Presumptive monosomy 21 with neuronal migration disorder re-diagnosed as de novo unbalanced translocation t(18p;21q) by fluorescence in situ hybridisation.
We present clinical and cytogenetic data of a one year old boy with partial monosomy for both 21q and 18p, resulting from a de novo unbalanced translocation. The initial diagnosis of a seemingly full monosomy 21 was revised after fluorescence in situ hybridisation (FISH) with whole chromosome painting probes and a locus-specific chromosome 21 probe. The karyotype was reinterpreted as 45,XY,der(18)t(18;21)(p11.2;q22.1),-21. This karyotype, to our knowledge, has not been previously described. The boy presented with a spectrum of clinical features previously described for (partial) monosomy 18p only, for monosomy 21q only, or for both of these aneusomies. The radiological finding of a neuronal migration disorder with localised polymicrogyria (cortical dysplasia) has not been described for either monosomy before.
Alkan
M
M
Department of Paediatrics, Inselspital, and Institute of Pathology, University of Bern, Switzerland.
Ramelli
G P
GP
Hirsiger
H
H
Keser
I
I
Remonda
L
L
Bühler
E M
EM
Moser
H
H
D000015:Abnormalities, Multiple / Q000235:genetics; D002465:Cell Movement / Q000235:genetics*; D002540:Cerebral Cortex / Q000473:pathology; D002887:Chromosomes, Human, Pair 18; D002891:Chromosomes, Human, Pair 21; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D007621:Karyotyping; D008279:Magnetic Resonance Imaging; D008297:Male; D009006:Monosomy / Q000235:genetics*; D009474:Neurons / Q000166:cytology*; D014178:Translocation, Genetic