A transmitted deletion of 2q13 to 2q14.1 causes no phenotypic abnormalities

Fluorescence in situ hybridization characterization of apparently balanced translocation reveals cryptic complex chromosomal rearrangements with unexpected level of complexity

“…Deletions and other chromosomal abnormalities have been reported not to have any association with any phenotypic effect. 17 To date, asymptomatic transmitted deletions of at least nine distinct regions of the human genome have been reported. 17 This study also emphasizes the need to combine high resolution G-banding with different FISH methodologies.…”

Recurrent copy number changes in mentally retarded children harbour genes involved in cellular localization and the glutamate receptor complex

“…Techniques allowing the detection of submicroscopic segmental aneuploidy have enabled us to pinpoint novel microdeletion and microduplication syndromes, such as CHARGE (coloboma, heart anomalies, chonal atresia, retardation, genital and ear anomalies), 5 Peters Plus, 6 recurrent 17q12 rearrangements, 7 del(17)(q21), 8,9 and the 22q13.3 deletion, 10 Pitt-Hopkins 11 and thrombocytopenia-absentradius syndromes 12 (for reviews see Lee and Lupski 3 and Slavotinek 13 ). In addition, clinically inconsequential segmental deletions [14][15][16] and segmental duplications in healthy individuals 17 have been reported. Studies involving array-based comparative genome hybridization (array-CGH), 18,19 representational oligonucleotide microarray analysis, 20 fosmid library insert mapping 21 and SNP inheritance analyses [22][23][24] indicate that copy number changes (CNCs) are frequently occurring polymorphisms in the genome of healthy individuals.…”

Deletions of 2q14 that include the homeobox engrailed 1 (EN1) transcription factor are compatible with a normal phenotype

“…Here, we present further examples of an affected boy with the same 2 -3 Mb deletion of 2q14.1 -q14.2 as his unaffected father and brother. This deletion overlapped with a previous transmitted deletion of 2q13 -q14.1 in a phenotypically normal mother and daughter 7 which has now been mapped in more detail.…”

“…The same deletion was found in her mother who had two children and no history of miscarriages. 7 YACs 786a12 and 817b4 were deleted, 791f4 partially deleted and the deletion estimated at 4.5 -6.0 Mb. In order to test the hypothesis that this deletion was the same as that in family 1, we remapped the deletion and found seven clones were deleted ( Table 1).…”

“…The proband in family 2 had been ascertained for miscarriages, 7 but it is difficult to see how these could have been caused by a deletion that is compatible with a normal phenotype, especially when the carrier mother had no miscarriages herself and most simple deletions are transmitted without causing additional imbalances. 6 These deletions are immediately adjacent to the site at which the ancestral great ape chromosomes 2A and 2B fused to produce human chromosome 2.…”