Chromosome 15

Angelman Syndrome (AS) is a genetic disorder of the ubiquitin-protein ligase E3A or UBE3A on the 15th chromosome. If this is gene damaged or lacks the maternal allele for UBE3A contributions, it results in Angelman Syndrome (Mary 2011). This disorder was first discovered in 1965 by an English pediatrician known as Dr. Henry Angelman. Angelman studied children with similar motor disorders, facial abnormalities and a happy demeanor. He named this disorder "Happy Puppet Syndrome" after observing a painting by Giovanni Francesco Caroto named “A Boy with a Puppet”. By 1982, researchers at the University of Florida studied this disease more and compared it to Angelman research, renaming it Angelman Syndrome. It was not till 1997, that the cause of it was discovered to be a mutation in the UBE3A gene by Dr. Joseph Wagstaff and Dr. Arthur Beaudet (Tiranoff, 2003).…

syndrome is not an inherited disease, and is instead caused by a change in the E3 ubiquitin protein ligase gene (UBE3A) on the maternal chromosome 15. This change prevents the chromosome from functioning properly. It occurs as a random event during the formation of eggs and sperm, or in the early stages of embryonic development. There are four distinctive causes for Angelman syndrome, and each of those causes can be determined by genetic testing. All four causes produce the same syndrome,…

Usher syndrome is an orphan disease that is extremely common, but is often swept under the rug. It is an inherited disorder that appears in mostly children at a young age and is the most frequent cause of deaf-blindness in humans. It is characterized by hearing impairment that leads to total deafness along with progressive vision loss. There are four levels of Usher Syndrome, Usher Type I, Usher Type II, Usher Type III, and Usher Type IV. Usher Type II is the most common type of Usher Syndrome.…

In 1965 Harry Angelman reported clinical findings in three children with similar, unusual, attributes. These children had what was known as “happy puppet” syndrome, but was later changed to Angelman syndrome, due to its pejorative name. Angelman syndrome is a neurodevelopmental disorder distinguished by: severe learning difficulties, ataxia, jerky movements, epilepsy, speech impairments, hypopigmentation in the hair and the skin with blue eyes, subtle dysmorphic facial features, and happy and…

Trisomy 21 is caused by the failure of the chromosome 21 to separate during sperm or egg development. As a result of this, a sperm or egg is produced with an extra chromosome 21. When it is combined with the other normal cell, the baby has 47 chromosomes out of which 3 are chromosomes 21. In 88% of the cases, trisomy 21 arises from the non-separation of the chromosomes in the mother, 8% from the non-separation of the father and only 3% when the egg and the sperm have merged together to form one.…

Prader-Willi syndrome is a genomic imprinting disorder caused by the failure to express SNRPN (small nuclear ribonucleoprotein-associated polypeptide N) gene product. SNRPN is expressed only on the paternal chromosome 15q11-q13, however, the exact genes responsible for Prader-Willi syndrome haven't been identified. People normally inherit one copy of chromosome 15 from each parent. Some genes are active only on the copy that is inherited from a person's father, the paternal copy. Genomic…

Down syndrome is a mutation that occurs when an individual has a partial or full extra copy of chromosome 21. The additional chromosome changes the course of development and causes the well known characteristic changes associated with down syndrome. A few of the common physical traits of down syndrome are small stature, low muscle tone, and an upward slant to the eyes. However, each person affected with down syndrome is unique and may possess these characteristics to different levels. Down…

DEFINCIENCY OF ENZYME beta- hexosaminidase A CAN CAUSE TAY-SACHS DISEASE DEFINITION: Tay-sachs disease is a rare genetic disorder found commonly in isolated genetic such as Jewish Population. This is also known as a fatal genetic lipid storage disorder in which harmful quantities of cell membrane components named ganglioside accumulate in the brain stem cells, eventually leading to the premature death of cells. II. SYMPTOMS: Diagnosis can be confirmed either by enzyme analysis or mutation…

of the short arm, known as the p arm on chromosome 5 (1). This disease was first described in 1963 by a French geneticist, Jerome Lejeune as a hereditary congenital syndrome (1). Today, it is known as one of most frequent autosomal deletion syndromes that results from loss of the distal portion of chromosome 5 affecting the telomerase reverse transcriptase (TERT) gene (6). The deletion occurs at random during meiosis or early fetal development and varies in level of severity dependent upon the…

Meiosis is the dividing of cells as the embryo develops in the womb, as stated in the Pearson Anatomy & Physiology edition 10. It starts the haploid division of gametes that further develops the embryo into a fetus and then into a fully functional baby within nine months. This form of cell replication creates four daughter cells that have only half of the amount of chromosomes that are contained within a human body, 23 instead of 46. Within the book it explains that meiosis goes through…