AUTOSOMAL Aberrations CRISTOBAL, Erica Joyce B. JARABE, Renee Beatriz P. AAPD2B
UNIT V. Human Chromosomes and Chromosome BehaviorOBJECTIVES At the end of the unit, the students should be able to: 1. Understand the importance of human karyotyping 2. Characterize individuals with sex chromosome aberrations 3. Differentiate the types of autosomal aberrations, and 4. Illustrate and explain the different structural abnormalities
CHROMOSOMAL ABERRATIONS / ABNORMALITIES *** *It is the disruptions in the normal chromosomal content of a cell. *Originates as a result of an error during meiosis (Non- Disjunction), specifically in ANAPHASE stage. ***
Wolf-Hirschhorn Syndrome (WHS) , alsoknown as Pitt-Rogers-Danks Syndrome or PittSyndrome ----- was first described in 1961 byAmericans Herbert L. Cooper and Kurt Hirschhornand thereafter, gained worldwide attetion bypublications by the German Ulrich Wolf andHirschhorn, Humangenetik a German scientificmagazine. DELETION of the short arm of chromosome 4.
CRI DU CHAT also known as chromosome 5pdeletion syndrome, 5p minus syndrome or Lejeune’ssyndrome. *Is a rare genetic disorder due to a missing partof chromosome 5. Its name is a French term (cat-cryor call of the cat) referring to the characteristic cat-like cry of affected children. *It was first described by Jerome Lejeune in1963. The condition affects an 1 in 50,000 livebirths, strikes all ethnicities, and is more common infemales by a 4:3 ratio. DELETION on the short arm of chromosome 5. Cries like a CAT
Physical Characteristics *Excessive Drooling *Behavioral Problems *Often Mental Retarded *Exhibits Gastorintestinal and Cardiac Complications *Abnormal Development of Larynx and Glottis
Jacobsen’s Syndrome also known as 11q deletiondisorder, is a rare congenital disorder resulting fromdeletion of a terminal region of chromosome 11 thatincludes band 11q24.1. *It can cause intellectual disabilities, a distinctivefacial appearance, and a variety of physical problemsincluding heart defects and a bleeding disorder. *The syndrome was first identified by Danishphysician Petra Jacobsen, and is believed to occur inapproximately 1 out of every 100,000 births. is a condition caused by the DELETION of a terminalregion of chromosome 11.
Physical Characteristics*Bleeding Disorder*Heart Defects*Wide Set Eyes*Low Set Misshapen Ears*Large Toes
Pallister-Killian Syndrome also known asTetrasomy 12p Mosaicism or Pallister MosaicAneuplody Syndrome. Is an extremely rare genetic disorder occurring inhumans. Pallister-Killian occurs due to the presence ofthe anomalous extra isochromosome 12p, the short armof the twelfth chromosome. This leads to the development of Tetrasomy 12p.Because not all cells have the extraisochromosome, Pallister-Killian is a mosaic condition. TETRASOMY in the smaller arm of chromosome 12. 2n+2 or 48 chromosomes
Patau Sundrome, also known as Trisomy 13 andTrisomy D. *Is a chromosomal abnormality, a syndrome inwhich a patient had an additional chromosome 13 due tonon-disjunction of chromosomes during meiosis. Someare caused by Robertsonian Translocations. The extrachromosome 13 disrupts the normal course ofdevelopment, causing heart and kidney defects, amongstother features characteristic of Patau syndrome. *Patau syndrome affects somewhere between 1 in10,000 and 1 in 21,700 live births. TRISOMIC in the chromosome 13. 47 chromosomes
Isodicentric chromosome 15 is the scientificname for a specific type of chromosome abnormality.Individuals with isodicentric chromosome 15, or"idic(15)", have 47 chromosomes instead of the typical46 chromosomes. With extra genetic material in chromosome 15. 47 chromosomes
Physical Characteristics *Epicanthal Folds in the Eye *Short Stature *Delayed Language Development *Seizures *Some are Mentally Retarded
Edward’s Syndrome also kwnon as Trisomy 18(T18) or Trisome E. *It is a genetic disorder caused by the presence ofall of an extra 18th chromosome (Trisomy 18). *It is named after John H. Edwards, who firstdescribed the syndrome in 1960. It is the second mostcommon autosomal trisomy, after Down Syndrome, thatcarries to term. *Edward’s Syndrome occurs in around one in6,000 live births and around 80 % of those affected arefemale.
Down Syndrome also known as Trisomy 21, is achromosomal condition caused by the presence of all orpart of an extra 21st chromosome. It is named after JohnLangdon Down, the British physician who describedthe syndrome in 1866. The condition was clinicallydescribed earlier in the 19th century by Jean EtienneDominique Esquirol in 1838 and Edouard Seguin in1844. Down syndrome was identified as a chromosome21Trisomy by Dr. Jerome Lejeune in 1959. *The average IQ of children with Down syndromeis around 50, compared to normal children with an IQ of100. With extra genetic material in chromosome 15. 47 chromosomes
Physical Characteristics*Epicanthal Folds in the Eye*Short Stature*Delayed Language Development*Seizures*Some are Mentally Retarded
Cat Eye Syndrome is a rare condition causedby the short arm (p) and a small section of the longarm (q) of human Chromosome 22 being present three(trisomic) or four times (tetrasomic) instead of theusual two times. *The term "Cat Eye" syndrome was coinedbecause of the particular appearance of thevertical colobomas in the eyes of some patients.However, over half of the CES patients in theliterature do not present with this trait. *There is no significant reduction in lifeexpectancy in patients who are not afflicted with oneof CES life threatening abnormalities.
Physical Characteristics *Iris Coloboma *Slant Opening of the Eyelids *Abnormal Obstruction of the Anus *Scoliosis *Hernias