Cantú syndrome with coexisting familial pituitary adenoma

Context: Pseudoacromegaly describes conditions with an acromegaly related physical appearance without abnormalities in the growth hormone (GH) axis. Acromegaloid facies, together with hypertrichosis, are typical manifestations of Cantú syndrome. Case description: We present a three-generation family with 5 affected members, with marked acromegaloid facies and prominent hypertrichosis, due to a novel missense variant in the ABCC9 gene. The proband, a 2-year-old girl, was referred due to marked hypertrichosis, noticed soon after birth, associated with coarsening of her facial appearance. Her endocrine assessment, including of the GH axis, was normal. The proband's father, paternal aunt, and half-sibling were referred to the Endocrine department for exclusion of acromegaly. Although the GH axis was normal in all, two subjects had clinically non-functioning pituitary macroadenomas, a feature which has not previously been associated with Cantú syndrome. Conclusions: Activating mutations in the ABCC9 and, less commonly, KCNJ8 genes—representing the two subunits of the ATP-sensitive potassium channel—have been linked with Cantú syndrome. Interestingly, minoxidil, a well-known ATP-sensitive potassium channel agonist, can cause a similar phenotype. There is no clear explanation why activating this channel would lead to acromegaloid features or hypertrichosis. This report raises awareness for this complex condition, especially for adult or pediatric endocrinologists who might see these patients referred for evaluation of acromegaloid features or hirsutism. The link between Cantú syndrome and pituitary adenomas is currently unclear

Glial Tumor Necrosis Factor Alpha (TNFα) Generates Metaplastic Inhibition of Spinal Learning

Injury-induced overexpression of tumor necrosis factor alpha (TNFα) in the spinal cord can induce chronic neuroinflammation and excitotoxicity that ultimately undermines functional recovery. Here we investigate how TNFα might also act to upset spinal function by modulating spinal plasticity. Using a model of instrumental learning in the injured spinal cord, we have previously shown that peripheral intermittent stimulation can produce a plastic change in spinal plasticity (metaplasticity), resulting in the prolonged inhibition of spinal learning. We hypothesized that spinal metaplasticity may be mediated by TNFα. We found that intermittent stimulation increased protein levels in the spinal cord. Using intrathecal pharmacological manipulations, we showed TNFα to be both necessary and sufficient for the long-term inhibition of a spinal instrumental learning task. These effects were found to be dependent on glial production of TNFα and involved downstream alterations in calcium-permeable AMPA receptors. These findings suggest a crucial role for glial TNFα in undermining spinal learning, and demonstrate the therapeutic potential of inhibiting TNFα activity to rescue and restore adaptive spinal plasticity to the injured spinal cord. TNFα modulation represents a novel therapeutic target for improving rehabilitation after spinal cord injury

A synonymous splicing mutation in the SF3B4 gene segregates in a family with highly variable Nager syndrome.

Nager syndrome is a rare preaxial acrofacial dysostosis that is caused by heterozygous loss-of-function variants in SF3B4. This gene encodes for a protein required for the assembly of spliceosomal complexes, being a master gene for splicing regulation. The main clinical features of Nager syndrome include facial-mandibular and preaxial limb malformations, with normal cognitive functioning. Most Nager patients are sporadic, but few familial cases with a highly variable phenotype have been reported. In this work, we report a novel synonymous variant within exon 3 of the SF3B4 gene in a family with three members affected by Nager syndrome. No pathogenic variants have been detected in other 24 genes associated with syndromes characterized by mandibulo-facial anomalies. The pathogenicity of the mutation was demonstrated through a hybrid minigene assay, which confirmed an aberrant splicing with the creation of a cryptic splice site, and showed that this allele is hypomorphic. Our findings emphasize the importance to perform functional analyses to assess the possible consequences of synonymous variants and confirmed that hybrid minigenes represent an effective tool to evaluate the effects of variants on splicing, particularly when RNA is not available

Loss-of-function variants of SETD5 cause intellectual disability and the core phenotype of microdeletion 3p25.3 syndrome.

Intellectual disability (ID) has an estimated prevalence of 2-3%. Due to its extreme heterogeneity, the genetic basis of ID remains elusive in many cases. Recently, whole exome sequencing (WES) studies revealed that a large proportion of sporadic cases are caused by de novo gene variants. To identify further genes involved in ID, we performed WES in 250 patients with unexplained ID and their unaffected parents and included exomes of 51 previously sequenced child-parents trios in the analysis. Exome analysis revealed de novo intragenic variants in SET domain-containing 5 (SETD5) in two patients. One patient carried a nonsense variant, and the other an 81 bp deletion located across a splice-donor site. Chromosomal microarray diagnostics further identified four de novo non-recurrent microdeletions encompassing SETD5. CRISPR/Cas9 mutation modelling of the two intragenic variants demonstrated nonsense-mediated decay of the resulting transcripts, pointing to a loss-of-function (LoF) and haploinsufficiency as the common disease-causing mechanism of intragenic SETD5 sequence variants and SETD5-containing microdeletions. In silico domain prediction of SETD5, a predicted SET domain-containing histone methyltransferase (HMT), substantiated the presence of a SET domain and identified a novel putative PHD domain, strengthening a functional link to well-known histone-modifying ID genes. All six patients presented with ID and certain facial dysmorphisms, suggesting that SETD5 sequence variants contribute substantially to the microdeletion 3p25.3 phenotype. The present report of two SETD5 LoF variants in 301 patients demonstrates a prevalence of 0.7% and thus SETD5 variants as a relatively frequent cause of ID