Molecular and clinical delineation of the 17q22 microdeletion phenotype

Deletions involving 17q21-q24 have been identified previously to result in two clinically recognizable contiguous gene deletion syndromes: 17q21.31 and 17q23.1-q23.2 microdeletion syndromes. Although deletions involving 17q22 have been reported in the literature, only four of the eight patients reported were identified by array-comparative genomic hybridization (array-CGH) or flourescent in situ hybridization. Here, we describe five new patients with 1.8-2.5-Mb microdeletions involving 17q22 identified by array-CGH. We also present one patient with a large karyotypically visible deletion involving 17q22, fine-mapped to ∼8.2 Mb using array-CGH. We show that the commonly deleted region in our patients spans 0.24 Mb and two genes; NOG and C17ORF67. The function of C17ORF67 is not known, whereas Noggin, the product of NOG, is essential for correct joint development. In common with the 17q22 patients reported previously, the disease phenotype of our patients includes intellectual disability, attention deficit hyperactivity disorder, conductive hearing loss, visual impairment, low set ears, facial dysmorphology and limb anomalies. All patients displayed NOG-related bone and joint features, including symphalangism and facial dysmorphology. We conclude that these common clinical features indicate a novel clinically recognizable, 17q22 contiguous microdeletion syndrome.European Journal of Human Genetics advance online publication, 30 January 2013; doi:10.1038/ejhg.2012.306

Pericentric inversion of chromosome 18 in parents leading to a phenotypically normal child with segmental uniparental disomy 18

In this study, we report a familial inversion of chromosome 18, inv(18)(p11.31q21.33), in both members of a consanguineous couple. Their first child had inherited one balanced pericentric inversion along with a recombinant chromosome 18 resulting in dup(18q)/del(18p), and had mild dysmorphic features in the absence of mental and developmental retardation. The second child had received two recombinant chromosomes 18, from the mother a derivative chromosome 18 with dup(18p)/del(18q) and from the father a derivative chromosome 18 with dup(18q)/del(18p). The aberration was prenatally detected; however, as the two opposite aneuploidies were thought to compensate each other, the family decided to carry on with the pregnancy, knowing that uniparental disomy for the segments outside the inversion could have an adverse influence on the development of the child. Uniparental disomy was confirmed by SNP arrays. The child, who has been followed up until the age of 20 months, is healthy and normal. It seems to be the first reported case with two opposite recombinant chromosomes that compensate each other and lead to segmental uniparental disomy for two segments on the chromosome, one maternal and the other paternal

Recurrent Deletion of ZNF630 at Xp11.23 Is Not Associated With Mental Retardation How to Cite this Article

ZNF630 is a member of the primate-specific Xp11 zinc finger gene cluster that consists of six closely related genes, of which ZNF41, ZNF81, and ZNF674 have been shown to be involved in mental retardation. This suggests that mutations of ZNF630 How to Cite this Article: 638 might influence cognitive function. Here, we detected 12 ZNF630 deletions in a total of 1,562 male patients with mental retardation from Brazil, USA, Australia, and Europe. The breakpoints were analyzed in 10 families, and in all cases they were located within two segmental duplications that share more than 99% sequence identity, indicating that the deletions resulted from non-allelic homologous recombination. In 2,121 healthy male controls, 10 ZNF630 deletions were identified. In total, there was a 1.6-fold higher frequency of this deletion in males with mental retardation as compared to controls, but this increase was not statistically significant (P-value ¼ 0.174). Conversely, a 1.9-fold lower frequency of ZNF630 duplications was observed in patients, which was not significant either (P-value ¼ 0.163). These data do not show that ZNF630 deletions or duplications are associated with mental retardation.