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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[68]/47,XX,+mar1[19]/47,XX,+mar2[6]/46,XX[8]. 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.

We report on a pure duplication of the proximal chromosome 2q in a 6.5-year-old boy with V-shaped midline cleft palate and bifid uvula, posteriorly located tongue, and micrognathia (Pierre Robin sequence), celiac disease, failure to thrive, and developmental delay. Cytogenetic and FISH analysis indicated a duplication of chromosome 2q13-q22. In general, pure proximal duplication or triplication of 2q is rare. The clinical features and chromosomal breakpoints of the 10 previously reported patients varied, and no common phenotype or proximal duplication/triplication 2q syndrome could be defined to date. However, based on four previous patients with different orofacial clefts and our case, a locus for orofacial clefting may be located at proximal 2q. The duplication/triplication comprised chromosome 2q13 in all five affected individuals including our patient. Our patient and three previous cases (two with cleft palate only (CPO) and one with cleft lip/palate (CL/P)) showed a cytogenetic breakpoint at 2q13, which could support the presence of a critical dominant gene disrupted by a common breakpoint, however, the fifth case with CPO showed different breakpoints, advocating against the disruption of a critical dominant gene and supporting that the overexpression of a gene(s) on chromosome 2q13-q21 may cause cleft palate only (CPO) and Pierre Robin sequence. Hence, our findings support either the presence of one locus for orofacial clefting (CL/P, CPO, and Pierre Robin sequence) between markers D2S1897 (chromosome 2q12.2) and D2S2023 (chromosome 2q14.2), or alternatively the presence of a locus for CPO and Pierre Robin sequence on chromosome 2q13-q21., ((c) 2005 Wiley-Liss, Inc.)