Trisomy 8 syndrome owing to isodicentric 8p chromosomes: regional assignment of a presumptive gene involved in corpus callosum development.
Two patients with trisomy 8 syndrome owing to an isodicentric 8p;8p chromosome are described. Case 1 had a 46,XX/46,XX,-8,+idic(8)(p23) karyotype while case 2, a male, had the same abnormal karyotype without evidence of mosaicism. In situ hybridisation, performed in case 1, showed that the isochromosome was asymmetrical. Agenesis of the corpus callosum (ACC), which is a feature of trisomy 8 syndrome, was found in both patients. Although ACC is associated with aneuploidies for different chromosomes, a review of published reports indicates that, when associated with chromosome 8, this defect is the result of duplication of a gene located within 8p21-pter. Molecular analysis in one of our patients led us to exclude the distal 23 Mb of 8p from this ACC region.
Dipartimento di Genetica Medica, IRCCS Ospedale Bambin Gesù, Roma, Italy.
M C
MC
Digilio
A
A
Giannotti
G
G
Floridia
F
F
Uccellatore
R
R
Mingarelli
C
C
Danesino
B
B
Dallapiccola
O
O
Zuffardi
D000015:Abnormalities, Multiple / Q000235:genetics*; D061085:Agenesis of Corpus Callosum; D002869:Chromosome Aberrations / Q000235:genetics*; D025063:Chromosome Disorders; D002874:Chromosome Mapping; D002898:Chromosomes, Human, Pair 8; D005260:Female; D006330:Heart Defects, Congenital / Q000235:genetics; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009030:Mosaicism; D013577:Syndrome; D014314:Trisomy