Cornelia de Lange Syndrome (CdLS), which is reported to affect about 1 in 10,000 to 30,000 newborns, is a multisystem organ developmental disorder with relatively mild to severe effects. Among others, intellectual disability represents an important feature of this condition.Cornelia de Lange syndrome can result from mutations in at least five genes: NIPBL (nipped-B-like protein), SMC1A (structural maintenance of chromosomes 1A), SMC3 (structural maintenance of chromosomes 3), RAD21 (RAD21 Cohesin Complex Component), and HDAC8 (Histone deacetylase 8). It is believed that mutations in these genes cause CdLS by impairing the function of the cohesin complex (to which all the aforementioned genes contribute to the structure or function), disrupting gene regulation during critical stages of early development.Since intellectual disorder might result from alterations in neural development, in this work, we studied the role of Hdac8 gene in mouse neural stem cells and in vertebrate (D.rerio) brain development by knock-down and chemical inhibition experiments. An underlying features of Hdac8 deficiency is an increased cell death in the developing neural tissues, either in mouse NSCs and in zebrafish embryos.

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Cornelia de Lange syndrome (CdLS) is a rare autosomal-dominant genetic disorder characterised by prenatal and postnatal growth and mental retardation, facial dysmorphism and upper limb abnormalities. Germline mutations of cohesin complex genes SMC1A, SMC3, RAD21 or their regulators NIPBL and HDAC8 have been identified in CdLS as well as somatic mutations in myeloid disorders. We describe the first case of a paediatric patient with CdLS with B-cell precursor Acute Lymphoblastic Leukaemia (ALL). The patient did not show any unusual cytogenetic abnormality, and he was enrolled into the high risk arm of AIEOP-BFM ALL2009 protocol because of slow early response, but 3 years after discontinuation, he experienced an ALL relapse. We identified a heterozygous mutation in exon 46 of NIPBL, causing frameshift and a premature stop codon (RNA-Targeted Next generation Sequencing Analysis). The analysis of the family indicated a de novo origin of this previously not reported deleterious variant. As for somatic cohesin mutations in acute myeloid leukaemia, also this ALL case was not affected by aneuploidy, thus suggesting a major impact of the non-canonical role of NIPBL in gene regulation. A potential biological role of NIPBL in leukaemia has still to be dissected.

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