the “T” allele would have two bands from gel electrophoresis and those with “t” would have one band because the restriction enzyme doesn’t cut it.
Cagli NA, Hakki SS, Dursun R, et al. (Dec 2005). "Clinical, genetic, and biochemical findings in two siblings with Papillon-Lefèvre Syndrome". J. Periodontol. 76 (12): 2322–2329. doi:10.1902/jop.2005.76.12.2322. PMID 16332247
-Reilly Philip. Is It In Your Genes. Cold Spring Harbor Laboratory Press. 2004: 223-228. Print
Ivy is the third generation in her family to be affected by achondroplasia. Her grandfather, her father, and her brother also have it. Achondroplasia is inherited as an autosomal dominant trait whereby only a single copy of the abnormal gene is required to cause achondroplasia. Nobody with the mutated gene can escape having achondroplasia. Many individuals with achondroplasia have normal parents, though. In this case, the genetic disorder would be caused by a de novo gene mutation. De novo gene mutations are associated with advanced paternal age, often defined as over age 35 years. If an individual with achondroplasia produce offspring with a normal individual, the chances of the offspring inheriting the mutant allele achondroplasia is 50%. If both of the parents have achondroplasia, the chances that their offspring will be of normal stature a...
(Binder, 386). Other collagen-containing extraskeletal tissues, such as the sclerae, the teeth, and the heart valves are also affected to a variable degree. OI has a "common feature of bony fragility associated with defective formation of collagen by osteoblasts and fibroblasts." (Smith, 1983, 13) This disease, involving defective development of the connective tissues, is usually the result of the autosomal dominant gene, but can also be the result of the autosomal recessive gene. Spontaneous mutations are common and the clinical presentation of the disease remains to be quite broad. (Binder, 386)
Currently, the limitations on research are too restricting, as researchers are limited to resources already gathered. There are sixty existing stem cell lines today, already derived from embryos. Researchers are to only use these lines. These limitations severely hinder stem cell research. The government, especially President Bush, should re-evaluate stem cell research.
Francis S. Collins is a renowned geneticist who originally became Ph.D in Physical Chemistry at Yale University and later on, a Medical Doctor at University of North Carolina. As soon as he graduated he was offered a fellowship in Human Genetics at Yale University under the guidance of Sherman Weissman, currently Sterling Professor of Genetics. In the late 1980’s Collins became known in the field of Medical Genetics for his development of positional cloning, a technique that allows to locate a hereditary disease-causing gene by studying the inheritance pattern within a family. Working with his method researchers found the genes responsible for diseases like Cystic fibrosis, Huntington’s disease, Neurofibromatosis, Multiple Endocrine Neoplasia type one, and Hutchinson-Gilford Progeria Syndrome. In 1993 Dr. Collins succeeded Dr. James D. Watson as the director of the National Human Genome Research Institute (NHGRI), overseeing the role of the United States in the mapping of the human genome. In 2009 President Obama personally recommended Collins to lead the National Institute of Health (NIH) where he works until present day. Francis S. Collins is by no means a bragging individual, bits and pieces of his accomplishments are scattered throughout the book and he makes no big deal about it; instead he j...
About one out of every 10,000 to 100,000 births, a child is born with the birth defect: Poland Syndrome or Poland Anomaly. The birth defect can be apparent from either birth or adolescence depending on ...
Congenital defects also may have genetic bases, as in families who have extra fingers or toes or in the disease osteogenesis imperfecta, in which children have such brittle bones that many are fractured. Disorders of growth and development include several kinds of dwarfism and gigantism. Bones or limbs may develop deformity as the result of known causes, such as the infection poliomyelitis, or unknown or variable causes, such as curvature of the spine (SCOLIOSIS) or CLUBFOOT. Infections Infections of bone, called osteomyelitis, are usually caused by pus-producing bacteria, especially Staphylococcus and Streptococcus.
In addition, research for this project enabled me to identify five essential elements for acquiring cross cultural competency which I will use as guidelines in conflict resolution in my future occupation:
...omosomes or genetic/chromosomal disorders. The most common type of genetic or chromosomal disorder is Down Syndrome or trisomy 21 (Cherry, n.d.). The condition occurs when a child has three chromosomes at the site of the twenty-first chromosome rather than the normal two. Some of the most common signs of Down Syndrome include round face, thick tongue, slanted eyes, hearing problems, heart defects, and intellectual impairment.
Technology has had a great impact on society when it comes to medicine. Medical technology has been around since the cave man began using rocks as tools to perform trephening. Since then there has been many new advancements in medicine due to technology. From painless needles to robots used for surgeries technology is around to stay.