Increased first-trimester nuchal translucency associated with a dicentric chromosome and 9q34.3 microdeletion syndrome

We present prenatal diagnosis and chromosomal microarray analysis (CMA) of 9q34.3 microdeletion in a foetus with an increased nuchal translucency (NT). Conventional G-banding analysis showed a de novo translocation: 45, XX, dic (9;13)(q34;p13). CMA revealed a 3.6Mb 9q34.3 microdeletion encompassing an OMIM gene of EHMT1 consistent with the diagnosis of Kleefstra syndrome and 9q subtelomeric deletion syndrome. We suggest an application of CMA at prenatal diagnosis in pregnancies with increased NT and an apparent balanced translocation on conventional karyotype.