We used whole-genome exon-targeted oligonucleotide array comparative genomic hybridization (array CGH) in a cohort of 256 patients with developmental delay (DD)/intellectual disability (ID) with or without dysmorphic features, additional neurodevelopmental abnormalities, and/or congenital malformations. In 69 patients, we identified 84 non-polymorphic copy-number variants, among which 41 are known to be clinically relevant, including two recently described deletions, 4q21.21q21.22 and 17q24.2. Chromosomal microarray analysis revealed also 15 potentially pathogenic changes, including three rare deletions, 5q35.3, 10q21.3, and 13q12.11. Additionally, we found 28 copy-number variants of unknown clinical significance. Our results further support the notion that copy-number variants significantly contribute to the genetic etiology of DD/ID and emphasize the efficacy of the detection of novel candidate genes for neurodevelopmental disorders by whole-genome array CGH.Electronic supplementary materialThe online version of this article (doi:10.1007/s13353-013-0181-x) contains supplementary material, which is available to authorized users.

Clinical manifestations of Jacobsen syndrome (JBS) depend on the size of the 11qter deletion, which usually varies between approximately 7 and 20 Mb. Typical JBS features include developmental delay/mental retardation, short stature, congenital heart defects, thrombocytopenia, and characteristic dysmorphic facial features. We report on a family in which a 4-year-old girl as well as her mother and maternal uncle present with subtle features of JBS. Notably, neither thrombocytopenia nor congenital anomalies were detected in this family. Cytogenetic analyses revealed normal karyotypes. Using fluorescence in situ hybridization (FISH) and whole-genome oligonucleotide array CGH analyses, we identified an approximately 5 Mb deletion of the terminal part of chromosome 11q in all the three affected family members. The deletion breakpoint was mapped between 129,511,419 and 129,519,794 bp. This is the smallest deletion reported in a JBS patient. Interestingly, the FLI1 (friend leukemia virus integration 1) hematopoiesis factor gene located approximately 6.5 Mb from 11qter and usually deleted in patients with JBS, is intact. Our data support previous hypotheses that FLI1 haploinsufficiency is responsible for thrombocytopenia in patients with JBS.

Neurodevelopmental disorders have long been associated with chromosomal abnormalities, including microdeletions and microduplications. Submicroscopic 14q11.2 deletions involving the CHD8 and SUPT16H genes have been reported in patients with developmental delay (DD)/intellectual disability (ID) or autism spectrum disorders (ASDs) and/or macrocephaly. Recently, disruptive CHD8 mutations were described in patients with similar phenotypes further showing pivotal role of CHD8 gene in the pathogenesis of DD/ID or ASDs. We report here the first case of ~445 kb de novo microduplication, encompassing the minimal critical 14q11.2 deletion region, in 8-year-old boy showing DD, cognitive impairment and facial dysmorphism. Our results suggest that gain of the chromosomal region 14q11.2 is causative for clinical findings present in the patient.

BackgroundDuplication of the distal part of chromosome 6p is a rare genetic syndrome. Renal involvement has been reported in the majority of patients, including a wide range of congenital abnormalities of kidney and urinary tract and, occasionally, a proteinuric glomerulopathy.Case presentationHere, we report a 13-year-old girl with 6p25.3p22.1 duplication who presented with proteinuria in infancy, was later diagnosed as focal segmental glomerulosclerosis, progressed to end-stage renal disease and was successfully transplanted.ConclusionA systematic literature review suggests that 15–20 % of individuals with distal 6p duplication develop progressive proteinuric glomerulopathy. Monitoring of kidney function should be recommended in all cases.Electronic supplementary materialThe online version of this article (doi:10.1186/s12882-016-0246-2) contains supplementary material, which is available to authorized users.

The aim of this study was to determine the suitability of the comparative genomic hybridization to microarray (aCGH) technique for prenatal diagnosis, but also to assess the frequency of chromosomal aberrations that may lead to fetal malformations but are not included in the diagnostic report. We present the results of the aCGH in a cohort of 7400 prenatal cases, indicated for invasive testing due to ultrasound abnormalities, high-risk for serum screening, thickened nuchal translucency, family history of genetic abnormalities or congenital abnormalities, and advanced maternal age (AMA). The overall chromosomal aberration detection rate was 27.2% (2010/7400), including 71.2% (1431/2010) of numerical aberrations and 28.8% (579/2010) of structural aberrations. Additionally, the detection rate of clinically significant copy number variants (CNVs) was 6.8% (505/7400) and 0.7% (57/7400) for variants of unknown clinical significance. The detection rate of clinically significant submicroscopic CNVs was 7.9% (334/4204) for fetuses with structural anomalies, 5.4% (18/336) in AMA, 3.1% (22/713) in the group of abnormal serum screening and 6.1% (131/2147) in other indications. Using the aCGH method, it was possible to assess the frequency of pathogenic chromosomal aberrations, of likely pathogenic and of uncertain clinical significance, in the groups of cases with different indications for an invasive test.