Characterization of two supernumerary marker chromosomes in a patient with signs of Klinefelter syndrome, mild facial anomalies, and severe speech delay.Am J Med Genet A 2006; 140(5):488-95AJ
A boy with signs of Klinefelter syndrome, mild facial dysmorphic features, and severely retarded speech development displayed a female karyotype with mosaicism for two marker chromosomes 48,XX,+mar1,+mar2/47,XX,+mar1/47,XX,+mar2/46,XX. Using chromosomal microdissection, locus-specific fluorescence in situ hybridization (FISH), and PCR with several Y-chromosome markers, the larger supernumerary marker chromosome (SMC) was characterized as a ring Y-chromosome. Detection of the SRY-region explained the male phenotype. The smaller second marker chromosome contained the pericentromeric region of chromosome 8. We suggest that the co-occurrence of a partial Y-chromosome and partial trisomy 8 explain the severe speech delay and the facial dysmorphic features.