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Article and research paper on achondroplasia
Article and research paper on achondroplasia
Article and research paper on achondroplasia
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Achondroplasia (ACH) is the most common form of short-limb dwarfism occuring in 1 in 15,000 to 28,000 births and appears to be slightly more prevalent in females, but indiscriminent toward race (1-3). Evidence has been found in Egypt for cases of ACH dating back as far as 4500 B.C. (4). In simplest terms, ACH is a disease where the dwarfing of bones formed in the cartilage occurs (5). There are many features that accompany this disease including rhizomelic (proximal) shortening of the extremities, megalencephaly (enlarged brain), short stature, trident hand, and frontal bossing (prominent forehead) (1, 3, 4, 6-8). Expression of this gene at high levels is primarily found in cells of the nervous system and the cartilage rudiments and chondrocytes in the growth plates of developing bone (7, 9). Due to the fact that there are numerous types of skeletal dysplasia, some which appear similar to ACH at times, the only way for complete confirmation is to perform molecular techniques such as genetic testing (1, 4, 8).
The gene which is responsible for this disease, FGFR3, is located on chromosome 4 at 16.3, which is on the short arm near the telomere (4). Under normal circumstances, this gene forms fibroblast growth receptor 3 which interacts with a protein to begin a stream of signals that contribute to bone development and maintanence; it is also thought that this gene is also important in other tissue development (6, 7, 10-12). Some of the known pathways involved with FGFR3 are STAT1/3, STAT5, MEK1, ERK1, and MAP kinase signaling. Chondrogenesis and osteogenesis are two processes managed by these pathways and are greatly affected by a mutation (13-15). The sections of these pathways that involve and are affected by the mut...
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...s to interfere with bonding to the receptors. The final possibility uses CNP, which downregulates the activation in MAP kinase pathways in the chondrocytes (4).
ACH, is an interesting disease, one that after many years of research still remains a partial mystery. The fact that a single nucleotide on one chromosome can so greatly affect an individual is astounding, especially coupled with the fact that this mutation is so homogenious in genotype and phenotype. With more skeletal dysplasias being connected to FGFR3, research has increased to fully determine and define the pathways involved with this gene. Determining the reason for such a high mutation frequency and the link to paternal age are also being looked into. Once there is more understanding of how this mutation affects the body, treatments and possibly cures can be found for these individuals.
Fibrodysplasia ossificans progressiva also known as FOP is a one of the rarest, most disabling genetic bone conditions known to medicine. FOP causes muscles, tendons, ligaments, and other connective tissues to turn in to bone. Movement becomes limited in the affected areas of the body. People with FOP typically have malformed toes at birth, meaning the big toe is typically shorter than normal and abnormally turned outward in a position called a valgus deviation. Symptoms of FOP start to show up in early childhood. Most people with FOP develop painful tumor-like swellings also known as fibrous nodules. The fibrous nodules are visible on the neck, shoulders, and back.
In order to study the gene mutation that is supposed to cause Paget’s Bone Disease researchers had to have viable candidates to host the gene mutation. They found the best candidate to host the gene mutation in mice so they implanted the gene mutation in embryos of mice offspring. The researchers hypothesized that p62P394L is sufficient to induce PDB, especially since the p62 gene is responsible for encoding 62 kDa protein which functions in signaling osteoclast precursors. Results were found by fixing the first through fifth lumbar vertebra of four, eight, and twelve month old homozygote, heterozygote and WT littermates in 10% buffered formalin for 24- 48 hours. The first through fourth vertebra were then completely decalcified while the fifth was not. Longitudinal sections of both decalcified and undecalcified vertebra were cut, mounted on glass slides and stained to analyze. The mice with p62P394L had histologically normal bones, indicating that p62 mutation is not enough to induce Paget’s disease of the bone in vivo, there are additional factors necessary. Knowing osteitis deformas is due to hyper responsive multinucleated osteoclasts, it seemed a sensible suggestion. However, there are many other variables that should be factored when considering possible causes for osteoclast hyperformation. If p62P349L is present, doesn’t necessarily mean a person will get PDB, though an environmental factor such as measles could easily open up transduction pathways that could eventually lead to pagetic bone lesions. We find this study to be a stepping stone for future researchers to use in order to actually identify what causes Paget’s bone disease. (Hiruma, Kurihara, Subler, Zhou, Boykin, Zhang, Ishizuka, Dempster, Roodman & Wi...
ACHONDROPLASIA is known as being undersized, or less than 50in. in height. Having short limbs, a normal sized trunk, large head with a depressed nasal bridge and small face. This is a result of a disease in the thyroid gland. It can also be caused by Down syndrome or absorption, a cartilaginous tissue during the fetal stage. Hypochondroplasia, a mild form of dwarfism. Spinal tuberculosis and the deficiency of the pituitary gland secretions. Treatment with thyroxin or thyroid extract early in childhood results in normal growth and development. Somatrophin, also known as the human growth hormone is secreted by the anterior pituitary. Respiratory problems start to occur in infants. Symptoms of problems include snoring and sleeping with neck in a hyperextended condition. The limbs have rhizometic shortening. The legs are straight in infantry but when a child. He begins walking they develop a knock-knee position. When the child continues to walk legs begin to have a bowed-leg look. Occasionally, these curvatures are fixed. As the child continues to walk the kyphosis disappears and the back assumes a lordotic posture. If a delay in child’s walking occurs, the spine should be monitored closely for signs of gibbous formation. In infancy, hypercephalus can occur. Infants head circumference should be monitored close . Monthly checks of head circumference must be monitored. Radiologic studies are indicated if head circumference raises to disproportionately, or if symptoms of hydrocephalus. Child’s pediatrician should have a copy of head circumference curves for children with achondroplasia. Radiologic procedures for dwarfism include head ultrasound, C-T scan, or MRI of the head. If intervention is necessary, a ventriculoperitoneal shunt is placed relieving the pressure. Infants should also be monitored for foramen magnum compression. It is the opening at the base of the skull in which the brain stem and cervical spinal cord exit. When you have achondroplasia the foramen magnum is compressing the brain stem and spinal cord. Symptoms of narrowing include apnea the cessation of breathing and cervical myleopathy. C-T scans and MRI scans are done to examine the size of the infectious foramen magnum. A neurosurgical procedure called a foramen magnum decompression is executed to alarge foramen and alleviate further symptoms. Adolescents are at risk of getting lumbosacral spinal stenosis. The lumber spinal cord or nerve roots become compressed producing nerosurgical symptoms. Initial symptoms including weakness, tingling, and pain of the legs. Pain usually alleviated by assuming a squatting position.
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
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...
Congenital Adrenal Hyperplasia (CAH) is an inherited condition that affects hormone production in the adrenal gland. The individual lacks enzymes to make cortisol, and hormones are instead are shifted away to make other hormones, specifically androgens. This results in the deficiency of cortisol and the abundance of testosterone.
Marfan syndrome (MFS) is known as an autosomal dominant hereditary disorder of connective tissue. Connective tissue helps support all parts of the body. It also helps control how the body grows and develops. Principal manifestations involve the ocular, skeletal, and cardiovascular systems. MFS is caused by mutations in the glycoprotein gene fibrillin-1 (FBN1) which is located on chromosome 15(Marcheix, 2008). There are many mutations that can cause Marfan Syndrome, but most common are missense in that they are single-nucleotide changes that result in the substitution of a single letter that leads to a single amino acid change in the protein. The change in the amino acid alters the shape of the fibrillin proteins. The irregularly-shaped protein then assembles into irregularly shaped microfibrils. Fibrillin is a major element of microfibrils, which store a protein called transforming growth factor beta (TGF-β), a critical growth factor. TGF-β helps control the proliferation of cells, cell differentiation, cell movement, and apoptosis. Microfibrils help regulate the availability of TGF-β, which is deactivated when stored in microfibrils and activated when released. The increase in TGF-β and abnormalities involving microfibrils causes problems in connective tissues throughout the body such as malformations and disfigurements of the ligaments, spinal dura, lens zonules, and lung airways(Marcheix, 2008). The heart is also greatly negatively impacted through a weakening of the aortic wall, progressive aortic dilatation or aortic disjointing can occur because of strain caused by left ventricular contractions.
The human eye requires both rods and cones for normal vision. Over 100 million rods are located in the periphery of the human eye, and about 6 million cones compose the fovea. Rods, the more sensitive of the two to light, are not able to differentiate wavelengths, thus cannot detect color, and perceive shades of grey, black, and white. Cones, on the other hand, are of three types, containing particular pigments. They are categorized as red, blue, and green depending on to which wavelength they are most sensitive. These cones are what render color vision to humans.
Cystic fibrosis is one of the most common lethal mutations in humans. The autosomal recessive allele is carried by 1/20 Caucasians, 1/400 couples will have children with the disease, and ¼ children will be afflicted. If untreated, 95% of affected ch ildren will die before age five (Bell, 1996).
Achondroplasia is a genetic disorder in which there is a growth hormone deficiency, or there is a genetic mutation in either the father’s sperm or mother’s egg. Mayo Clinic, March 20, 2014. Achondroplasia was the first discovered in ancient Egyptian records. People with achondroplasia are considered people with supernatural powers. Many people call dwarfs midgets, but to them, it is very disrespectful because midget literally means little person.
Fractures are life-threatening to aged people having the metabolic bone disease OSTEOPOROSIS, in which bones become porous and brittle. A person, mostly women, having osteoporosis may break a hip during a fall and possibly die from complications. Birth Defects Congenital bone diseases constitute a wide spectrum, ranging from the unimportant--for instance, mild bow legs--to severe lesions, such as spina bifida, in which the lower end of the spine fails to develop properly and the baby is born with paralysis and misshapen vertebrae. Congenital diseases may have hormonal bases: for example, fibrous DYSPLASIA, in which fibrous tissue replaces that of some bones, often results in bone deformity; in addition, some girls with this disease physically mature so early that they are capable of pregnancy and childbirth at the age of seven.
Approximately one in three thousand children are born with this disorder and it does not progress over time. There does not appear to be any precedence as to sex or race and it is developed at conception. There are several types of Arthrogryposis which include Amyoplasia, Distal, Classic, and Syndromic. According to the Shriners hospitals for children, Amyoplasia is an overall lack of muscular development and growth with contracture, a loss of joint motion, and deformity of most joints. Babies with this type have dense fibrous tissue and fat instead of skeletal muscle. Distal affects several joints usually in the hands and feet, and range of motion may be slightly limited. Classic usually affects the hands, wrists, elbows, shoulders, hips, feet and knees with different degrees of severity. The most severe case can affect almost joint ...
Girls with this syndrome may have many middle ear infections during childhood; if not treated, these chronic infections could cause hearing loss. Up to the age of about 2 years, growth in height is approximately normal, but then it lags behind that of other girls. Greatly reduced growth in height of a female child should lead to a chromosome test if no diagnosis has already been made. Early diagnosis is very importance in order to be able to give enough correct information to the parents, and gradually to the child herself, so that she has the best possibilities for development. Early diagnosis is also important in case surgical treatment of the congenital heart defect (seen in about 20 per cent of cases) is indicated.
There are many different types of dwarfism that researchers have confirmed today, but there still are many genes for dwarfism that remain unidentified.The most common of these known causes is achondroplasia, a bone growth disorder.The Little People Online website states that most dwarfs who suffer from achondroplasia are born to “average-size” parents, and that their birth rate is somewhere between onein26,000-40,000www.lpaonline.org).The main characteristics of this form of dwarfism are normal trunk size with short appendages, irregularly large heads wi...