Genomic Array CGH Research Articles

Multiple testing of local extrema for detection of change points

A new approach to detect change points based on differential smoothing and multiple testing is presented for long data sequences modeled as piecewise constant functions plus stationary ergodic Gaussian noise. As an application of the STEM algorithm for peak detection developed in Schwartzman et al. [27] and Cheng and Schwartzman [5], the method detects change points as significant local maxima and minima after smoothing and differentiating the observed sequence. The algorithm, combined with the Benjamini-Hochberg procedure for thresholding p-values, provides asymptotic strong control of the False Discovery Rate (FDR) and power consistency, as the length of the sequence and the size of the jumps get large. Simulations show that FDR levels are maintained in non-asymptotic conditions and guide the choice of smoothing bandwidth. The methods are illustrated in magnetometer sensor data and genomic array-CGH data. An R package named “dSTEM” is available in R Cran.

Genomic answers for recurrent spontaneous abortion in Saudi Arabia: An array comparative genomic hybridization approach

To study the genomics/genetic factors associated with recurrent spontaneous abortion (RSA), as ∼50% of RSA are unexplained. However, chromosome abnormalities have been reported to play major role in RSA. We performed whole genome array-CGH based genomic analysis of forty four Saudi RSA patients to identify potential molecular and chromosomal abnormalities. We identified a total of 845 alterations, usually not detected by classic cytogenetic methods, in different genomic regions using a cut off value of −0.25 and 0.25 for structural loss and gain, whereas −1.0 and 0.58 were used for single copy number deletion and duplication respectively. We identified frequent (present at least in 10% of patients) alterations including three macro-alteration at 8p23.1, 10q11.21-q11.22 and 15q11.2 as well as large numbers of micro-deletions/amplifications with affected genes including 22q11.23 (GSTT1), 3p22.2 (CTDSPL), 6p21.32 (HLA), and 8p22 (MSR1). Pathway analysis of genes located in detected CNVs regions revealed the allograft rejection signaling, IL-4 signaling, and autoimmune thyroid disease signaling as the most significant canonical pathways associated with RSA. Whole genome array CGH technique can be used to identify potential genes, biofunctions and chromosomal abnormalities associated with RSA which is supported by our findings of a number of novel CNVs/genes (22q11.23/GSTT1, 3p22.2/CTDSPL, 6p21.32/HLA, 8p22/MSR1, and 14q32.33/AKT1) and pathways in patients affected with RSA. To improve diagnosis and treatment of RSA, a comprehensive procedure is needed for identification and validation of causative genes.

Identification of an NPHP1 deletion causing adult form of nephronophthisis.

Nephronophthisis (NPHP) is an autosomal recessive cystic disease of the kidney with main characteristic features of polyuria/polydipsia, mild or absent proteinuria, interstitial fibrosis, and tubular cysts. NPHP is responsible for 5-10% of inheritable end-stage renal disease (ESRD) cases. We investigated the clinical features and genetic cause of NPHP in a Persian family with three siblings affected by tubulointerstitial nephropathy reaching ESRD in adulthood. Uromodulin (UMOD), known to be involved in adult medullary cystic kidney disease, and nephronophthisis 1 (NPHP1) were investigated in the genomic DNA of the probands using DNA sequencing, multiplex ligation-dependent probe amplification (MLPA) analysis and molecular karyotyping. No mutation was detected in UMOD. Copy number variation analysis of the NPHP1 gene using the commercially available MLPA kit identified a recurrent large homozygous deletion encompassing all NPHP1 exons. The parents were heterozygous for this deletion. Whole genome array-CGH analysis confirmed a homozygous deletion on chromosome 2q13, NPHP1 site, and revealed that the size of the copy number loss was approximately 102 Kbp. This is the first report of determination of an NPHP1 deletion size using routine diagnostic methods. The results of this study expand the knowledge about the genotype-phenotype correlations in NPHP1, and have implications for genetic counseling and family planning advice for other affected families. This is the first molecular analysis of NPHP1 in an Iranian kindred.

Genome wide analysis of novel copy number variations duplications/deletions of different epileptic patients in Saudi Arabia.

BackgroundEpilepsy is genetically complex neurological disorder affecting millions of people of different age groups varying in its type and severity. Copy number variants (CNVs) are key players in the genetic etiology of numerous neurodevelopmental disorders and prior findings also revealed that chromosomal aberrations are more susceptible against the pathogenesis of epilepsy. Novel technologies, such as array comparative genomic hybridization (array-CGH), may help to uncover the pathogenic CNVs in patients with epilepsy.ResultsThis study was carried out by high density whole genome array-CGH analysis with blood DNA samples from a cohort of 22 epilepsy patients to search for CNVs associated with epilepsy. Pathogenic rearrangements which include 6p12.1 microduplications in 5 patients covering a total region of 99.9kb and 7q32.3 microdeletions in 3 patients covering a total region of 63.9kb were detected. Two genes BMP5 and PODXL were located in the predicted duplicated and deleted regions respectively. Furthermore, these CNV findings were confirmed by qPCR.ConclusionWe have described, for the first time, several novel CNVs/genes implicated in epilepsy in the Saudi population. These findings enable us to better describe the genetic variations in epilepsy, and could provide a foundation for understanding the critical regions of the genome which might be involved in the development of epilepsy.

Selection of competent blastocysts for transfer by combining time-lapse monitoring and array CGH testing for patients undergoing preimplantation genetic screening: a prospective study with sibling oocytes.

BackgroundRecent advances in time-lapse monitoring in IVF treatment have provided new morphokinetic markers for embryonic competence. However, there is still very limited information about the relationship between morphokinetic parameters, chromosomal compositions and implantation potential. Accordingly, this study aimed at investigating the effects of selecting competent blastocysts for transfer by combining time-lapse monitoring and array CGH testing on pregnancy and implantation outcomes for patients undergoing preimplantation genetic screening (PGS).MethodsA total of 1163 metaphase II (MII) oocytes were retrieved from 138 PGS patients at a mean age of 36.6 ± 2.4 years. These sibling MII oocytes were then randomized into two groups after ICSI: 1) Group A, oocytes (n = 582) were cultured in the time-lapse system and 2) Group B, oocytes (n = 581) were cultured in the conventional incubator. For both groups, whole genomic amplification and array CGH testing were performed after trophectoderm biopsy on day 5. One to two euploid blastocysts within the most predictive morphokinetic parameters (Group A) or with the best morphological grade available (Group B) were selected for transfer to individual patients on day 6. Ongoing pregnancy and implantation rates were compared between the two groups.ResultsThere were significant differences in clinical pregnancy rates between Group A and Group B (71.1% vs. 45.9%, respectively, p = 0.037). The observed implantation rate per embryo transfer significantly increased in Group A compared to Group B (66.2% vs. 42.4%, respectively, p = 0.011). Moreover, a significant increase in ongoing pregnancy rates was also observed in Group A compared to Group B (68.9% vs. 40.5%. respectively, p = 0.019). However, there was no significant difference in miscarriage rate between the time-lapse system and the conventional incubator (3.1% vs. 11.8%, respectively, p = 0.273).ConclusionsThis is the first prospective investigation using sibling oocytes to evaluate the efficiency of selecting competent blastocysts for transfer by combining time-lapse monitoring and array CGH testing for PGS patients. Our data clearly demonstrate that the combination of these two advanced technologies to select competent blastocysts for transfer results in improved implantation and ongoing pregnancy rates for PGS patients.

Amplification of 2p as a genomic marker for transformation in lymphoma.

To outline further genetic mechanisms of transformation from follicular lymphoma (FL) to diffuse large B-cell lymphoma (DLBCL), we have performed whole genome array-CGH in 81 tumors from 60 patients [29 de novo DLBCL (dnDLBCL), 31 transformed DLBCL (tDLBCL), and 21 antecedent FL]. In 15 patients, paired tumor samples (primary FL and a subsequent tDLBCL) were available, among which three possessed more than two subsequent tumors, allowing us to follow specific genetic alterations acquired before, during, and after the transformation. Gain of 2p15–16.1 encompassing, among others, the REL, BCL11A, USP34, COMMD1, and OTX1 genes was found to be more common in the tDLBCL compared with dnDLBCL (P < 0.001). Furthermore, a high-level amplification of 2p15–16.1 was also detected in the FL stage prior to transformation, indicating its importance during the transformation event. Quantitative real-time PCR showed a higher level of amplification of REL, USP34, and COMMD1 (all involved in the NFκΒ-pathway) compared with BCL11A, which indicates that the altered genes disrupting the NFκΒ pathway may be the driver genes of transformation rather than the previously suggested BCL11A. Moreover, a 17q21.33 amplification was exclusively found in tDLBCL, never in FL (P < 0.04) or dnDLBCL, indicating an upregulation of genes of importance during the later phase of transformation. Taken together, our study demonstrates potential genomic markers for disease progression to clinically more aggressive forms. We also confirm the importance of the TP53-, CDKN2A-, and NFκΒ-pathways for the transformation from FL to DLBCL. © 2014 Wiley Periodicals, Inc.

Intragenic rearrangements in X-linked intellectual deficiency: results of a-CGH in a series of 54 patients and identification of TRPC5 and KLHL15 as potential XLID genes.

High-resolution array comparative genomic hybridization (a-CGH) enables the detection of intragenic rearrangements, such as single exon deletion or duplication. This approach can lead to the identification of new disease genes. We report on the analysis of 54 male patients presenting with intellectual deficiency (ID) and a family history suggesting X-linked (XL) inheritance or maternal skewed X-chromosome inactivation (XCI), using a home-made X-chromosome-specific microarray covering the whole human X-chromosome at high resolution. The majority of patients had whole genome array-CGH prior to the selection and we did not include large rearrangements such as MECP2 and FMR1 duplications. We identified four rearrangements considered as causative or potentially pathogenic, corresponding to a detection rate of 8%. Two CNVs affected known XLID genes and were therefore considered as causative (IL1RAPL1 and OPHN1 intragenic deletions). Two new CNVs were considered as potentially pathogenic as they affected interesting candidates for ID. The first CNV is a deletion of the first exon of the TRPC5 gene, encoding a cation channel implicated in dendrite growth and patterning, in a child presenting with ID and an autism spectrum disorder (ASD). The second CNV is a partial deletion of KLHL15, in a patient with severe ID, epilepsy, and anomalies of cortical development. In both cases, in spite of strong arguments for clinical relevance, we were not able at this stage to confirm pathogenicity of the mutations, and the causality of the variants identified in XLID remains to be confirmed.

Genomic profiling of plasma cell disorders in a clinical setting: integration of microarray and FISH, after CD138 selection of bone marrow

AimTo evaluate the role of whole genome comparative genomic hybridisation microarray (array-CGH) in detecting genomic imbalances as compared to conventional karyotype (GTG-analysis) or myeloma specific fluorescence in situ hybridisation (FISH)...

Implementation of High Resolution Whole Genome Array CGH in the Prenatal Clinical Setting: Advantages, Challenges, and Review of the Literature

Array Comparative Genomic Hybridization analysis is replacing postnatal chromosomal analysis in cases of intellectual disabilities, and it has been postulated that it might also become the first-tier test in prenatal diagnosis. In this study, array CGH was applied in 64 prenatal samples with whole genome oligonucleotide arrays (BlueGnome, Ltd.) on DNA extracted from chorionic villi, amniotic fluid, foetal blood, and skin samples. Results were confirmed with Fluorescence In Situ Hybridization or Real-Time PCR. Fifty-three cases had normal karyotype and abnormal ultrasound findings, and seven samples had balanced rearrangements, five of which also had ultrasound findings. The value of array CGH in the characterization of previously known aberrations in five samples is also presented. Seventeen out of 64 samples carried copy number alterations giving a detection rate of 26.5%. Ten of these represent benign or variables of unknown significance, giving a diagnostic capacity of the method to be 10.9%. If karyotype is performed the additional diagnostic capacity of the method is 5.1% (3/59). This study indicates the ability of array CGH to identify chromosomal abnormalities which cannot be detected during routine prenatal cytogenetic analysis, therefore increasing the overall detection rate. In addition a thorough review of the literature is presented.

Development of prognostic molecular markers in pediatric rhabdomyosarcoma based on gene expression and copy number variations.

9510 Background: Rhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma and comprises two major histological subtypes: alveolar and embryonal. The majority of alveolar tumors harbor PAX/FOXO1 fusion genes. Current patient risk stratification, unlike other pediatric embryonal tumors, does not utilize any molecular data. Therefore, we aimed to improve the risk stratification of RMS patients through the use of molecular biological data. Methods: Two independent data sets of gene expression profiling for 124 and 101 RMS were used to derive prognostic gene signatures by meta-analysis. Genomic array CGH data for 109 RMS was also evaluated to develop a prognostic marker based on copy number variations (CNVs). The performance and usefulness of these derived metagenes and CNVs as well as a previously published metagene signature were evaluated using rigorous leave-one-out cross-validation analyses. Results: The new prognostic gene expression signature, MG15, and one previously published (MG34) (Davicioni. JCO. 2010) performed well with reproducible and significant effects (HR 3.2 [1.7-5.9] p &lt; 0.001 and HR 2.5 [1.5-4.3] p &lt; 0.001, respectively). However, they did not significantly add new prognostic information over the fusion gene status (PAX3/FOXO1, PAX7/FOXO1 and Negative). Similarly, a prognostic CNV marker, although showing HR 2.9 [1.5-5.6] p &lt; 0.01, was also not improving models with fusion gene status. Within fusion negative RMS, the analysis identified prognostic markers based on either gene expression or CNVs and showed significant association with patients outcome (HR 6.3 [1.5-26.3] p ≤ 0.016 and HR 11.2 [2.5-50.7] p &lt; 0.010, respectively). Moreover, these were able to identify distinct risk groups within the COG (Children's Oncology Group) risk categories, which is currently used to guide treatment. Conclusions: Molecular signatures derived using all RMS effectively stratify patients by their risk, but most of their prognostic information is contained in the PAX/FOXO1 fusion gene status which is simpler to assay. New markers developed within the fusion negative population seem improving current RMS risk classifier and should be tested in follow-up studies.

Ring 20 syndrome mosaicism and epilepsy: a case with duplication of two BAC clones in 20q11.21-q11.22 defined by genome array-CGH

Herein, we report an unusual case of ring 20 mosaicism in a 15-year-old non-dysmorphic girl with epilepsy refractory to drug therapy. Ring 20 syndrome is a rare condition still not...

Cryptic Chromosome Rearrangements in Five Patients, with Normal and/or Abnormal Karyotypes, Associated with Mental Retardation, Autism and/or Epilepsy, Detected by BAC Genome Array-CGH

This report describes the usefulness of the BAC genome array-CGH platform in the detection of cryptic rearrangements. We examined ten patients with normal and/or abnormal karyotypes and dysmorphic features, associated with mental retardation, autism and/or epilepsy. This approach led us to discover further cryptic chromosomal rearrangements, not previously detected by conventional cytogenetic procedures, and allowed us to better delineate genotype/phenotype correlation. Our experience shows the validity of the BAC platform as a reliable method for genome-wide screening of chromosomal aberrations in patient with idiopathic mental retardation and/or in association with autism and epilepsy.

Microdeletion at 4q21.3 is associated with intellectual disability, dysmorphic facies, hypotonia, and short stature

Chromosomal imbalances are a major cause of intellectual disability (ID) and multiple congenital anomalies. We have clinically and molecularly characterized two patients with chromosome translocations and ID. Using whole genome array CGH analysis, we identified a microdeletion involving 4q21.3, unrelated to the translocations in both patients. We confirmed the 4q21.3 microdeletions using fluorescence in situ hybridization and quantitative genomic PCR. The corresponding deletion boundaries in the patients were further mapped and compared to previously reported 4q21 deletions and the associated clinical features. We determined a common region of deletion overlap that appears unique to ID, short stature, hypotonia, and dysmorphic facial features.

Aberrant Epigenetic and Genetic Marks Are Seen in Myelodysplastic Leukocytes and Reveal Dock4 as a Candidate Pathogenic Gene on Chromosome 7q

Myelodysplastic syndromes (MDS) are characterized by abnormal and dysplastic maturation of all blood lineages. Even though epigenetic alterations have been seen in MDS marrow progenitors, very little is known about the molecular alterations in dysplastic peripheral blood cells. We analyzed the methylome of MDS leukocytes by the HELP assay and determined that it was globally distinct from age-matched controls and was characterized by numerous novel, aberrant hypermethylated marks that were located mainly outside of CpG islands and preferentially affected GTPase regulators and other cancer-related pathways. Additionally, array comparative genomic hybridization revealed that novel as well as previously characterized deletions and amplifications could also be visualized in peripheral blood leukocytes, thus potentially reducing the need for bone marrow samples for future studies. Using integrative analysis, potentially pathogenic genes silenced by genetic deletions and aberrant hypermethylation in different patients were identified. DOCK4, a GTPase regulator located in the commonly deleted 7q31 region, was identified by this unbiased approach. Significant hypermethylation and reduced expression of DOCK4 in MDS bone marrow stem cells was observed in two large independent datasets, providing further validation of our findings. Finally, DOCK4 knockdown in primary marrow CD34(+) stem cells led to decreased erythroid colony formation and increased apoptosis, thus recapitulating the bone marrow failure seen in MDS. These findings reveal widespread novel epigenetic alterations in myelodysplastic leukocytes and implicate DOCK4 as a pathogenic gene located on the 7q chromosomal region.

Update on ophthalmic molecular genetics

Abstract Purpose To provide an overview of the recent technological advances in human molecular genetics that can be applied in ophthalmic genetics. Methods Since the finalization of the Human Genome Project many novel genomic technologies emerged that led to significant advances in gene identification and genetic testing of hereditary eye disorders: (1) genomewide copy number screening (array CGH); (2) genomewide SNP genotyping; (3) next‐generation sequencing. Results (1) Microarray comparative genomic hybridisation or array CGH allows genomewide discovery of submicroscopic deletions and duplications in a single experiment. This technique is applied in routine molecular cytogenetic testing. Using array CGH a causal genomic defect can be found in at least 10% of all cases with mental retardation and/or multiple congenital anomalies. In ophthalmic genetics array CGH is mainly useful in the context of developmental eye disorders, with chorioretinal coloboma and anterior segment dysgenesis as an example. (2) Genomewide chip‐based SNP genotyping can be used for homozygosity mapping in inbred and outbred pedigrees. Recent successes in gene identification using this approach are illustrated. (3) Next‐generation sequencing or NGS. The application of this technology in gene identification and genetic testing of genetically heterogeneous conditions (with LCA as a paradigm) is discussed. Conclusion The rapid progress of genomic technologies such as array CGH, SNP chip analysis and next‐generation sequencing lead to a boost in gene identification and genetic testing of both developmental and retinal eye disease.

Combined Gene Expression and Genomic Profiling Define Two Intrinsic Molecular Subtypes of Urothelial Carcinoma and Gene Signatures for Molecular Grading and Outcome

In the present investigation, we sought to refine the classification of urothelial carcinoma by combining information on gene expression, genomic, and gene mutation levels. For these purposes, we performed gene expression analysis of 144 carcinomas, and whole genome array-CGH analysis and mutation analyses of FGFR3, PIK3CA, KRAS, HRAS, NRAS, TP53, CDKN2A, and TSC1 in 103 of these cases. Hierarchical cluster analysis identified two intrinsic molecular subtypes, MS1 and MS2, which were validated and defined by the same set of genes in three independent bladder cancer data sets. The two subtypes differed with respect to gene expression and mutation profiles, as well as with the level of genomic instability. The data show that genomic instability was the most distinguishing genomic feature of MS2 tumors, and that this trait was not dependent on TP53/MDM2 alterations. By combining molecular and pathologic data, it was possible to distinguish two molecular subtypes of T(a) and T(1) tumors, respectively. In addition, we define gene signatures validated in two independent data sets that classify urothelial carcinoma into low-grade (G(1)/G(2)) and high-grade (G(3)) tumors as well as non-muscle and muscle-invasive tumors with high precisions and sensitivities, suggesting molecular grading as a relevant complement to standard pathologic grading. We also present a gene expression signature with independent prognostic effect on metastasis and disease-specific survival. We conclude that the combination of molecular and histopathologic classification systems might provide a strong improvement for bladder cancer classification and produce new insights into the development of this tumor type.

Characterization of an interstitial 4q32 deletion in a patient with mental retardation and a complex chromosome rearrangement

Interstitial deletions of chromosome band 4q32 are rare. We report on a 22-year-old female patient with a de novo interstitial deletion of chromosome 4q32 and a balanced translocation t(2;5)(p21;q12.1). Clinical problems of the patient comprised mild to moderate mental retardation, psychosis, obesity, broad nasal root, sparse lateral eyebrows, thin upper lip, short philtrum, micrognathia, and strabismus. Analysis by whole genome array CGH using an Agilent 244K oligonucleotide array and subsequent FISH using BAC clones from the 4q32 region revealed an unexpectedly complex rearrangement comprising a deletion of approximately 10 Mb in 4q32.1q32.3 and the insertion of two small fragments of 0.8 and 0.11 Mb originating from the derivative chromosome 4q32 into derivative chromosome 5q. The breakpoints of the t(2;5) translocation were mapped by BAC-FISH; no genes were disrupted by these breakpoints. The deleted interval in 4q32 harbored more than 30 genes, and haploinsufficiency of one or several of these genes is likely to have caused the clinical problems of the patient. Candidate genes for cognitive defects are GRIA2, GLRB, NPY1R, and NPY5R. In conclusion, this patient increases our knowledge about the phenotypic consequences of interstitial 4q32 deletions. Reports of patients with overlapping deletions will be needed to elucidate the role of individual genes and to establish genotype-phenotype correlations.

Mosaic deletion 11p13 in a child with dopamine beta‐hydroxylase deficiency—Case report and review of the literature

Dopamine beta-hydroxylase (DBH) deficiency is characterized by a lack of sympathetic noradrenergic function. Affected individuals exhibit profound deficits in autonomic regulation of cardiovascular function. The diagnosis of DBH deficiency is based on clinical findings, biochemical studies, and sequencing of DBH gene. We report here the characterization of a mosaic cytogenetic abnormality detected by array-CGH in a 16-year-old female with primary DBH deficiency together with dysmorphic features. These features could not be explained by DBH deficiency leading to further investigation. Karyotype was reported normal (46,XX), while a targeted genomic array-CGH revealed a mosaic loss for a segment of at least 1 Mb across 11p13. This segmental loss included the PAX6 and WT1 genes within the WAGR syndrome critical region. Interestingly, the derivative chromosome 11 was observed only in about 28% of cells analyzed. Utilizing a genome-wide oligonucleotide-based array, the deletion segment was estimated to encompass a segment of approximately 10 Mb. Mosaic deletions of 11p13 in WAGR are extremely uncommon. In this case it is distinctly possible that the patient's bilateral iris colobomata might be a manifestation, albeit abbreviated, of the haploinsufficiency for PAX6. This case highlights the importance of cytogenetic analysis when a mutation alone cannot account for the complete phenotype. It also emphasizes the enhanced ability of high-resolution array-CGH techniques in accurately detecting subtle rearrangements in a mosaic form. Finally, it demonstrates the possible phenotypic effects of low-level PAX6 haploinsufficiency in a dosage-sensitive manner.

Characterisation of hairy cell leukaemia by tiling resolution array‐based comparative Genome hybridisation: a series of 13 cases and review of the literature

Little is known about the cytogenetic features and molecular mechanisms behind hairy cell leukaemia (HCL), despite the advances in diagnosis and treatment. Therefore, we used high-resolution genome-wide array-based comparative genomic hybridisation (array-CGH) and multiplex ligation-dependent probe amplification (MLPA) to characterise copy number alterations (CNAs) in DNA from 13 cases of HCL. We also summarise CNAs and cytogenetic features in 109 HCL cases comprising our 13 cases and 96 cases from the literature. Genomic array-CGH revealed imbalances in two out of 13 cases in addition to previously described copy number variants (CNVs) found in healthy individuals. In one case, a 700 kb deletion of 20q11.22 was detected encompassing ten characterised genes, among them the TP53INP2, DNCL2A and ITCH genes. In the second case, trisomy 5, and a deletion of 5p15.2 encompassing a non-characterised gene AY328033 was found. Altogether only 20/81 (25%) of all cases studied by CGH or gene dose array revealed CNAs. The most common recurrent deletions and breakpoints were 14q22-32 (33%), 6q25 (16%), 2p12 (10%), 22q11 (10%), 17p11-13 (10%), 7q32-36 (9%), 18q11-13 (7%), 1q32-44 (6%), 8p22-23 (6%) and 7q11 (6%). Trisomy 5 occurred in 15%. In addition, several other recurrent breakpoints were identified. Although a number of genomic imbalances were identified in the HCL samples, the genome appeared remarkably stable.

Cytogenetic and array CGH characterization of de novo 1p36 duplications and deletion in a patient with congenital cataracts, hearing loss, choanal atresia, and mental retardation

We describe a 14-year-old boy with congenital bilateral cataracts, blepharophimosis, ptosis, choanal atresia, sensorineural hearing loss, short, webbed neck, poor esophageal motility, severe growth and mental retardation, skeletal anomalies, seizures, and no speech. As an infant, he had transient hypogammaglobulinemia requiring IVIG therapy. Cytogenetic studies show an apparently de novo visible duplication at 1p36.3. Fluorescence in situ hybridization (FISH) studies confirm that the common region for the 1p36 deletion syndrome (p58) is duplicated. Probes for D1Z2 at 1p36.3 and the subtelomeric region of 1p (TEL1p) are also duplicated. Array comparative genomic hybridization (aCGH) studies were done at three separate laboratories, each with somewhat different results. BAC whole genome array CGH suggests a single clone gain at the 1p terminus and a single clone deletion at 1p36.3. A targeted BAC array panel with higher resolution at the distal 1p36 region detects a telomeric duplication and an interstitial deletion. Oligonucleotide whole genomic aCGH shows the highest resolution and a more complex rearrangement: two duplications, an interstitial deletion, and a normal region. The MMP23A/B "matrix metalloproteinase 23A/B" genes are within the distal duplication region in our patient, and this patient does not have craniosynostosis. This is the first association of congenital cataracts, choanal atresia, and transient immune abnormalities with 1p36 duplication/deletion. This case illustrates the limitations of different cytogenetic technologies, and shows how three separate aCGH platforms allow for refined delineation and interpretation of the complex cytogenetic rearrangement which would not have been discovered by standard high-resolution chromosome analysis.