Figure 1
Figure 1. Family pedigree, hematologic data, and schematic representation of the telomeric region of paternal and maternal chromosome 16 (p16.3). The common deletion or nondeletion defects in the proband and in his parents, and the presence of hyper-unstable alpha-globin variants were excluded with conventional DNA analysis technique (GAP-PCR and alpha-gene sequencing). Multiplex ligation-dependent probe amplification (MLPA) of the extended alpha-globin gene cluster using a set of 25 probes covering a region of 170 kb in the alpha-cluster (MRC-Holland)4 detected the deletion of the 2 MCS-R2 region probes (coordinates ligation site 103553-54 and 103712-13, respectively) in homozygosity in the proband, suggesting the complete lack of MCS-R2 region, and in heterozygosity in his parents. In the proband and in his father, MLPA analysis revealed a deletion extending up to the first telomeric probe (coordinates ligation site 43321-22), located on POL3K gene, suggesting the removal of the telomere.10 Family segregation studies of SNPs along the telomeric region of chromosome 16 (coordinates from 41263 to 127429, according GenBank accession number AE006462.1) showed in the father an apparent homozygosity and absence of Mendelian segregation for rs216590 (coord 41263) and for rs2238368 (coord 110328) polymorphisms, whereas the rs2562189 (coord 127429) was heterozygous. These data are indicative of a deletion extending at least from the telomere to rs2238368 (coord 110328), which caused the loss of MCS-R1, MCS-R2, and MCS-R3 regions. We could not define the centromeric breakpoint of the deletion. The same deletion was identified in the paternal grandmother. In the mother, heterozygosity for rs12927713 (coord 92220) and rs22388368 (coord 110328) suggested a smaller deletion. The direct sequencing of the rearranged fragment, obtained with a GAP-PCR using 2 primers flanking the deletion, allowed us to exactly define the extension (3361 bp), the breakpoints (5′ at 103192/3 and 3′ at 106553/4 position), and the presence of 39 orphan nucleotides.

Family pedigree, hematologic data, and schematic representation of the telomeric region of paternal and maternal chromosome 16 (p16.3). The common deletion or nondeletion defects in the proband and in his parents, and the presence of hyper-unstable alpha-globin variants were excluded with conventional DNA analysis technique (GAP-PCR and alpha-gene sequencing). Multiplex ligation-dependent probe amplification (MLPA) of the extended alpha-globin gene cluster using a set of 25 probes covering a region of 170 kb in the alpha-cluster (MRC-Holland)4  detected the deletion of the 2 MCS-R2 region probes (coordinates ligation site 103553-54 and 103712-13, respectively) in homozygosity in the proband, suggesting the complete lack of MCS-R2 region, and in heterozygosity in his parents. In the proband and in his father, MLPA analysis revealed a deletion extending up to the first telomeric probe (coordinates ligation site 43321-22), located on POL3K gene, suggesting the removal of the telomere.10  Family segregation studies of SNPs along the telomeric region of chromosome 16 (coordinates from 41263 to 127429, according GenBank accession number AE006462.1) showed in the father an apparent homozygosity and absence of Mendelian segregation for rs216590 (coord 41263) and for rs2238368 (coord 110328) polymorphisms, whereas the rs2562189 (coord 127429) was heterozygous. These data are indicative of a deletion extending at least from the telomere to rs2238368 (coord 110328), which caused the loss of MCS-R1, MCS-R2, and MCS-R3 regions. We could not define the centromeric breakpoint of the deletion. The same deletion was identified in the paternal grandmother. In the mother, heterozygosity for rs12927713 (coord 92220) and rs22388368 (coord 110328) suggested a smaller deletion. The direct sequencing of the rearranged fragment, obtained with a GAP-PCR using 2 primers flanking the deletion, allowed us to exactly define the extension (3361 bp), the breakpoints (5′ at 103192/3 and 3′ at 106553/4 position), and the presence of 39 orphan nucleotides.

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