Detailed molecular and clinical investigation of a child with a partial deletion of chromosome 11 (Jacobsen syndrome)

Abstract

Background: Jacobsen syndrome (JBS) is a rare chromosomal disorder leading to multiple physical and mental impairment. This syndrome is caused by a partial deletion of chromosome 11, especially subband 11q24.1 has been proven to be involved. Clinical cases may easily escape diagnosis, however pancytopenia or thrombocytopenia may be indicative for JBS.

Results: We report a 7.5 years old boy presenting with speech development delay, hearing impairment and abnormal platelet function. High resolution SNP oligonucleotide microarray analysis revealed a terminal deletion of 11.4 Mb in size, in the area 11q24.1-11qter. This specific deletion encompasses around 170 genes. Other molecular techniques such as fluorescence in situ hybridization and multiplex ligation-dependent probe amplification were used to confirm the array-result.

Discussion: Our results suggest that the identification and detailed analysis of similar patients with abnormal platelet function and otherwise mild clinical features will contribute to identification of more patients with 11q deletion and JBS.

Figure 1

A. SNP Oligonucleotide Microarray Analysis (SOMA) identifies the deletion in the long arm of chromosome 11. The deleted segment on chromosome 11 lies between marker SNP_A-2122040 at chr11: 123073531 and marker SNP_A-2246844 at chr11: 134449982, spanning an area of 11.37 Mb. B. Partial karyotype of chromosomes 11 of the proband. Arrow shows the deleted chromosome segment.