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The direct transmission of microscopically visible unbalanced chromosome abnormalities (UBCAs) is rare and usually has phenotypic consequences. Here we report four families in which a normal phenotype was initially found in one or more family members. Each UBCA was interpreted with regard to overlapping examples and factors previously associated with transmitted imbalances including incidental ascertainment, low gene density, benign copy number variation (CNV) content, and gene relatedness. A 4.56 Mb deletion of 8p23.1‐p23.2 was thought to be causal in the affected proband but showed incomplete penetrance in her mother and sibling (Family 1). Incomplete penetrance was also associated with a 10.88 Mb duplication of 13q21.31‐q22.1 (Family 3) and dosage insensitivity with a 17.6 Mb deletion of 22pter‐q11.21 (Family 4) that were both ascertained at prenatal diagnosis and each found in 4 unaffected family members. The 22pter‐q11.21 deletion is part of a region with high benign CNV content and supports the mapping of cat eye syndrome to a 600 kb interval of 22q11.1‐q11.21. Low gene densities of less than 2.0 genes/Mb were found in each of these three families but only after segmentally duplicated genes were excluded from the deletions of 8p and 22q. In contrast, gene density was average and variable expressivity associated with a 3.59 Mb duplication of 8p23.1 incidentally ascertained for paternal infertility (Family 2). Our results indicate that a greater degree of direct parental transmission, incomplete penetrance, and variable expression are features of both sub‐microscopic CNVs and UBCAs with relatively low gene and high benign CNV content. [ABSTRACT FROM AUTHOR]

Background Microdeletions of 2q23.1 disrupting MBD5 and loss of function mutations of MBD5 cause MBD5-Associated Neurodevelopmental disorders ( MAND). Nearly all reported patients have been isolated cases of de novo origin. Methods This study investigates three families with inherited MBD5 mutations from three different Regional Genetics Centres in the UK. Results Two of the parents in the study had MBD5 deletions in a mosaic form. The parent with an MBD5 deletion in an apparently nonmosaic form has a psychiatric disorder in the absence of developmental delay or dysmorphism. Conclusions Inherited forms of MBD5 deletions are rare, but do occur, especially in a mosaic form. The phenotypic spectrum of MAND may be wider than previously thought. [ABSTRACT FROM AUTHOR]

A variety of ocular anomalies have been described in the rare ring 14 and 14q terminal deletion syndromes, yet the character, prevalence, and extent of these anomalies are not well defined. Identification of these ocular anomalies can be central to providing diagnoses and facilitating optimal individual patient management. We report a child with a 14q32.31 terminal deletion and ring chromosome formation, presenting with severe visual impairment secondary to significant bilateral coloboma and microphthalmia. This patient is compared to previously reported patients with similar ocular findings and deletion sizes to further refine a locus for coloboma in the 14q terminal region. Those with ring formation and linear deletions are compared and the possibility of ring formation affecting the proximal 14q region is discussed. This report highlights the severity of ocular anomalies that can be associated with ring 14 and 14q terminal deletion syndromes and reveals the limited documentation of ocular examination in these two related syndromes. This suggests that many children with these genetic changes do not undergo an ophthalmology examination as part of their clinical assessment, yet it is only when this evaluation becomes routine that the true prevalence and extent of ocular involvement can be defined. This report therefore advocates for a thorough ophthalmological exam in children with ring 14 or 14q terminal deletion syndrome. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Submicroscopic deletions within chromosome 1q24q25 are associated with a syndromic phenotype of short stature, brachydactyly, learning difficulties, and facial dysmorphism. The critical region for the deletion phenotype has previously been narrowed to a 1.9Mb segment containing 13 genes. We describe two further patients with 1q24 microdeletions and the skeletal phenotype, the first of whom has normal intellect, whereas the second has only mild learning impairment. The deletion in the first patient is very small and further narrows the critical interval for the striking skeletal aspects of this condition to a region containing only Dynamin 3 (DNM3) and two microRNAs that are harbored within intron 14 of this gene: miR199 and miR214. Mouse studies raise the possibility that these microRNAs may be implicated in the short stature and skeletal abnormalities of this microdeletion condition. The deletion in the second patient spans the previously reported critical region and indicates that the cognitive impairment may not always be as severe as previous reports suggest. [ABSTRACT FROM AUTHOR]

The 8p23.1 duplication syndrome (8p23.1 DS) is a recurrent genomic condition with an estimated prevalence of 1 in 58,000. The core 3.68 Mb duplication contains 32 genes of which five are currently candidates for the phenotypic features. Here we describe four patients and five families with eight microduplications of 8p23.1 ranging from 187 to 1082 kb in size and one atypical duplication of 4 Mb. These indicate that a minimal region of overlap (MRO) in medial 8p23.1 can give rise to features of 8p23.1 DS including developmental delay, dysmorphism, macrocephaly and otitis media, but not congenital heart disease (CHD). This MRO spans 776 kb (chr8:10,167,881-10,943,836 hg19) and contains SOX7 and seven of the other 32 core 8p23.1 DS genes. In centromeric 8p23.1, microduplications including GATA4 can give rise to non-syndromic CHD but the clinical significance of two smaller centromeric microduplications without GATA4 was uncertain due to severe neurological profiles not usually found in 8p23.1 DS. The clinical significance of three further 8p23.1 microduplications was uncertain due to additional genetic factors without which the probands might not have come to medical attention. Variable expressivity was indicated by the almost entirely unaffected parents in all five families and the mildly affected sibling in one. Intronic interruptions of six genes by microduplication breakpoint intervals had no apparent additional clinical consequences. Our results suggest that 8p23.1 DS is an oligogenetic condition largely caused by the duplication and interactions of the SOX7 and GATA4 transcription factors. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Deletions of the distal 3q22.3 region encompassing the gene forkhead transcription factor FOXL2 ( FOXL2) usually result in intellectual disability (ID) and the highly recognizable blepharophimosis-ptosis-epicanthus inversus syndrome (BPES). We encountered three patients with molecularly defined interstitial deletions distal to the FOXL2 gene. They present with remarkably similar manifestations comprising variable ID, a coarse facial appearance, including prominent nose and eyebrows, hypogonadism and skin pigmentation abnormalities, and they share an approximately 8.8 Mb overlapping 3q24q25 deletion. Interestingly, one of the present patients was described previously in a clinical report with emphasis on her clinical similarity to the Wisconsin syndrome, suggesting that Wisconsin syndrome might be caused by a (micro) deletion within the 3q24q25 region. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

We describe a patient with striking generalized symmetrical enchondromatosis of the tubular bones and a de novo duplication of chromosome 12p11.23 to 12p11.22. The PTHLH gene within this region encodes a ligand for PTHR1: mutations in the gene encoding this receptor are associated with some cases of Ollier disease, several skeletal dysplasias including Blomstrand, Eiken, and Jansen and down-regulation of PTHLH expression in brachydactyly type E. Our findings suggest that abnormal PTHLH-PTHR1 signaling may underly this unusual form of enchondromatosis and indicate that unlike most cases of Ollier disease it is dominantly inherited., (© 2010 Wiley-Liss, Inc.)

Trisomy and tetrasomy of distal chromosome 15q have rarely been reported. Although most of the described patients have some learning difficulties and are overgrown, the phenotype associated with distal trisomy/tetrasomy 15q is uncertain due to the small numbers of reported cases and the common co-occurrence of additional chromosome deletions in many patients with trisomy 15q. We present five individuals with overgrowth, learning difficulties and increased dosage of distal 15q. Partial trisomy 15q was identified in four of these cases. Two were generated through recombination of a parental pericentric inversion and two were generated through malsegregation of a maternal balanced 14;15 reciprocal translocation. In all four cases the trisomy can be considered "pure" as the 14p and 15p monosomies will exert no phenotypic effect. Partial tetrasomy 15q, as the result of an analphoid supernumerary chromosome derived from an inverted duplication of distal 15q, was identified in the fifth patient. In addition to the overgrowth and learning difficulties, all five had a characteristic facial appearance and three had renal anomalies. The gestalt consists of a long, thin face with a prominent chin and nose. Renal anomalies included renal agenesis, horseshoe kidney, and hydronephrosis. We provide further support for a distinct "15q overgrowth syndrome" caused by either trisomy or tetrasomy resulting in increased dosage of distal 15q. In addition we propose that renal anomalies and a distinctive facial appearance be considered major features of this condition., ((c) 2009 Wiley-Liss, Inc.)

We reascertained a family in which first cousins were affected by Angelman syndrome and Prader-Willi syndrome. A paracentric inversion of 15q11-q15 had previously been reported in this family but we show, using fluorescence in situ hybridization (FISH), that the rearrangement segregating in this family is not a paracentric inversion but an inverted intrachromosomal insertion, inv ins(15)(q15q13q11.2). We also describe a further recombinant resulting in a maternal duplication of the Prader-Willi/Angelman critical region. This family illustrates the importance of distinguishing paracentric inversions from intrachromosomal insertions., (Copyright 2004 Wiley-Liss, Inc.)