The 1.6 Mb 3q29 deletion is associated with developmental and psychiatric phenotypes, including a 40-fold increased risk for schizophrenia. Reduced birth weight and a high prevalence of feeding disorders in patients suggest underlying metabolic dysregulation. We investigated 3q29 deletion-induced metabolic changes using our previously generated heterozygous B6.Del16 +/ Bdh1-Tfrc mouse model. Animals were provided either standard chow (STD) or high-fat diet (HFD). Growth curves were performed on HFD mice to assess weight change ( n = 30–50/group). Indirect calorimetry and untargeted metabolomics were performed on STD and HFD mice to evaluate metabolic phenotypes ( n = 8–14/group). A behavioral battery was performed on STD and HFD mice to assess behavior change after the HFD challenge ( n = 5–13/group). We found that B6.Del16 +/ Bdh1-Tfrc animals preferentially use dietary lipids as an energy source. Untargeted metabolomics of liver tissue showed a strong sex-dependent effect of the 3q29 deletion on fat metabolism. A HFD partially rescued the 3q29 deletion-associated weight deficit in females, but not males. Untargeted metabolomics of liver tissue after HFD revealed persistent fat metabolism alterations in females. The HFD did not affect B6.Del16 +/ Bdh1-Tfrc behavioral phenotypes, suggesting that 3q29 deletion-associated metabolic and behavioral outcomes are uncoupled. Our data suggest that dietary interventions to improve weight phenotypes in 3q29 deletion syndrome patients are unlikely to exacerbate behavioral manifestations. Our study also highlights the importance of assessing sex in metabolic studies and suggests that mechanisms underlying 3q29 deletion-associated metabolic phenotypes are sex-specific.

SUMMARY The 1.6 Mb 3q29 deletion is associated with developmental and psychiatric phenotypes. Reduced birthweight and a high prevalence of feeding disorders in patients suggest underlying metabolic dysregulation. We investigated 3q29 deletion-induced metabolic changes using the B6.Del16 +/ Bdh1-Tfrc mouse model. We found that B6.Del16 +/ Bdh1-Tfrc animals preferentially use dietary lipids as an energy source. Untargeted metabolomics showed a strong sex-dependent effect of the 3q29 deletion on fat metabolism. A high-fat diet (HFD) partially rescued the 3q29 deletion-associated weight deficit in females, but not males. Untargeted metabolomics after HFD revealed persistent fat metabolism alterations in females. The HFD did not affect B6.Del16 +/ Bdh1-Tfrc behavioral phenotypes, suggesting that 3q29 deletion-associated metabolic and behavioral outcomes are uncoupled. Our data indicate a HFD intervention in 3q29 deletion syndrome may improve weight phenotypes without exacerbating behavioral manifestations. Our study also highlights the importance of assessing sex in metabolic studies and suggests mechanisms underlying 3q29 deletion-associated metabolic phenotypes are sex-specific.

Los hemangiomas infantiles son los tumores benignos más frecuentes en la población pediátrica. Cuando afectan al área lumbar y perineal, algunos casos pueden asociarse a alguna malformación subyacente como una disrafia espinal oculta. El manejo de estos hemangiomas carece de consenso. Describimos 3 casos de niños con hemangiomas lumbosacros y perineales con anomalías en la resonancia magnética y revisamos la literatura para valorar qué pruebas y en qué momento se deben realizar para completar el estudio en estos pacientes. Por lo general, se solicita una ecografía lo más precozmente posible, ya que esta técnica no es posible realizarla una vez que los elementos espinales posteriores se han osificado, lo que generalmente ocurre a los 6 meses de edad. La resonancia magnética es la prueba de referencia para diagnosticar una disrafia espinal oculta. De acuerdo con la literatura, la edad media para este examen debe ser alrededor de los 6 meses, cuando la formación de grasa en el filum terminale se ha visto incrementada. En nuestra opinión, se debería realizar una resonancia magnética a los 6 meses de edad en todos los niños con hemangioma lumbar o perineal, independientemente del tamaño de la lesión, la ausencia de síntomas neurológicos o los resultados de la ecografía.Cutaneous hemangiomas are the most frequent benign tumors in children. When they affect the lumbar and perineal area some cases can be associated with an occult spinal dysraphism. The management of these hemangiomas lack consensus. We report 3 cases of children with lumbosacral and perineal hemangiomas with magnetic resonance image abnormalities and we review the literature to find out the type and timing of tests that should be performed to complete the study in these patients. Ultrasound is typically requested as young as possible, as this imaging technique is not possible 11 the posterior spinal elements have ossified. MRI is the gold standard for diagnosing occult spinal dysraphism. According to the literature, the mean age for MRI screening should be around 6 months, when the fat formation in the filum terminale is expanded. In our opinion, an MRI scan should be performed at 6 months of age in every children with lumbar or perineal hemangioma regardless the lesion size, neurological symptoms or the ultrasound results.

The 3q29 deletion confers increased risk for neuropsychiatric phenotypes including intellectual disability, autism spectrum disorder, generalized anxiety disorder, and a >40-fold increased risk for schizophrenia. To investigate consequences of the 3q29 deletion in an experimental system, we used CRISPR/Cas9 technology to introduce a heterozygous deletion into the syntenic interval on C57BL/6 mouse chromosome 16. mRNA abundance for 20 of the 21 genes in the interval was reduced by ~50%, while protein levels were reduced for only a subset of these, suggesting a compensatory mechanism. Mice harboring the deletion manifested behavioral impairments in multiple domains including social interaction, cognitive function, acoustic startle, and amphetamine sensitivity, with some sex-dependent manifestations. In addition, 3q29 deletion mice showed reduced body weight throughout development consistent with the phenotype of 3q29 deletion syndrome patients. Of the genes within the interval, DLG1 has been hypothesized as a contributor to the neuropsychiatric phenotypes. However, we show that Dlg1 +/- mice did not exhibit the behavioral deficits seen in mice harboring the full 3q29 deletion. These data demonstrate the following: the 3q29 deletion mice are a valuable experimental system that can be used to interrogate the biology of 3q29 deletion syndrome; behavioral manifestations of the 3q29 deletion may have sex-dependent effects; and mouse-specific behavior phenotypes associated with the 3q29 deletion are not solely due to haploinsufficiency of Dlg1 .

3q29-deletion syndrome is associated with decreased birth weight and a delayed growth trajectory, as well as intellectual disability, anxiety, autism, and >40-fold increased risk for schizophrenia. To test the hypothesis that haploinsufficiency of the DLG1 gene within the interval is driving these phenotypes, we generated 3q29-deletion (Del16+/Bdh1-Tfrc) mice and compared their phenotypes to Dlg1+/-mice.

Recent studies show that the complex genetic architecture of schizophrenia (SZ) is driven in part by polygenic components, or the cumulative effect of variants of small effect in many genes, as well as rare single‐locus variants with large effect sizes. Here we discuss genetic aberrations known as copy number variants (CNVs), which fall in the latter category and are associated with a high risk for SZ and other neuropsychiatric disorders. We briefly review recurrent CNVs associated with SZ, and then highlight one CNV in particular, a recurrent 1.6‐Mb deletion on chromosome 3q29, which is estimated to confer a 40‐fold increased risk for SZ. Additionally, we describe the use of genetic mouse models, behavioral tools, and patient‐derived induced pluripotent stem cells as a means to study CNVs in the hope of gaining mechanistic insight into their respective disorders. Taken together, the genomic data connecting CNVs with a multitude of human neuropsychiatric disease, our current technical ability to model such chromosomal anomalies in mouse, and the existence of precise behavioral measures of endophenotypes argue that the time is ripe for systematic dissection of the genetic mechanisms underlying such disease. © 2016 Wiley Periodicals, Inc.