Deletion of the distal long arm of chromosome 10; is there a characteristic phenotype? A report of 15 de novo and familial cases

Heterozygous loss-of-function SMC3 variants are associated with variable growth and developmental features

Heterozygous missense variants and in-frame indels in SMC3 are a cause of Cornelia de Lange syndrome (CdLS), marked by intellectual disability, growth deficiency, and dysmorphism, via an apparent dominant-negative mechanism. However, the spectrum of manifestations associated with SMC3 loss-of-function variants has not been reported, leading to hypotheses of alternative phenotypes or even developmental lethality. We used matchmaking servers, patient registries, and other resources to identify individuals with heterozygous, predicted loss-of-function (pLoF) variants in SMC3, and analyzed population databases to characterize mutational intolerance in this gene. Here, we show that SMC3 behaves as an archetypal haploinsufficient gene: it is highly constrained against pLoF variants, strongly depleted for missense variants, and pLoF variants are associated with a range of developmental phenotypes. Among 14 individuals with SMC3 pLoF variants, phenotypes were variable but coalesced on low growth parameters, developmental delay/intellectual disability, and dysmorphism, reminiscent of atypical CdLS. Comparisons to individuals with SMC3 missense/in-frame indel variants demonstrated an overall milder presentation in pLoF carriers. Furthermore, several individuals harboring pLoF variants in SMC3 were nonpenetrant for growth, developmental, and/or dysmorphic features, and some had alternative symptomatologies with rational biological links to SMC3. Analyses of tumor and model system transcriptomic data and epigenetic data in a subset of cases suggest that SMC3 pLoF variants reduce SMC3 expression but do not strongly support clustering with functional genomic signatures of typical CdLS. Our finding of substantial population-scale LoF intolerance in concert with variable growth and developmental features in subjects with SMC3 pLoF variants expands the scope of cohesinopathies, informs on their allelic architecture, and suggests the existence of additional clearly LoF-constrained genes whose disease links will be confirmed only by multilayered genomic data paired with careful phenotyping.

Heterozygous loss-of-function SMC3 variants are associated with variable and incompletely penetrant growth and developmental features

Heterozygous missense variants and in-frame indels in SMC3 are a cause of Cornelia de Lange syndrome (CdLS), marked by intellectual disability, growth deficiency, and dysmorphism, via an apparent dominant-negative mechanism. However, the spectrum of manifestations associated with SMC3 loss-of-function variants has not been reported, leading to hypotheses of alternative phenotypes or even developmental lethality. We used matchmaking servers, patient registries, and other resources to identify individuals with heterozygous, predicted loss-of-function (pLoF) variants in SMC3, and analyzed population databases to characterize mutational intolerance in this gene. Here, we show that SMC3 behaves as an archetypal haploinsufficient gene: it is highly constrained against pLoF variants, strongly depleted for missense variants, and pLoF variants are associated with a range of developmental phenotypes. Among 13 individuals with SMC3 pLoF variants, phenotypes were variable but coalesced on low growth parameters, developmental delay/intellectual disability, and dysmorphism reminiscent of atypical CdLS. Comparisons to individuals with SMC3 missense/in-frame indel variants demonstrated a milder presentation in pLoF carriers. Furthermore, several individuals harboring pLoF variants in SMC3 were nonpenetrant for growth, developmental, and/or dysmorphic features, some instead having intriguing symptomatologies with rational biological links to SMC3 including bone marrow failure, acute myeloid leukemia, and Coats retinal vasculopathy. Analyses of transcriptomic and epigenetic data suggest that SMC3 pLoF variants reduce SMC3 expression but do not result in a blood DNA methylation signature clustering with that of CdLS, and that the global transcriptional signature of SMC3 loss is model-dependent. Our finding of substantial population-scale LoF intolerance in concert with variable penetrance in subjects with SMC3 pLoF variants expands the scope of cohesinopathies, informs on their allelic architecture, and suggests the existence of additional clearly LoF-constrained genes whose disease links will be confirmed only by multi-layered genomic data paired with careful phenotyping.

Cytogenomic Investigation of Syndromic Brazilian Patients with Differences of Sexual Development

BACKGROUND

Cytogenomic methods have gained space in the clinical investigation of patients with disorders/differences in sexual development (DSD). Here we evaluated the role of the SNP array in achieving a molecular diagnosis in Brazilian patients with syndromic DSD of unknown etiology.

METHODS

Twenty-two patients with DSD and syndromic features were included in the study and underwent SNP-array analysis.

RESULTS

In two patients, the diagnosis of 46,XX SRY + DSD was established. Additionally, two deletions were revealed (3q29 and Xp22.33), justifying the syndromic phenotype in these patients. Two pathogenic CNVs, a 10q25.3-q26.2 and a 13q33.1 deletion encompassing the FGFR2 and the EFNB2 gene, were associated with genital atypia and syndromic characteristics in two patients with 46,XY DSD. In a third 46,XY DSD patient, we identified a duplication in the 14q11.2-q12 region of 6.5 Mb associated with a deletion in the 21p11.2-q21.3 region of 12.7 Mb. In a 46,XY DSD patient with delayed neuropsychomotor development and congenital cataracts, a 12 Kb deletion on chromosome 10 was found, partially clarifying the syndromic phenotype, but not the genital atypia.

CONCLUSIONS

The SNP array is a useful tool for DSD patients, identifying the molecular etiology in 40% (2/5) of patients with 46,XX DSD and 17.6% (3/17) of patients with 46,XY DSD.

CTBP1 and CTBP2 mutations underpinning neurological disorders: a systematic review

C-terminal binding proteins (CtBP1/2) are transcriptional coregulators that play a significant role during vertebrate neurodevelopment. This systematic review aims to identify case reports with genetic variants in CTBP1 and CTBP2 associated with brain development syndromes.

We screened different databases (PubMed, Scopus, Google Scholar, LILACS) by systematically searching journals and checking reference lists and citations of background papers. We found fourteen cases (10 males) from five papers carrying two pathogenic, heterozygous variants in the CTBP1 gene (13 individuals carried the missense mutation c.991C T, p.Arg342Trp, and one subject carrying the 2-base pair deletion c.1315_1316delCA, p.Gln439ValfsTer84). These mutations were de novo in 13 cases and one case of maternal germinal mosaicism. Two variants are in the same domain of the protein: Pro-Leu-Asp-Leu-Ser (PLDLS) C terminal. Patients with these mutations exhibit a phenotype with intellectual disability, HADDTS syndrome (hypotonia, ataxia, developmental delay, and tooth enamel defects), and cerebellar volume loss. We did not identify reported cases associated with homozygous mutations harbored in CTBP1. We did not identify any report of neurodevelopment phenotypes associated with heterozygous or homozygous CTBP2 mutations. Due to CTBP2/RIBEYE being a gene with dual function, identifying and interpreting the potential pathogenic variants is challenging.

Further, homozygous mutations in the CTBP2 gene may be lethal. The mechanisms involved in the pathogenesis of neurodevelopment due to variants of these proteins have not yet been elucidated, despite some functional evidence. Further studies should be conducted to understand these transcription factors and their interaction with each other and their partners.

Investigation of Genetic Causes in Patients with Congenital Heart Disease in Qatar: Findings from the Sidra Cardiac Registry

Congenital heart disease (CHD) is one of the most common forms of birth defects worldwide, with a prevalence of 1–2% in newborns. CHD is a multifactorial disease partially caused by genetic defects, including chromosomal abnormalities and single gene mutations. Here, we describe the Sidra Cardiac Registry, which includes 52 families and a total of 178 individuals, and investigate the genetic etiology of CHD in Qatar. We reviewed the results of genetic tests conducted in patients as part of their clinical evaluation, including chromosomal testing. We also performed whole exome sequencing (WES) to identify potential causative variants. Sixteen patients with CHD had chromosomal abnormalities that explained their complex CHD phenotype, including six patients with trisomy 21. Moreover, using exome analysis, we identified potential CHD variants in 24 patients, revealing 65 potential variants in 56 genes. Four variants were classified as pathogenic/likely pathogenic based on the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) classification; these variants were detected in four patients. This study sheds light on several potential genetic variants contributing to the development of CHD. Additional functional studies are needed to better understand the role of the identified variants in the pathogenesis of CHD.

An Integrated Phenotypic and Genotypic Approach Reveals a High-Risk Subtype Association for EBF3 Missense Variants Affecting the Zinc Finger Domain

OBJECTIVE

Collier/Olf/EBF (COE) transcription factors have distinct expression patterns in the developing and mature nervous system. To date, a neurological disease association has been conclusively established for only the Early B-cell Factor-3 (EBF3) COE family member through the identification of heterozygous loss-of-function variants in individuals with autism spectrum/neurodevelopmental disorders (NDD). Here, we identify a symptom severity risk association with missense variants primarily disrupting the zinc finger domain (ZNF) in EBF3-related NDD.

METHODS

A phenotypic assessment of 41 individuals was combined with a literature meta-analysis for a total of 83 individuals diagnosed with EBF3-related NDD. Quantitative diagnostic phenotypic and symptom severity scales were developed to compare EBF3 variant type and location to identify genotype-phenotype correlations. To stratify the effects of EBF3 variants disrupting either the DNA-binding domain (DBD) or the ZNF, we used in vivo fruit fly UAS-GAL4 expression and in vitro luciferase assays.

RESULTS

We show that patient symptom severity correlates with EBF3 missense variants perturbing the ZNF, which is a key protein domain required for stabilizing the interaction between EBF3 and the target DNA sequence. We found that ZNF-associated variants failed to restore viability in the fruit fly and impaired transcriptional activation. However, the recurrent variant EBF3 p.Arg209Trp in the DBD is capable of partially rescuing viability in the fly and preserved transcriptional activation.

INTERPRETATION

We describe a symptom severity risk association with ZNF perturbations and EBF3 loss-of-function in the largest reported cohort to date of EBF3-related NDD patients. This analysis should have potential predictive clinical value for newly identified patients with EBF3 gene variants. ANN NEUROL 2022;92:138-153.

A Case of Inherited t(4;10)(q26;q26.2) Chromosomal Translocation Elucidated by Multiple Chromosomal and Molecular Analyses. Case Report and Review of the Literature

We present a complex chromosomal anomaly identified using cytogenetic and molecular methods. The child was diagnosed during the neonatal period with a multiple congenital anomalies syndrome characterized by: flattened occipital region; slight turricephaly; tall and broad forehead; hypertelorism; deep-set eyes; down slanting and short palpebral fissures; epicanthic folds; prominent nose with wide root and bulbous tip; microstomia; micro-retrognathia, large, short philtrum with prominent reliefs; low set, prominent ears; and congenital heart disease. The GTG banding karyotype showed a 46,XY,der(10)(10pter→10q26.2::4q26→4qter) chromosomal formula and his mother presented an apparently balanced reciprocal translocation: 46,XX,t(4;10)(q26;q26.2). The chromosomal anomalies of the child were confirmed by MLPA, and supplementary investigation discovered a quadruplication of the 4q35.2 region. The mother has a triplication of the same chromosomal fragment (4q35.2). Using array-CGH, we described the anomalies completely. Thus, the boy has a 71,057 kb triplication of the 4q26-q35.2 region, a 562 kb microdeletion in the 10q26.3 region, and a 795 kb quadruplication of the 4q35.2 region, while the mother presents a 795 kb triplication of the 4q35.2 region. Analyzing these data, we consider that the boy's phenotype is influenced only by the 4q partial trisomy. We compare our case with similar cases, and we review the literature data.

Further refining the critical region of 10q26 microdeletion syndrome: A possible involvement of INSYN2 and NPS in the cognitive phenotype

BACKGROUND

The 10q26 subtelomeric microdeletion syndrome is a rare and clinically heterogeneous disorder. The precise relationships between the causative genes and the phenotype are unclear.

CASE PRESENTATION

We report two new cases of 860 kb deletion of 10q26.2 identified by array CGH in a fetus with intrauterine growth retardation and his mother. The deleted region encompassed only four coding genes, DOCK1, INSYN2, NPS and FOX12. The proband had dysmorphic facies characterized by a high forehead, malformed ears, a prominent nose, and retrognathia. He had bilateral club feet, clinodactily and mild psychomotor retardation. His mother had a short stature, microcephaly, a long face with a high forehead and bitemporal narrowing, arched and sparse eyebrows, strabismus, prominent nose and chin, a thin upper lip and large protruding ears, and mild intellectual disability.

CONCLUSIONS

This study presents the smallest 10q26.2 deletion so far identified, which further refines the minimal critical region associated with the 10q26 microdeletion syndrome. It focuses on three genes potentially responsible for the phenotype: DOCK1, which is the major candidate gene, and INSYN2 and NPS, which could be involved in cognitive functions.

Clinical delineation of an adult female patient with a rare interstitial 10q24.32q25.1 microdeletion

Interstitial deletions encompassing the 10q24.32q25.1 region are rare. Only three patients have been reported in literature to date. We describe a 44-year-old female with a 2.8 Mb microdeletion in 10q24.32q25.1. Clinical findings in this patient are delineated and compared to previously reported patients with (partly) overlapping microdeletions. Based on the few descriptions available in the literature, the major phenotypic features of microdeletion 10q24.32q25.1 seem to be profound developmental delay, severe intellectual disability, short stature, cleft lip and palate, multiple congenital malformations (brain, kidney and cardiac), ophthalmic problems and an increased risk to develop basal cell carcinoma. As far as we are aware, this is the first report of an adult patient with a 10q24.32q25.1 microdeletion in literature. Suggestions are made regarding the medical work-up for newly identified patients with a 10q24.32q25.1 microdeletion as well as for a possible interaction of the compound deletion of SUFU and FGF8 in midline craniofacial abnormalities.

Intellectual disability: dendritic anomalies and emerging genetic perspectives

Intellectual disability (ID) corresponds to several neurodevelopmental disorders of heterogeneous origin in which cognitive deficits are commonly associated with abnormalities of dendrites and dendritic spines. These histological changes in the brain serve as a proxy for underlying deficits in neuronal network connectivity, mostly a result of genetic factors. Historically, chromosomal abnormalities have been reported by conventional karyotyping, targeted fluorescence in situ hybridization (FISH), and chromosomal microarray analysis. More recently, cytogenomic mapping, whole-exome sequencing, and bioinformatic mining have led to the identification of novel candidate genes, including genes involved in neuritogenesis, dendrite maintenance, and synaptic plasticity. Greater understanding of the roles of these putative ID genes and their functional interactions might boost investigations into determining the plausible link between cellular and behavioral alterations as well as the mechanisms contributing to the cognitive impairment observed in ID. Genetic data combined with histological abnormalities, clinical presentation, and transgenic animal models provide support for the primacy of dysregulation in dendrite structure and function as the basis for the cognitive deficits observed in ID. In this review, we highlight the importance of dendrite pathophysiology in the etiologies of four prototypical ID syndromes, namely Down Syndrome (DS), Rett Syndrome (RTT), Digeorge Syndrome (DGS) and Fragile X Syndrome (FXS). Clinical characteristics of ID have also been reported in individuals with deletions in the long arm of chromosome 10 (the q26.2/q26.3), a region containing the gene for the collapsin response mediator protein 3 (CRMP3), also known as dihydropyrimidinase-related protein-4 (DRP-4, DPYSL4), which is involved in dendritogenesis. Following a discussion of clinical and genetic findings in these syndromes and their preclinical animal models, we lionize CRMP3/DPYSL4 as a novel candidate gene for ID that may be ripe for therapeutic intervention.

Prenatal diagnosis of concomitant distal 5q duplication and terminal 10q deletion in a fetus with intrauterine growth restriction, congenital diaphragmatic hernia and congenital heart defects

OBJECTIVE

We present prenatal diagnosis of concomitant distal 5q duplication and terminal 10q deletion in a fetus with intrauterine growth restriction (IUGR), congenital diaphragmatic hernia (CDH) and congenital heart defects (CHD).

CASE REPORT

A 34-year-old, gravida 4, para 2, woman was referred for amniocentesis at 21 weeks of gestation because of advanced maternal age and IUGR. There was no congenital malformation in the family. Amniocentesis revealed a derivative chromosome 10 with an additional maternal on the terminal region of 10q. Array comparative genomic hybridization (aCGH) analysis on the DNA extracted from the cultured amniocytes revealed a result of arr 5q31.3q35.5 (142, 548, 354-180,696,806) × 3.0, arr 10q26.3 (132, 932, 808-135,434,178) × 1.0 [GRCh37 (hg19)] with a 2.50-Mb deletion of 10q26.3 encompassing 19 [Online Mendelian Inheritance in Man (OMIM)] genes and a 38.15-Mb duplication of 5q31.3-q35.5 encompassing 195 OMIM genes including four CDH candidate genes of NDST1, ADAM19, NSD1 and MAML1. The mother was found to have a karyotype of 46,XX,t(5; 10) (q31.3; q26.3). Therefore, the fetal karyotype was 46,XX,der(10)t(5; 10)(q31.3; q26.3)mat. Prenatal ultrasound showed IUGR, right CDH, transposition of great artery, double outlet of right ventricle and right atrial isomerism. The pregnancy was terminated, and a malformed fetus was delivered with facial dysmorphism.

CONCLUSION

Fetuses with concomitant distal 5q duplication and terminal 10q deletion may present IUGR, CDH and CHD on prenatal ultrasound.

Molecular Mechanisms of Syndromic Cryptorchidism: Data Synthesis of 50 Studies and Visualization of Gene-Disease Network

Background: Cryptorchidism is one of the most frequent congenital birth defects in male children and is present in 2-4% of full-term male births. It has several possible health effects including reduced fertility, increased risk for testicular neoplasia, testicular torsion, and psychological consequences. Cryptorchidism is often diagnosed as comorbid; copresent with other diseases. It is also present in clinical picture of several syndromes. However, this field has not been systematically studied. The aim of the present study was to catalog published cases of syndromes which include cryptorchidism in the clinical picture and associated genomic information. Methods: The literature was extracted from Public/Publisher MEDLINE and Web of Science databases, using the keywords including: syndrome, cryptorchidism, undescended testes, loci, and gene. The obtained data was organized in a table according to the previously proposed standardized data format. The results of the study were visually represented using Gephi and karyotype view. Results: Fifty publications had sufficient data for analysis. Literature analysis resulted in 60 genomic loci, associated with 44 syndromes that have cryptorchidism in clinical picture. Genomic loci included 38 protein-coding genes and 22 structural variations containing microdeletions and microduplications. Loci, associated with syndromic cryptorchidism are located on 16 chromosomes. Visualization of retrieved data is presented in a gene-disease network. Conclusions: The study is ongoing and further studies will be needed to develop a complete catalog with the data from upcoming publications. Additional studies will also be needed for revealing of molecular mechanisms associated with syndromic cryptorchidism and revealing complete diseasome network.

Genome-wide screening for smallest regions of overlaps in cryptorchidism

Cryptorchidism is a urogenital abnormality associated with increased rates of testicular neoplasia and impaired spermatogenesis. The field is facing expansion of genomics data; however, it lacks protocols for biomarker prioritization. Identification of smallest regions of overlap (SRO) presents an approach for candidate gene identification but has not yet been systematically conducted in cryptorchidism. The aim of this study was to conduct a genome-wide screening for SRO (GW-SRO) associated with cryptorchidism development. We updated the Cryptorchidism Gene Database to version 3, remapped genomic coordinates of loci from older assemblies to the GRCh38 and performed genome-wide screening for overlapping regions associated with cryptorchidism risk. A total of 73 chromosomal loci (68 involved in chromosomal mutations and five copy number variations) described in 37 studies associated with cryptorchidism risk in humans were used for SRO identification. Analysis resulted in 18 SRO, based on deletions, duplications, inversions, derivations and copy number variations. Screening for SRO was challenging owing to heterogeneous reporting of genomic locations. To our knowledge, this is the first GW-SRO study for cryptorchidism and it presents the basis for further narrowing of critical regions for cryptorchidism and planning functional experiments. The developed protocol could also be applied to other multifactorial diseases.

Expansion of the clinical phenotype of the distal 10q26.3 deletion syndrome to include ataxia and hyperemia of the hands and feet

Distal deletion of the long arm of chromosome 10 is associated with a dysmorphic craniofacial appearance, microcephaly, behavioral issues, developmental delay, intellectual disability, and ocular, urogenital, and limb abnormalities. Herein, we present clinical, molecular, and cytogenetic investigations of four patients, including two siblings, with nearly identical terminal deletions of 10q26.3, all of whom have an atypical presentation of this syndrome. Their prominent features include ataxia, mild-to-moderate intellectual disability, and hyperemia of the hands and feet, and they do not display many of the other features commonly associated with deletions of this region. These results point to a novel gene locus associated with ataxia and highlight the variability of the clinical presentation of patients with deletions of this region.

Chromosome 10q26 deletion syndrome: Two new cases and a review of the literature

The current study presents the cases of two unrelated patients with similar clinical features, including craniofacial anomalies, developmental delay/intellectual disability and cardiac malformations, that are consistent with chromosome 10q26 deletion syndrome. High‑resolution single‑nucleotide polymorphism analysis revealed that 10q26 terminal deletions were present in these two patients. The locations and sizes of the 10q26 deletions in these two patients were compared with the locations and sizes of 10q26 deletions in 30 patients recorded in the DECIPHER database and 18 patients characterized in previous studies through chromosomal microarray analysis. The clinical features and locations of the 10q26 deletions of these patients were reviewed in an attempt to map or refine a critical region (CR) for phenotypes. Additionally, the association between previously suggested CRs and phenotypic variability was discussed. The current study emphasize that a distal 10q26 terminal deletion with a breakpoint at ~130 Mb may contribute to the common clinical features of 10q26 deletion syndrome.

A de novo microdeletion in a patient with inner ear abnormalities suggests that the 10q26.13 region contains the responsible gene

Microdeletions in the 10q26.1 region are related to intellectual disability, growth delay, microcephaly, distinctive craniofacial features, cardiac defects, genital abnormalities and inner ear abnormalities. The genes responsible for inner ear abnormalities have been narrowed to fibroblast growth factor receptor 2 gene (FGFR2), H6 family homeobox 2 gene (HMX2) and H6 family homeobox 3 gene (HMX3). An additional patient with distinctive craniofacial features, congenital deafness and balance dysfunctions showed a de novo microdeletion of 10q26.11q26.13, indicating the existence of a gene responsible for inner ear abnormalities in this region.

Hearing loss, coloboma and left ventricular enlargement in a boy with an interstitial 10q26 deletion

Distal deletion of the long arm of chromosome 10 with breakpoints mapped at 10q26 is a well-recognized contiguous genomic disorder. A wide spectrum of clinical findings is seen in affected individuals and the common clinical features include craniofacial dysmorphia, developmental delay, intellectual disability, hypotonia, cardiovascular defects, and urogenital malformations. We report herein on a male patient with a 5.5 Mb interstitial deletion of 10q26.11q2613 and compare his clinical presentation to previously reported cases. Apart from characteristic phenotypes seen in 10q26 deletion syndrome, he presents with colobomas and left ventricle enlargement. These are cardiovascular and ophthalmological findings that have not been described in prior cases. © 2016 Wiley Periodicals, Inc.

Molecular and clinical analyses with neuropsychological assessment of a case of del(10)(q26.2qter) without intellectual disability: Genomic and transcriptomic combined approach and review of the literature

Terminal deletion of the long arm of the chromosome 10 is a rare but well known abnormality, with a large phenotypic variability. Very few data are available about subtelomeric deletion 10q26 patients without intellectual disability. Herein, we report the case of a young adult with a classical 10q26.2qter deletion. She exhibited mainly short stature at birth and in childhood/adulthood without intellectual disability or behavioral problems. After clinical and neuropsychological assessments, we performed genomic array and transcriptomic analysis and compared our results to the data available in the literature. The patient presents a 6.525 Mb heterozygous 10q26.2qter deletion, encompassed 48 genes. Among those genes, DOCK1, C10orf90, and CALY previously described as potential candidate genes for intellectual disability, were partially or completed deleted. Interestingly, they were not deregulated as demonstrated by transcriptomic analysis. This allowed us to suggest that the mechanism involved in the deletion 10qter phenotype is much more complex that only the haploinsufficiency of DOCK1 or other genes encompassed in the deletion. Genomic and transcriptomic combined approach has to be considered to understand this pathogenesis. © 2016 Wiley Periodicals, Inc.

Persistence of müllerian duct structures in a genetic male with distal monosomy 10q

Persistent müllerian duct syndrome (PMD) with antimüllerian hormone (AMH) deficiency is usually associated with mutations or deletions of the AMH gene, although many cases have no identified gene association. We report on a genetic male with PMD and AMH deficiency associated with distal monosomy 10q. A term 3,230 g infant was born to a healthy 27-year-old. Fetal ultrasound had shown possible genital ambiguity. Postnatal exam showed a 0.5 cm phallus with basal meatus, normal scrotum with no palpable gonads, no vaginal orifice, and a rectal fistula with an imperforate anus. Voiding cystourethrogram with ultrasound, cystoscopy, and laparoscopy showed normal bladder, urethral orifice, distal vagina, cervix, and bilateral abdominal testis. At 24 hours of life, testosterone was within normal range with low AMH level. Chromosome microarray analysis showed 46, XY, del10(10q25.3q26.13) involving an 8.2 MB interstitial deletion. Whole exome sequencing identified a NOTCH2 variant (1p11.2). AMH sequencing revealed no abnormalities. Following multidisciplinary team and parent discussion, male gender was assigned. Testosterone treatment resulted in penile length of 1.5 cm. Bilateral orchiopexy and posterior sagittal anorectoplasty were performed at 11 months of age; rudimentary müllerian structures were identified. This observation suggests an association of 10qter elements with male differentiation including AMH expression and is similar to a patient with 46, XY, del(10q26.1) in which AMH levels were not reported. Regional candidate genes include FGFR2 (10q26.13). The possible contribution of a NOTCH2 variant cannot be excluded.

Mild Phenotype in a Patient with a De Novo 6.3 Mb Distal Deletion at 10q26.2q26.3

We report on a 29-year-old Greek-Cypriot female with a de novo 6.3 Mb distal 10q26.2q26.3 deletion. She had a very mild neurocognitive phenotype with near normal development and intellect. In addition, she had certain distinctive features and postural orthostatic tachycardia. We review the relevant literature and postulate that certain of her features can be diagnostically relevant. This report illustrates the powerful diagnostic ability of array-CGH in the elucidation of relatively mild phenotypes.

Contribution of copy number variants (CNVs) to congenital, unexplained intellectual and developmental disabilities in Lebanese patients

Background

Chromosomal microarray analysis (CMA) is currently the most widely adopted clinical test for patients with unexplained intellectual disability (ID), developmental delay (DD), and congenital anomalies. Its use has revealed the capacity to detect copy number variants (CNVs), as well as regions of homozygosity, that, based on their distribution on chromosomes, indicate uniparental disomy or parental consanguinity that is suggestive of an increased probability of recessive disease.

Results

We screened 149 Lebanese probands with ID/DD and 99 healthy controls using the Affymetrix Cyto 2.7 M and SNP6.0 arrays. We report all identified CNVs, which we divided into groups.

Pathogenic CNVs were identified in 12.1% of the patients. We review the genotype/phenotype correlation in a patient with a 1q44 microdeletion and refine the minimal critical regions responsible for the 10q26 and 16q monosomy syndromes.

Several likely causative CNVs were also detected, including new homozygous microdeletions (9p23p24.1, 10q25.2, and 8p23.1) in 3 patients born to consanguineous parents, involving potential candidate genes.

However, the clinical interpretation of several other CNVs remains uncertain, including a microdeletion affecting ATRNL1. This CNV of unknown significance was inherited from the patient’s unaffected-mother; therefore, additional ethnically matched controls must be screened to obtain enough evidence for classification of this CNV.

Conclusion

This study has provided supporting evidence that whole-genome analysis is a powerful method for uncovering chromosomal imbalances, regardless of consanguinity in the parents of patients and despite the challenge presented by analyzing some CNVs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13039-015-0130-y) contains supplementary material, which is available to authorized users.

Clinical comparison of 10q26 overlapping deletions: delineating the critical region for urogenital anomalies

The 10q26 deletion syndrome is a clinically heterogeneous disorder. The most common phenotypic characteristics include pre- and/or postnatal growth retardation, microcephaly, developmental delay/intellectual disability and a facial appearance consisting of a broad nasal bridge with a prominent nose, low-set malformed ears, strabismus, and a thin vermilion of the upper lip. In addition, limb and cardiac anomalies as well as urogenital anomalies are occasionally observed. In this report, we describe three unrelated females with 10q26 terminal deletions who shared clinical features of the syndrome, including urogenital defects. Cytogenetic studies showed an apparently de novo isolated deletion of the long arm of chromosome 10, with breakpoints in 10q26.1, and subsequent oligo array-CGH analysis confirmed the terminal location and defined the size of the overlapping deletions as ∼ 13.46, ∼ 9.31 and ∼ 9.17 Mb. We compared the phenotypic characteristics of the present patients with others reported to have isolated deletions and we suggest that small 10q26.2 terminal deletions may be associated with growth retardation, developmental delay/intellectual disability, craniofacial features and external genital anomalies whereas longer terminal deletions affecting the 10q26.12 and/or 10q26.13 regions may be responsible for renal/urinary tract anomalies. We propose that the haploinsufficiency of one or several genes located in the 10q26.12-q26.13 region may contribute to the renal or urinary tract pathogenesis and we highlight the importance of FGFR2 and probably of CTBP2 as candidate genes.

Prenatal diagnosis of trisomy 6q25.3-qter and monosomy 10q26.12-qter by array CGH in a fetus with an apparently normal karyotype

We present the prenatal case of a 12.5-Mb duplication involving 6q25-qter and a 12.2-Mb deletion encompassing 10q26-qter diagnosed by aCGH, while conventional karyotype showed normal results. The genotype–phenotype correlation between individual microarray and clinical findings adds to the emerging atlas of chromosomal abnormalities associated with specific prenatal ultrasound abnormalities.

DSDs: genetics, underlying pathologies and psychosexual differentiation

Mammalian sex determination is the unique process whereby a single organ, the bipotential gonad, undergoes a developmental switch that promotes its differentiation into either a testis or an ovary. Disruptions of this complex genetic process during human development can manifest as disorders of sex development (DSDs). Sex development can be divided into two distinct processes: sex determination, in which the bipotential gonads form either testes or ovaries, and sex differentiation, in which the fully formed testes or ovaries secrete local and hormonal factors to drive differentiation of internal and external genitals, as well as extragonadal tissues such as the brain. DSDs can arise from a number of genetic lesions, which manifest as a spectrum of gonadal (gonadal dysgenesis to ovotestis) and genital (mild hypospadias or clitoromegaly to ambiguous genitalia) phenotypes. The physical attributes and medical implications associated with DSDs confront families of affected newborns with decisions, such as gender of rearing or genital surgery, and additional concerns, such as uncertainty over the child's psychosexual development and personal wishes later in life. In this Review, we discuss the underlying genetics of human sex determination and focus on emerging data, genetic classification of DSDs and other considerations that surround gender development and identity in individuals with DSDs.

Genetics of bipolar disorder

Bipolar disorder is a common, complex genetic disorder, but the mode of transmission remains to be discovered. Many researchers assume that common genomic variants carry some risk for manifesting the disease. The research community has celebrated the first genome-wide significant associations between common single nucleotide polymorphisms (SNPs) and bipolar disorder. Currently, attempts are under way to translate these findings into clinical practice, genetic counseling, and predictive testing. However, some experts remain cautious. After all, common variants explain only a very small percentage of the genetic risk, and functional consequences of the discovered SNPs are inconclusive. Furthermore, the associated SNPs are not disease specific, and the majority of individuals with a "risk" allele are healthy. On the other hand, population-based genome-wide studies in psychiatric disorders have rediscovered rare structural variants and mutations in genes, which were previously known to cause genetic syndromes and monogenic Mendelian disorders. In many Mendelian syndromes, psychiatric symptoms are prevalent. Although these conditions do not fit the classic description of any specific psychiatric disorder, they often show nonspecific psychiatric symptoms that cross diagnostic boundaries, including intellectual disability, behavioral abnormalities, mood disorders, anxiety disorders, attention deficit, impulse control deficit, and psychosis. Although testing for chromosomal disorders and monogenic Mendelian disorders is well established, testing for common variants is still controversial. The standard concept of genetic testing includes at least three broad criteria that need to be fulfilled before new genetic tests should be introduced: analytical validity, clinical validity, and clinical utility. These criteria are currently not fulfilled for common genomic variants in psychiatric disorders. Further work is clearly needed before genetic testing for common variants in psychiatric disorders should be established.

Distal 10q monosomy: new evidence for a neurobehavioral condition?

Pure distal monosomy of the long arm of chromosome 10 is a rare cytogenetic abnormality. The location and size of the deletions described in this region are variable. Nevertheless, the patients share characteristic facial appearance, variable cognitive impairment and neurobehavioral manifestations. A Minimal Critical Region corresponding to a 600 kb Smallest Region of deletion Overlap (SRO) has been proposed. In this report, we describe four patients with a distal 10q26 deletion, who displayed attention-deficit/hyperactivity disorders (ADHD). One of them had a marked behavioral profile and relatively preserved cognitive functions. Interestingly, the SRO was not included in the deleted segment of this patient suggesting that this deletion could contain candidate genes involved in the control of neurobehavioral functions. One of these candidates was the CALY gene, known for its association with ADHD patients and whose expression level was shown to be correlated with neurobehavioral disturbances in varying animal models. This report emphasizes the importance of the behavioral problems as a cardinal feature of the 10q microdeletion syndrome. Haploinsufficiency of CALY could play a crucial role in the development of the behavioral troubles within these patients.

Chromosome 10q deletion del (10)(q26.1q26.3) is associated with cataract

Distal 10q deletion syndrome is an uncommon chromosomal disorder. Interstitial deletion involving bands 10q25-10q26.1 is extremely rare and few cases have been reported. The characteristic features are facial dysmorphisms, postnatal growth retardation, developmental delay, congenital heart disease, genitourinary anomalies, digital anomalies, and strabismus. We report for the first time a patient with de novo 10q interstitial deletion del (10)(q26.1q26.3) and cataract.

Targetome profiling, pathway analysis and genetic association study implicate miR-202 in lymphomagenesis

BACKGROUND

miRNAs have been implicated in numerous tumorigenic pathways, and previous studies have associated miR-202 dysregulation with various cancer types, including follicular lymphoma.

METHODS

The miR-202 targetome was identified by ribonucleoprotein immunoprecipitation-microarray (RIP-Chip), and functional interactions among identified targets were investigated using the Ingenuity Pathway Analysis tool. We also conducted a population-based genetic association study of a polymorphism within the miR-202 stem-loop sequence and risk of non-Hodgkin lymphoma. In vitro gain-of-function experiments were further conducted to elucidate the functional significance of the variant.

RESULTS

A total of 141 potential members of the miR-202 targetome were identified by a transcriptome-wide RIP-Chip assay. Functional interactions among identified targets suggested that miR-202-regulated genes are involved in biologic pathways relevant for hematologic function and cancer. Consistent with this, a genetic association analysis using human blood samples revealed a significant association between a germline mutation (rs12355840) in the miR-202 precursor sequence and follicular lymphoma risk. An in vitro functional assay further showed that the variant allele resulted in diminished miR-202 levels, possibly by altering precursor-processing efficiency.

CONCLUSIONS

Taken together, our findings suggest that miR-202 is involved in follicular lymphomagenesis.

IMPACT

These findings implicate miR-202 as a potential tumor suppressor in follicular lymphoma and warrant the investigation of miR-202 as a novel biomarker of follicular lymphoma risk.

Headbobber: a combined morphogenetic and cochleosaccular mouse model to study 10qter deletions in human deafness

The recessive mouse mutant headbobber (hb) displays the characteristic behavioural traits associated with vestibular defects including headbobbing, circling and deafness. This mutation was caused by the insertion of a transgene into distal chromosome 7 affecting expression of native genes. We show that the inner ear of hb/hb mutants lacks semicircular canals and cristae, and the saccule and utricle are fused together in a single utriculosaccular sac. Moreover, we detect severe abnormalities of the cochlear sensory hair cells, the stria vascularis looks severely disorganised, Reissner's membrane is collapsed and no endocochlear potential is detected. Myo7a and Kcnj10 expression analysis show a lack of the melanocyte-like intermediate cells in hb/hb stria vascularis, which can explain the absence of endocochlear potential. We use Trp2 as a marker of melanoblasts migrating from the neural crest at E12.5 and show that they do not interdigitate into the developing strial epithelium, associated with abnormal persistence of the basal lamina in the hb/hb cochlea. We perform array CGH, deep sequencing as well as an extensive expression analysis of candidate genes in the headbobber region of hb/hb and littermate controls, and conclude that the headbobber phenotype is caused by: 1) effect of a 648 kb deletion on distal Chr7, resulting in the loss of three protein coding genes (Gpr26, Cpmx2 and Chst15) with expression in the inner ear but unknown function; and 2) indirect, long range effect of the deletion on the expression of neighboring genes on Chr7, associated with downregulation of Hmx3, Hmx2 and Nkx1.2 homeobox transcription factors. Interestingly, deletions of the orthologous region in humans, affecting the same genes, have been reported in nineteen patients with common features including sensorineural hearing loss and vestibular problems. Therefore, we propose that headbobber is a useful model to gain insight into the mechanisms underlying deafness in human 10qter deletion syndrome.

Rapid aneuploidy diagnosis of partial trisomy 7q (7q34→qter) and partial monosomy 10q (10q26.12→qter) by array comparative genomic hybridization using uncultured amniocytes

OBJECTIVE

To present rapid aneuploidy diagnosis (RAD) of partial trisomy 7q (7q34→qter) and partial monosomy 10q (10q26.12→qter) by array comparative genomic hybridization (aCGH) using uncultured amniocytes.

CASE REPORT

A 34-year-old, gravida 2, para 1, woman underwent amniocentesis at 20 weeks of gestation because of a previous mentally retarded child with an unbalanced reciprocal translocation inherited from the carrier father who had a karyotype of 46,XY,t(7;10) (q34;q26.12). Her first child was initially found to have a normal karyotype by routine cytogenetic analysis, but a cryptic chromosomal abnormality was subsequently diagnosed by aCGH. During this pregnancy, RAD by oligonucleotide-based aCGH using uncultured amniocytes revealed a 16.4-Mb duplication of 7q34-q36.3 and a 12.7-Mb deletion of 10q26.12-q26.3. Conventional cytogenetic analysis using cultured amniocytes revealed a karyotype of 46,XX,der(10)t(7;10)(q34;q26.12)pat. The parents elected to terminate the pregnancy. A malformed female fetus was delivered with a high prominent forehead, hypertelorism, epicanthic folds, a broad depressed nasal bridge, a prominent nose with anteverted nostrils, micrognathia, a short neck, large low-set ears, clinodactyly, small big toes, and normal female external genitalia.

CONCLUSION

aCGH is a useful tool for RAD of subtle chromosomal rearrangements in pregnancy, especially under the circumstance of a previous abnormal child with an unbalanced translocation derived from a parental subtle reciprocal translocation.

Aetiology of severe mental retardation and further genetic analysis by high-resolution microarray in a population-based series of 6- to 17-year-old children

AIM

To investigate the prevalence, co-morbidities and aetiologies of severe mental retardation (SMR) in a cohort of Swedish children and to further penetrate aetiologies in the group with undetermined causes by application of updated clinical-genetic methods.

METHODS

The study was population-based and included children living in the County of Halland in western Sweden in 2004 (born 1987-1998; 46,000 children). Patients were identified through habilitation centres, paediatric clinics and school health services. Patients with unclear prenatal aetiology were investigated with single nucleotide polymorphism (SNP)-array.

RESULTS

Severe mental retardation was identified in 133 children from 132 families, corresponding to a prevalence of 2.9 per 1000 children. There were more males than females (90:43).The aetiology was prenatal in 82 (62%), perinatal in 14 (10%) and postnatal in 8 (6%). In 29 (22 %) children, mainly males with autism, the cause could not be related to the time of birth. In the prenatal group, genetic causes dominated, but still 23 children remained undiagnosed; in 5/19 of these patients, a diagnosis could be made after SNP-array analysis. One or more associated neurological handicaps were found in more than half of the children.

CONCLUSION

Prevalence and co-morbidity were similar to previous Scandinavian studies. High-resolution chromosomal micro-array techniques are valuable diagnostic tools, reducing the number of patients with unexplained SMR.

Newborn with prenatally diagnosed choroidal fissure cyst and panhypopituitarism and review of the literature

Little has been reported on fetal diagnosis of choroidal fissure cysts and prediction of the clinical complications that can result. We describe the case of a near-term male infant with prenatally diagnosed choroidal fissure cyst and bilateral clubfeet. His prolonged course in the neonatal intensive care nursery was marked by severe panhypopituitarism, late-onset diabetes insipidus, placement of a cystoperitoneal shunt, and episodes of sepsis. Postnatal genetic evaluation also revealed an interstitial deletion involving most of band 10q26.12 and the proximal half of band 10q26.13. The patient had multiple readmissions for medical and surgical indications and died at 6 months of age. This case represents the severe end of the spectrum of medical complications for children with choroidal fissure cysts. It highlights not only the importance of comprehensive evaluation and multidisciplinary management and counseling in such cases, but also the need for heightened vigilance in these patients.

De novo 325 kb microdeletion in chromosome band 10q25.3 including ATRNL1 in a boy with cognitive impairment, autism and dysmorphic features

We provide the first description of a patient with a heterozygous deletion of the Attractin-like (ATRNL1) gene. The patient presented with a novel and distinctive phenotype comprising dysmorphic facial appearance, ventricular septal defect, toe syndactyly, radioulnar synostosis, postnatal growth retardation, cognitive impairment with autistic features, and ataxia. A 325 kb de novo deletion in ATRNL1 was demonstrated using SNP microarray and confirmed by FISH analysis using BAC probes. Sequence analysis of the undeleted allele did not identify any alterations, suggesting that the phenotype was the result of haploinusfficiency. ATRNL1 and its paralog ATRN are highly conserved transmembrane proteins thought to be involved in cell adhesion and signalling events. The phenotype of mice with homozygous Atrn mutations overlaps considerably with the features observed in our patient. We therefore postulate that our patient's phenotype is caused by the deletion of ATRNL1, and provide further insight into the role of ATRNL1 in human development.

Chromosome r(10)(p15.3q26.12) in a newborn child: case report

Background

Ring chromosome 10 is a rare cytogenetic finding. Of the less than 10 reported cases we have found in the literature, none was characterized using high-resolution microarray analysis. Ring chromosomes are frequently unstable due to sister chromatid exchanges and mitotic failures. When mosaicism is present, the interpretation of genotype-phenotype correlations becomes extremely difficult.

Results

We report on a newborn girl with growth retardation, microcephaly, congenital heart defects, dysmorphic features and psychomotor retardation. Karyotyping revealed a non-mosaic apparently stable ring chromosome 10 replacing one of the normal homologues in all analyzed metaphases. High-resolution oligonucleotide microarray analysis showed a de novo approximately 12.5 Mb terminal deletion 10q26.12 -> qter and a corresponding 285 kb terminal deletion of 10pter -> p15.3.

Conclusion

This case demonstrates that an increased nuchal translucency thickness detected by early ultrasonography should preferably lead to not only QF-PCR for the diagnosis of Down syndrome but also karyotyping. In the future, microarray analysis, which needs further evaluation, might become the method of choice. The clinical phenotype of our patient was in agreement with that of patients with a terminal 10q deletion. For the purpose of genotype-phenotype analysis, there seems to be no need for a "ring syndrome" concept.

Identification of critical regions for clinical features of distal 10q deletion syndrome

Array comparative genomic hybridization studies were performed to further characterize cytogenetic abnormalities found originally by karyotype and fluorescence in situ hybridization in five clinical cases of distal 10q deletions, including several with complex cytogenetic rearrangements and one with a partial male-to-female sex-reversal phenotype. These results have enabled us to narrow the previously proposed critical regions for the craniofacial, urogenital, and neuropsychiatric disease-related manifestations associated with distal 10q deletion syndrome. Furthermore, we propose that haploinsufficiency of the DOCK1 gene may play a crucial role in the pathogenesis of the 10q deletion syndrome. We hypothesize that alteration of DOCK1 and/or other genes involved in regulation and signaling of multiple pathways can explain the wide range of phenotypic variability between patients with similar or identical cytogenetic abnormalities.

Molecular (SNP) analyses of overlapping hemizygous deletions of 10q25.3 to 10qter in four patients: evidence for HMX2 and HMX3 as candidate genes in hearing and vestibular function

We report on the analyses of four unrelated patients with de novo, overlapping, hemizygous deletions of the long arm of chromosome 10. These include two small terminal deletions (10q26.2 to 10qter), a larger terminal deletion (10q26.12 to 10qter), and an interstitial deletion (10q25.3q26.13). Single nucleotide polymorphism (SNP) studies (Illumina 550 K) established that these deletions resulted in the hemizygous loss of approximately 6.1, approximately 6.1, approximately 12.5, and approximately 7.0 Mb respectively. Additionally, these data establish that Patients 1, 2, and 3 share common, distal, hemizygous deleted regions of 6.09 Mb containing 37 RefSeq genes. Patients 3 and 4 share a 2.52 Mb deleted region corresponding to the proximal deleted region of Patient 3 and the distal deleted region of Patient 4. This common, hemizygous region contains 20 RefSeq genes including two H6 family homeobox genes (HMX2 and HMX3). Based on previous reports that Hmx2/Hmx3 knockout mice have vestibular anomalies, we propose that hemizygous deletions of HMX2 and HMX3 are responsible for the inner ear malformations observed from CT images, vestibular dysfunction, and congenital sensorineural hearing loss found in Patients 3 and 4.

ABCC2 haplotype is not associated with drug-resistant epilepsy

Several studies have investigated the association between the ABCB1 polymorphism and drug-resistant epilepsy. However, the effect of ABCC2 polymorphisms on anti-epileptic drug (AED) responsiveness remains unknown. The ABCC2 polymorphisms have been genotyped in 279 Japanese epileptic patients treated with AEDs. The association between the AED responsiveness and the polymorphisms was estimated by a haplotype-based analysis. No genotype or haplotype was associated with drug-resistant epilepsy. On the other hand, the delGCGC haplotype at G-1774delG, C-24T, G1249A and C3972T was over represented among the epileptic patients with a complication of mental retardation in comparison with those without (32.4% vs 22.0%; P=0.009); and the G-1774delG allele was also associated with mental retardation (P=0.03). No association between the ABCC2 genotypes or haplotypes, and the responsiveness of AEDs was observed, although this finding was inconclusive because of the small sample size.

Calcyon mRNA expression in the frontal-striatal circuitry and its relationship to vesicular processes and ADHD

Background

Calcyon is a single transmembrane protein predominantly expressed in the brain. Very recently, calcyon has been implicated in clathrin mediated endocytosis, a critical component of synaptic plasticity. At the genetic level, preliminary evidence supports an association between attention-deficit/hyperactivity disorder (ADHD) and polymorphisms in the calcyon gene. As little is known about the potential role of calcyon in ADHD, animal models may provide important insights into this issue.

Methods

We examined calcyon mRNA expression in the frontal-striatal circuitry of three-, five-, and ten-week-old Spontaneously Hypertensive Rats (SHR), the most commonly used animal model of ADHD, and Wistar-Kyoto (WKY; the strain from which SHR were derived). As a complement, we performed a co-expression network analysis using a database of mRNA gene expression profiles of multiple brain regions in order to explore potential functional links of calcyon to other genes.

Results

In all age groups, SHR expressed significantly more calcyon mRNA in the medial prefrontal and orbital frontal cortices than WKY rats. In contrast, in the motor cortex, dorsal striatum and nucleus accumbens, calcyon mRNA expression was only significantly elevated in SHR in younger animals. In both strains, calcyon mRNA levels decreased significantly with age in all regions studied. In the co-expression network analysis, we found a cluster of genes (many of them poorly studied so far) strongly connected to calcyon, which may help elucidate its role in the brain. The pair-wise relations of calcyon with other genes support its involvement in clathrin mediated endocytosis and, potentially, some other membrane/vesicular processes. Interestingly, no link was found between calcyon and the dopamine D1 receptor, which was previously shown to interact with the C-terminal of calcyon.

Conclusion

The results indicate an alteration in calcyon expression within the frontal-striatal circuitry of SHR, especially in areas involved in cognitive processes. These findings extend our understanding of the molecular alterations in SHR, a heuristically useful model of ADHD.

Familial complex 3q;10q rearrangement unraveled by subtelomeric FISH analysis

In recent years, subtelomeric rearrangements have been identified as a major cause of multiple congenital anomalies/mental retardation syndromes. Currently, more than 2,500 individuals with mental retardation have been tested and reported in whom subtelomeric rearrangements were detected ranging from 2% to 29%. Therefore, subtelomeric FISH analysis is indicated as a second tier test after high-resolution G-banding analysis in patients with otherwise unexplained developmental delay/mental retardation and/or multiple congenital anomalies. We describe a patient and her three maternal female cousins, all showing an undiagnosed MCA/MR syndrome, associated with the same complex subtelomeric rearrangement. Subtelomeric FISH testing performed between 3(1/2) and 18 years after the initial karyotype showed, in all four patients, distal trisomy 3q and distal monosomy 10q as follows: 46,XX,ish der(10)t(3;10)(q29;q26.3)mat(D10S2488+,D10S2490-, D3S1272+,D10Z1+). Parental subtelomeric FISH analysis showed that the proposita's mother and three of four brothers and one of two sisters had a cryptic balanced 3:10 telomere translocation. The three brothers with the balanced translocation were father to one each of the three proband's cousins. All four affected girls showed a similar phenotype with pre/postnatal growth retardation, microcephaly, severe developmental delay/mental retardation, poor/absent speech, and a distinct pattern of malformation. On examination there were coarsening of facial features with low fronto-temporal hairline; thick eyebrows; bilateral epicanthal folds; hypertelorism; prominent nose with squared nasal root and narrow alar base; low-set posteriorly rotated large ears with a prominent anthelix; high arched palate; prominent chin; hands/feet brachydactyly; bilateral squint; hypotonia; and muscle hypotrophy. A slow overall improvement was seen in all patients over time. To our knowledge, this complex subtelomeric rearrangement in our patients has never been reported so far. Monosomy 10q has recently been described either isolated or as part of a complex rearrangement involving telomeres other than the 3q. Trisomy 3q29 has not yet been reported, but our patients resembled cases with 3q26 trisomy suggesting that the critical region of duplication for this phenotype is in 3q29.

A subterminal deletion of the long arm of chromosome 10: a clinical report and review

We report on a girl with mental retardation, dysmorphic features, and behavioral problems. A small terminal deletion of the long arm of chromosome 10 was detected by subtelomeric fluorescence in situ hybridization (FISH) studies in all analyzed metaphases. The deletion was shown to be a de novo terminal deletion of approximately 6.1 Mb, with the deletion breakpoint localized at band 10q26.2, between BAC probes RP11-498K22 and RP11-42K2. A subterminal 10q deletion as found in the present patient has, to our knowledge, only been reported in 15 patients (including 8 familial cases). We review the clinical and behavioral phenotype of these patients with "pure" subterminal 10q deletion.

Congenital indifference to pain and deletion of chromosome 10q-: new association

We describe a case of a de novo terminal deletion of the long arm of chromosome 10 with the novel feature of congenital indifference to pain in a 2-year 10-month-old boy. Relative indifference to pain defined by a lack of emotional response to pain has not been described previously in association with the terminal deletion of the long arm of chromosome 10.