Del(10)(q22.3q24.1) associated with juvenile polyposis

Juvenile polyps are the most frequent gastrointestinal polyps with a malignant potential for which the genetic basis is unknown. Juvenile polyps, with a normal epithelium but hypertrophic lamina propria, are histologically quite distinct from adenomatous polyps which have dysplastic changes in epithelial nuclei. Furthermore, the adenomatous polyposis coli (APC) gene on Chr 5, mutated somatically in adenomatous polyps and mutated in the germline of patients with familial adenomatous polyposis, is not linked to hereditary juvenile polyposis. We provide the first report indicating that a tumor suppressor gene associated with juvenile polyposis may be located at 10q22.3q24.1. Cytogenetic studies of a patient with juvenile polyposis and multiple congenital abnormalities of the head, extremities, and abdomen revealed a de novo interstitial deletion of Chr 10 as the only defect, del(10)(10q22.3q24.1). Am. J. Med. Genet. 70:361–364, 1997. © 1997 Wiley-Liss, Inc.     

Clinical and molecular characterization of individuals with recurrent genomic disorder at 10q22.3q23.2

Alliman S, Coppinger J, Marcadier J, Thiese H, Brock P, Shafer S, Weaver C, Asamoah A, Leppig K, Dyack S, Morash B, Schultz R, Torchia BS, Lamb AN, Bejjani BA. Clinical and molecular characterization of individuals with recurrent genomic disorder at 10q22.3q23.2. The identification of genomic imbalances in young patients can affect medical management by allowing early intervention for developmental delay and by identifying patients at risk for unexpected medical complications. Using a 105K‐feature oligonucleotide array, we identified a 7.25 Mb deletion at 10q22.3q23.2 in six unrelated patients. Deletions of this region have been described in individuals with cognitive and behavioral abnormalities, including autistic features, and may represent a recurring genetic syndrome. All four patients in this study for whom clinical information was available had mild dysmorphic features and three had developmental delay. Of note is the emerging clinical phenotype in these individuals with similar dysmorphic features such as macrocephaly, hypertelorism, and arachnodactyly, and neurodevelopmental delay that includes failure to thrive, hypotonia, and feeding difficulties in the neonatal period, and receptive and expressive language delay with global neurodevelopmental delay after the neonatal period. However, there is no pattern of abnormalities, craniofacial, behavioral, or otherwise, that would have aroused clinical suspicion of a specific syndrome. Finally, the patients' deletions encompass BMPR1A but not PTEN, and these patients may be at risk for colon cancer and should be referred for appropriate prophylactic care and surveillance. Of the two patients in this study who had colonoscopy following the array results, neither had polyps. Therefore, the magnitude of the increased risk for colon cancer is currently unknown.     

Tibial hemimelia in Langer-Giedion syndrome with 8q23.1-q24.12 interstitial deletion

Langer-Giedion syndrome (LGS) (OMIM 150230) is defined as a contiguous gene syndrome caused by loss of functional copies of the TRPS1 and EXT1 genes usually secondary to 8q microdeletion. Tibial hemimelia (TH) is the least common lower limb deficiency characterized by hypoplasia of the tibia with relatively intact fibula. We describe the third report of LGS with bilateral TH and an 8q23.1-q24.12 interstitial deletion. It is not possible to exclude that this association is fortuitous, but our report reinforces the suggestion of a putative gene involved in limb development in this chromosomal region interval.     

Monosomy 18q syndrome and atypical Rett syndrome in a girl with an interstitial deletion (18)(q21.1q22.3)

We describe a 6 1/2-year-old girl with an interstitial deletion of chromosome arm 18q (18q21.1q22.3). Her clinical manifestations are a combination of those found in monosomy 18q syndrome and those of Rett syndrome. Cytogenetic analysis demonstrated a deletion of the long arm of chromosome 18, defined by molecular analysis with polymorphic markers as a de novo interstitial deletion, paternally derived. The findings typical of the 18q- syndrome included mental retardation, midface hypoplasia, and hypoplasia of labia majora, and those typical of Rett syndrome were severe mental retardation, autistic behavior, inappropriate hand-washing movements, epilepsy, attacks of sighing and hyperventilation, and progressive scoliosis since the age of 5 years. She did not have microcephaly, and the mental delay was obvious from an early age without a period of normal development, which makes the diagnosis of Rett syndrome atypical. Previously, a girl with mosaicism for a monosomy 18q associated with Rett syndrome has been described. That girl had a terminal deletion of chromosome 18q, which seems to coincide in part with that in the present girl. It is possible that genes in the distal region of 18q are involved in the etiology of Rett syndrome.     

BMPR1A is a candidate gene for congenital heart defects associated with the recurrent 10q22q23 deletion syndrome

Congenital heart defects (CHD) are associated with the recurrent 10q22q23 deletion syndrome and with partially overlapping distal 10q23.2.q23.31 microdeletions. We report on a de novo intragenic deletion of the BMPR1A gene in a normally developing adolescent boy with short stature, delayed puberty, facial dysmorphism and an atrioventricular septal defect. Based on this finding, complemented with computational prioritization data and molecular evidence in literature, the critical region for CHD on 10q23 can be downsized to a single gene, BMPR1A. Although loss-of-function mutations in BMPR1A typically result in juvenile polyposis syndrome, none of the patients with the typical 10q22q23 microdeletion syndrome, comprising this gene, were reported to have juvenile polyposis thus far. We reason that, even in the absence of juvenile polyposis syndrome, sequencing and copy number analysis of BMPR1A should be considered in patients with (atrioventricular) septal defects, especially when associated with facial dysmorphism and anomalous growth.     

Deletion 10q23.2-q23.33 in a patient with gastrointestinal juvenile polyposis and other features of a Cowden-like syndrome

A cytogenetically visible interstitial deletion of chromosome band 10q23 was found in a 6-year-old boy with mental retardation, dysmorphic features, and juvenile polyposis coli. In order to map this patient's deletion physically, we performed fluorescence in situ hybridization by using yeast artificial chromosomes (YACs) in the vicinity of the deletion. Five YACs that span an 11–15 cM region within the deletion were identified. This patient's deletion contains the putative locus for Cowden syndrome and a recently discovered candidate tumor suppressor gene (MMAC1 or PTEN) that has been implicated in the progression of a variety of human malignancies. Furthermore, the deletion is near and possibly overlaps a locus associated with juvenile polyposis. The findings in this patient with a constitutional 10q23 deletion raise the issue of whether there are separate genes in this region that are involved in Cowden syndrome, Bannayan-Riley-Ruvalcaba syndrome, juvenile polyposis, and tumor progression, or whether all of these entities could be due to a single gene. Genes Chromosomes Cancer 21:113–118, 1998. © 1998 Wiley-Liss, Inc.     

Congenital heart defects in the recurrent 2q13 deletion syndrome

The recurrent 2q13 deletion syndrome is a rare genetic disorder associated with developmental delay, cardiac and urogenital malformations, and minor facial anomalies. Congenital heart defects (CHDs) are the most frequent malformations associated with del2q13. Experimental studies in zebrafish suggest that two genes mapping within the 2q13 critical region (FBLN7 and TMEM87B) could confer susceptibility to congenital heart defects in affected individuals. We reviewed the cardiac characteristics in four patients with 2q13 deletion admitted to our hospitals, and in published patients. Two of our patients had congenital heart defects, consisting in partial anomalous pulmonary venous connection, ostium secundum atrial septal defect ostium secundum, and small muscular ventricular septal defect in one of them, and aortic valve insufficiency with partial fusion of two commissures (incomplete bicuspid aortic valve) and mitral valve insufficiency due to trivial mitral valve prolapse in the other. The anatomic types of CHD in del2q13 syndrome are highly variable and distributed widely, including laterality defects, complex atrioventricular septal defect, septal anomalies, and cardiomyopathies. Cardiac evaluation should be part of the clinical workup at diagnosis of 2q13 deletion.     

Reciprocal deletion and duplication at 2q23.1 indicates a role for MBD5 in autism spectrum disorder

Copy number variations associated with abnormal gene dosage have an important role in the genetic etiology of many neurodevelopmental disorders, including intellectual disability (ID) and autism. We hypothesize that the chromosome 2q23.1 region encompassing MBD5 is a dosage-dependent region, wherein deletion or duplication results in altered gene dosage. We previously established the 2q23.1 microdeletion syndrome and report herein 23 individuals with 2q23.1 duplications, thus establishing a complementary duplication syndrome. The observed phenotype includes ID, language impairments, infantile hypotonia and gross motor delay, behavioral problems, autistic features, dysmorphic facial features (pinnae anomalies, arched eyebrows, prominent nose, small chin, thin upper lip), and minor digital anomalies (fifth finger clinodactyly and large broad first toe). The microduplication size varies among all cases and ranges from 68 kb to 53.7 Mb, encompassing a region that includes MBD5, an important factor in methylation patterning and epigenetic regulation. We previously reported that haploinsufficiency of MBD5 is the primary causal factor in 2q23.1 microdeletion syndrome and that mutations in MBD5 are associated with autism. In this study, we demonstrate that MBD5 is the only gene in common among all duplication cases and that overexpression of MBD5 is likely responsible for the core clinical features present in 2q23.1 microduplication syndrome. Phenotypic analyses suggest that 2q23.1 duplication results in a slightly less severe phenotype than the reciprocal deletion. The features associated with a deletion, mutation or duplication of MBD5 and the gene expression changes observed support MBD5 as a dosage-sensitive gene critical for normal development.     

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.     

A novel interstitial deletion of 10q24.2q24.32 in a patient with renal coloboma syndrome

Renal coloboma syndrome (RCS) is considered to be a rare autosomal dominant inherited disorder characterized by renal malformations and optic disc coloboma. Ocular anomalies range from asymptomatic abnormalities in retinal blood vessel patterning to large excavations of the optic nerve associated with reduced visual acuity. Commonly observed manifestations of the kidney are renal hypoplasia and vesicoureteric reflux leading to end-stage renal disease. Mutations in the PAX2 gene on chromosome 10 have been identified in patients with RCS. Up to date, nucleotide substitutions, insertions, small deletions, one de novo translocation, and one 240 kb deletion of the coding region of the PAX2 gene have been described to be responsible for RCS.We report here a new case of a patient with RCS due to a deletion of 3.8 Mb on chromosome 10q. Deletions on the long arm of chromosome 10 harboring the PAX2 gene seem to be a rare cause for RCS. Nevertheless, array-CGH testing should represent an important and valuable addition to PAX2 gene sequencing in diagnostic of RCS.     

Frontonasal dysplasia, callosal agenesis, basal encephalocele, and eye anomalies syndrome with a partial 21q22.3 deletion

We describe a girl with a phenotype characterized by frontonasal dysplasia, callosal agenesis, basal encephalocele, and eye anomalies who presents a 46,XX,r(21) karyotype. Array-comparative genomic hybridization using the Afflymetrix 100K DNA oligoarray set showed an interstitial deletion 21q22.3 of approximately 219 kb. Conventional karyotype of both parents was normal, and it was not possible to perform the molecular studies. In this report we raise the hypothesis that the deleted genes located at 21q22.3 could account to the phenotype.     

16q21 is critical for 16q deletion syndrome

A 1-year-old girl with an interstitial deletion of the long arm of chromosome 16 is reported. She was characterized by a distinct craniofacial dysmorphism, meningoencephalocele, mild hydrocephalus, short neck, broad great toes and abnormally positioned toes. High resolution GTG and RBG banding analyses revealed a karyotype: 46,XX,del(16) (q13q22) de novo. An analysis of the smallest region of overlap revealed that the critical band region for 16q deletion syndrome is 16q21.