RT Book, Section
A1 Mellado, Cecilia
A1 Sahin, Mustafa
A2 Rudolph, Colin D.
A2 Rudolph, Abraham M.
A2 Lister, George E.
A2 First, Lewis R.
A2 Gershon, Anne A.
SR Print(0)
ID 7059251
T1 Chapter 575. Rett Syndrome (Mecp2-Related Disorders)
T2 Rudolph's Pediatrics, 22e
YR 2011
FD 2011
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-149723-7
LK accesspediatrics.mhmedical.com/content.aspx?aid=7059251
RD 2024/04/16
AB Rett  syndrome  (RTT)  is  an  X-linked  dominant  neurodevelopmental  disorder  and  affects  mainly  females.  The  prevalence  is  1  in  10,000  girls  by  the  age  of  12,1  making  it  one  of  the  most  common  genetic  causes  of  severe  cognitive  impairment  in  girls.  RTT  is  caused  by  mutations  in  the  MECP2  gene  located  at  Xq28.  MECP2  encodes  a  nuclear  protein  (MeCP2)  that  binds  methylated  DNA.  The  function  of  MeCP2  protein  has  not  been  fully  elucidated;  it  is  thought  to  mediate  transcriptional  silencing  and  epigenetic  regulation  of  genes  in  regions  of  methylated  DNA  through  its  association  with  5-methylcytosine–rich  heterochromatin  and  may  play  a  role  in  modulation  of  RNA  splicing  as  well.2  There  are  different  levels  of  expression  depending  on  the  tissue  and  developmental  stage.  Mutations  in  MECP2  can  result  in  a  similar  constellation  of  neuropsychiatric  abnormalities  with  either  gain  or  loss  of  protein  function.  For  example,  MECP2  duplications  have  been  reported  in  males  with  severe  cognitive  impairment.