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.
Digilio
M C
MC
Dipartimento di Genetica Medica, IRCCS Ospedale Bambin Gesù, Roma, Italy.
Giannotti
A
A
Floridia
G
G
Uccellatore
F
F
Mingarelli
R
R
Danesino
C
C
Dallapiccola
B
B
Zuffardi
O
O
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