Objective measures of sleep disturbances in children with Potocki-Lupski syndrome

Derivation of induced pluripotent stem cells from one child suffering Potocki-Lupski syndrome

Potocki-Lupski syndrome (PTLS; MIM 610883) is a neurodevelopmental disorder associated with a 3.7 Mb copy number variant (CNV) duplication, locating in chromosome 17p11.2. (Soler-Alfonso et al., 2011). Here, a human induced pluripotent stem cell (iPSC) line was derived from the peripheral blood mononuclear cells of a 5-year-old child suffering Potocki-Lupski syndrome. The generated iPSCs were integration-free, had the 17p11.2 3.7 Mb CNV duplication with no additional genomic alterations, a stable karyotype, expressed pluripotency stem cell markers and could differentiate towards the three germ layers in vitro. Patient's derived iPSCs are a valuable resource for in vitro modeling of 17p11.2 microduplication induced Potocki-Lupski syndrome.

Dosage-sensitive genes in autism spectrum disorders: From neurobiology to therapy

Autism spectrum disorders (ASDs) are a group of heterogenous neurodevelopmental disorders affecting 1 in 59 children. Syndromic ASDs are commonly associated with chromosomal rearrangements or dosage imbalance involving a single gene. Many of these genes are dosage-sensitive and regulate transcription, protein homeostasis, and synaptic function in the brain. Despite vastly different molecular perturbations, syndromic ASDs share core symptoms including social dysfunction and repetitive behavior. However, each ASD subtype has a unique pathogenic mechanism and combination of comorbidities that require individual attention. We have learned a great deal about how these dosage-sensitive genes control brain development and behaviors from genetically-engineered mice. Here we describe the clinical features of eight monogenic neurodevelopmental disorders caused by dosage imbalance of four genes, as well as recent advances in using genetic mouse models to understand their pathogenic mechanisms and develop intervention strategies. We propose that applying newly developed quantitative molecular and neuroscience technologies will advance our understanding of the unique neurobiology of each disorder and enable the development of personalized therapy.

Neurological phenotype of Potocki-Lupski syndrome

Potocki-Lupski syndrome is a condition mainly characterized by infantile hypotonia, developmental delay/intellectual disability (DD/ID), and congenital anomalies, caused by duplications of the 17p11.2 region, encompassing RAI1 gene. Its clinical presentation is extremely variable, especially for what concerns the cognitive level and the behavioral phenotype. Such aspects, as well as the dysmorphic/malformative ones, have been covered by previous studies; otherwise neurological features have never been systematically described. In order to delineate the neurological phenotype of Potocki-Lupski Syndrome, we collect an 8-patients cohort. Developmental milestones are delayed and a mild to moderate cognitive impairment is present in all patients, variably associated with features of autism spectrum disorder, behavioral disturb, and sleep disturb. Hypotonia appears a less frequent finding than what previously reported, while motor clumsiness/coordination impairment is frequent. EGG registration demonstrated a common pattern with excess of diffuse rhythmic activity in sleep phases or while the patient is falling asleep. Brain MRI did not reveal common anomalies, although unspecific white matter changes may be present. We discuss such findings and compare them to literature data, offering an overview on the neurological and cognitive-behavioral presentation of the syndrome.