Replication error, a new hypothesis to explain the origin of a supernumerary marker chromosome in a mentally retarded boy.
A marker chromosome present in all the lymphocytes of a mentally retarded boy (47,XY,+mar) was identified. The karyotype of all fibroblasts was normal, 46,XY. His parents had normal karyotypes. The supernumerary marker chromosome was interpreted as a dicentric palindromic chromosome iso(9) (pter----q12, q12----pter). The marker chromosome may have originated through a ligation error in a replication fork during the S-phase followed by a new replication (endoreduplication).
Wik Sjöstedt
A
A
Alatalo
M
M
Wahlström
J
J
von Döbeln
U
U
Olegård
R
R
D002675:Child, Preschool; D002869:Chromosome Aberrations / Q000235:genetics*; D002899:Chromosomes, Human, Pair 9 / Q000648:ultrastructure; D004261:DNA Replication / Q000502:physiology; D005819:Genetic Markers; D006801:Humans; D007231:Infant, Newborn; D008607:Intellectual Disability / Q000235:genetics*; D007621:Karyotyping; D008297:Male
D005819:Genetic Markers