Dictionary » C » Chromosome 13

Chromosome 13

Chromosome 13

Trisomy 13 or Patau syndrome is characterised by urogenital, cardiac, craniofacial, central nervous system and growth abnormalities. Defects include mental retardation, bilateral harelip and cleft palate, uni- or bilateral hexadactyly, growth retardation, polycystic kidney, ocular abnormalities, congenital heart disease and holoprosencephaly. Over 95% of human trisomy-13 conceptions spontaneously abort. Viable births rarely have prolonged survival. Approximately 80% of the cases involve free 13 trisomy. In 20% of the cases, either a mosaic or trisomy due to a translocation is involved. In cases of mosaicism, the severity of the clinical features can be diminished. A translocation, almost always t(13qDq) and more expressly t(13q14q), can occur de novo or can be transmitted by one of the parents. Rarely, more complex rearrangements are observed.

a number of observations of partial 13q trisomies are reported involving segments of variable length, with breakpoints occurring at different sites on 13q. One of the most frequent sites is the interface between q14 and q21. When the trisomy includes the q2 and q3 regions, it leads to a distinctive clinical syndrome. Facial dysmorphism resembles that of cornelia de lange syndrome. Respir 1000 atory distress and neonatal feeding difficulties are common. A small percentage of partial trisomies is due to de novo duplication.

The majority are the result of a malsegregation of a parental rearrangement (a reciprocal translocation or a pericentric inversion). Either total or partial monosomy 13q3 includes rings and terminal deletions and intercalary deletions which include band q14 and are accompanied by a retinoblastoma. The classical 13q- syndrome is associated with deletions in 13q32.

The most distinctive sign is the absence of a defined nasal bridge producing a greek profile. Microcephaly is often severe with brain malformations. Upper incisors set in a rabbitlike forward slant are highly characteristic. Hypoplasia or absence of the thumb, agenesis of the first metacarpal, fusion of the fourth and fifth metacarpals and syndactyly, eye malformations, bone and gi anomalies and considerable growth and mental retardation are frequently found. Deletions limited to bands more proximal to 13q32 are associated with growth retardation and moderate mental retardation, but not with major malformations. Deletions limited to bands distal to 13q32 have severe mental retardation without major malformations and usually without growth failure.

The characterization of 13q14 monosomy is justified by the existence of retinoblastoma. From the cytogenetic standpoint, this is a very heterogeneous group, with the deletion capable of extending on both sides of q14, from q11 to q22. The deletion usually occurs de novo 7c2

and can also result from a parental insertion. In ring 13, certain features of partial or complete 13 trisomy can be seen, due to partial duplication of the rings.

The study of patients afflicted with del(13)-retinoblastoma allowed the precise assignment of the gene for esterase D to 13q14.11. Other important genes on chromosome 13 include those for Wilson disease and propionyl CoA-carboxylase.


Please contribute to this project, if you have more information about this term feel free to edit this page



Results from our forum


Want to Buy Gleevec Online No Script, Gleevec On Dr Oz, San

... information on how to prevent pre-eclampsia medicine may cause false test results with copper sulfate urine sugar tests (e They can extra copy of chromosome 21 has various causes, including food poisoning due to infection drug dosage information Comprehensive in the Service is accurate, up-to-date, ...

See entire post
by Jeremy752
Thu Apr 10, 2014 6:43 am
 
Forum: Zoology Discussion
Topic: Want to Buy Gleevec Online No Script, Gleevec On Dr Oz, San
Replies: 0
Views: 2

Order Medrol Online Without Prescription, Medihaler-Epi Epin

... Alleroff cetirizine antihistamines Hay Fever Urticaria Avandamet is not recommended in patients with NYHA Class III and IV cardiac the in vitro chromosome Asthmahaler epinephrine adrenergic bronchodilators catecholamines vasopressors Adams-Stokes Syndrome Allergic Reactions Asthma, acute Asystole ...

See entire post
by Jeremy752
Thu Apr 10, 2014 6:27 am
 
Forum: Zoology Discussion
Topic: Order Medrol Online Without Prescription, Medihaler-Epi Epin
Replies: 0
Views: 1

Need some help with a question

In the cell cycle, at which stages do two chromatids make up one chromosome? (Can be multiple answers) a. beginning of mitosis b. end of G1 phase c. beginning of S (Synthesis) d. end of mitosis e. beginning of G2 phase

See entire post
by nillkill
Sat Mar 22, 2014 5:49 pm
 
Forum: Cell Biology
Topic: Need some help with a question
Replies: 0
Views: 200

Meiosis prophase I crossover

“Chromosomal crossover (or crossing over) is the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes.” http://en.wikipedia.org/wiki/Chromosomal_crossover Question: Due to the multiple layers of winding, how can parts of the ...

See entire post
by gs99
Fri Mar 07, 2014 9:23 pm
 
Forum: Molecular Biology
Topic: Meiosis prophase I crossover
Replies: 0
Views: 245

Re:

... (C, N) is 70 pm and smaller. That's 20-times less. However, you may be interested in the new one-molecule sequencing methods. And separation of chromosomes by dissection by laser is also nothing new. This is not a problem again. After scanning slices should not be necessary. http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=5292236&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F5238710%2F5292053%2F05292236.pdf%3Farnumber%3D5292236 ...

See entire post
by enarees
Wed Feb 26, 2014 6:57 pm
 
Forum: Microbiology
Topic: Slicing frozen chromosomes with lasers and scanning with SEM
Replies: 4
Views: 373
View all matching forum results

This page was last modified 21:16, 3 October 2005. This page has been accessed 2,341 times. 
What links here | Related changes | Permanent link