Identification of rare genetic variants in patients with intellectual disability (ID) has been greatly accelerated by advances in next generation sequencing technologies. However, due to small numbers of patients, the complete phenotypic spectrum associated with pathogenic variants in single genes is still emerging. Among these genes is ZBTB18 (ZNF238), which is deleted in patients with 1q43q44 microdeletions who typically present with ID, microcephaly, corpus callosum (CC) abnormalities, and seizures. Here we provide additional evidence for haploinsufficiency or dysfunction of the ZBTB18 gene as the cause of ID in five unrelated patients with variable syndromic features who underwent whole exome sequencing revealing separate de novo pathogenic or likely pathogenic variants in ZBTB18 (two missense alterations and three truncating alterations). The neuroimaging findings in our cohort (CC hypoplasia seen in 4/4 of our patients who underwent MRI) lend further support for ZBTB18 as a critical gene for CC abnormalities. A similar phenotype of microcephaly, CC agenesis, and cerebellar vermis hypoplasia has been reported in mice with central nervous system-specific knockout of Zbtb18. Our five patients, in addition to the previously described cases of de novo ZBTB18 variants, add to knowledge about the phenotypic spectrum associated with ZBTB18 haploinsufficiency/dysfunction.

Most obstetricians offer CF carrier screening and will refer to genetic counseling services at times. However, we identified a deficiency of information in a concerning percentage of practitioners. This deficiency could be improved by targeted and readily accessible educational efforts, especially for obstetricians not affiliated with academia.

We report on a 6-month-old girl with two apparent cell lines; one with trisomy 21, and the other with paternal genome-wide uniparental isodisomy (GWUPiD), identified using single nucleotide polymorphism (SNP) based microarray and microsatellite analysis of polymorphic loci. The patient has Beckwith-Wiedemann syndrome (BWS) due to paternal uniparental disomy (UPD) at chromosome location 11p15 (UPD 11p15), which was confirmed through methylation analysis. Hyperinsulinemic hypoglycemia is present, which is associated with paternal UPD 11p15.5; and she likely has medullary nephrocalcinosis, which is associated with paternal UPD 20, although this was not biochemically confirmed. Angelman syndrome (AS) analysis was negative but this testing is not completely informative; she has no specific features of AS. Clinical features of this patient include: dysmorphic features consistent with trisomy 21, tetralogy of Fallot, hemihypertrophy, swirled skin hyperpigmentation, hepatoblastoma, and Wilms tumor. Her karyotype is 47,XX,+21[19]/46,XX[4], and microarray results suggest that the cell line with trisomy 21 is biparentally inherited and represents 40-50% of the genomic material in the tested specimen. The difference in the level of cytogenetically detected mosaicism versus the level of mosaicism observed via microarray analysis is likely caused by differences in the test methodologies. While a handful of cases of mosaic paternal GWUPiD have been reported, this patient is the only reported case that also involves trisomy 21. Other GWUPiD patients have presented with features associated with multiple imprinted regions, as does our patient.

BackgroundGenetic testing is increasingly used as a tool throughout the health care system. In 2011 the number of clinically available genetic tests is approaching 2,000, and wide variation exists between these tests in their sensitivity, specificity, and clinical implications, as well as the potential for discrimination based on the results.DiscussionAs health care systems increasingly implement electronic medical record systems (EMRs) they must carefully consider how to use information from this wide spectrum of genetic tests, with whom to share information, and how to provide decision support for clinicians to properly interpret the information. Although some characteristics of genetic tests overlap with other medical test results, there are reasons to make genetic test results widely available to health care providers and counterbalancing reasons to restrict access to these test results to honor patient preferences, and avoid distracting or confusing clinicians with irrelevant but complex information. Electronic medical records can facilitate and provide reasonable restrictions on access to genetic test results and deliver education and decision support tools to guide appropriate interpretation and use.SummaryThis paper will serve to review some of the key characteristics of genetic tests as they relate to design of access control and decision support of genetic test information in the EMR, emphasizing the clear need for health information technology (HIT) to be part of optimal implementation of genetic medicine, and the importance of understanding key characteristics of genetic tests when designing HIT applications.

We report a 4-year-old girl of Mexican origins with a clinical diagnosis of Dubowitz syndrome who carries a de novo terminal deletion at the 14q32.33 locus identified by array comparative genomic hybridization (aCGH). Dubowitz syndrome is a rare condition characterized by a constellation of features including growth retardation, short stature, microcephaly, micrognathia, eczema, telecanthus, blepharophimosis, ptosis, epicanthal folds, broad nasal bridge, round-tipped nose, mild to moderate developmental delay, and high-pitched hoarse voice. This syndrome is thought to be autosomal recessive; however, the etiology has not been determined. This is the first report of this deletion in association with this phenotype; it is possible that this deletion may be causal for a Dubowitz phenocopy.