Learning Disability in RASopathies

Learning disabilities are relatively common conditions in pediatric population. The incidence of learning disability ranges from 1% to 17%, reflecting that learning disability may be not a single clinical entity but a wide distribution of cognitive traits in the population. As reported by the American Association on Intellectual and Developmental Disabilities (AAIDD), among the prenatal learning disability causes, chromosomal disorders, genetic syndromes, and inborn errors of metabolism must be taken into account. In this chapter, we will focus the attention on RASopathies, genetic disorders characterized by germline mutations in the RAS-MAPK pathway whose role is crucial in the regulation of the cell cycle, differentiation, growth, and cell senescence. This group of disorders includes Noonan syndrome, neurofibromatosis type 1, Costello syndrome (CS), Legius syndrome, Noonan syndrome with multiple lentigines, and cardiofaciocutaneous syndrome. Mutations in RAS-MAPK pathways lead to impairments in synaptic plasticity, necessary for normal brain function, especially for learning and memory. Variation across the RAS/MAPK pathway syndromes suggests that different gene mutations affecting this pathway can have markedly different developmental effects

Agenesis of internal carotid artery associated with isolated growth hormone deficiency: A case report and literature review

BACKGROUND: Agenesis of the internal carotid artery (ICA) is a rare congenital abnormality, sporadically reported to be associated with a combined congenital hypopituitarism. Nevertheless, only a few cases have been extensively described, and none of these have been characterized by an isolated growth hormone (GH) deficiency. CASE PRESENTATION: Here, we describe a 17-year old boy referred to our hospital for fatigue, decreased muscle strength and severe headache reported after the cessation of rhGH treatment for a GH deficiency diagnosed at the age of 2 years and 3 months. Magnetic resonance imaging (MRI) showed an adenohypophyseal hypoplasia with a lack of posterior pituitary hyperintensity, whereas MRI angiography indicated the absence of a normal flow void in the left ICA. Endocrinological tests confirmed the GH deficiency (GH peak after growth-hormone-releasing hormone (GHRH) + arginine: 2.42 ng/mL) with a very low IGF-I value (31 ng/mL) and normal function of other pituitary axes. CONCLUSION: To the best of our knowledge this is the first confirmed case of an isolated GH deficiency in a patient with ICA agenesis. The presence of an isolated pituitary deficit is unlike to be considered only as an effect of hemodynamic mechanism, suggesting a role for genetic factor(s) as a common cause of these two rare birth defects. Further studies could clarify this issue and the underlying mechanisms to better understand the etiopathogenetic characteristics of this disorder. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12902-015-0037-y) contains supplementary material, which is available to authorized users

Estudio clínico y molecular en una familia con displasia ectodérmica hipohidrótica autosómica dominante

Hypohidrotic ectodermal dysplasia (HED) is a rare disease characterized by deficiency in development of structure derived from the ectoderm and is caused by mutations in the genes EDA, EDAR, or EDARADD. Phenotypes caused by mutations in these three may exhibit similar clinical features, explained by a common signaling pathway. Mutations in EDA gene cause X linked HED, which is the most common form. Mutations in EDAR and EDARADD genes cause autosomal dominant and recessive form of HED. The most striking clinical findings in HED are hypodontia, hypotrichosis and hypohidrosis that can lead to episodes of hyperthermia. We report on clinical findings in a child with HED with autosomal dominant inheritance pattern with a heterozygous mutation c.1072C>T (p.Arg358X) in the EDAR gene. A review of the literature with regard to other cases presenting the same mutation has been carried out and discussed

Genetic deletion of mGlu2 metabotropic glutamate receptors improves the short-term outcome of cerebral transient focal ischemia

Abstract We have recently shown that pharmacological blockade of mGlu2 metabotropic glutamate receptors protects vulnerable neurons in the 4-vessel occlusion model of transient global ischemia, whereas receptor activation amplifies neuronal death. This raised the possibility that endogenous activation of mGlu2 receptors contributes to the pathophysiology of ischemic neuronal damage. Here, we examined this possibility using two models of transient focal ischemia: (i) the monofilament model of middle cerebral artery occlusion (MCAO) in mice, and (ii) the model based on intracerebral infusion of endothelin-1 (Et-1) in rats. Following transient MCAO, mGlu2 receptor knockout mice showed a significant reduction in infarct volume and an improved short-term behavioural outcome, as assessed by a neurological disability scale and the “grip test”. Following Et-1 infusion, Grm2 gene mutated Hannover Wistar rats lacking mGlu2 receptors did not show changes in the overall infarct volume as compared to their wild-type counterparts, although they showed a reduced infarct area in the agranular insular cortex. Interestingly, however, mGlu2 receptor-deficient rats performed better than wild-type rats in the adhesive tape test, in which these rats did not show the laterality preference typically observed after focal ischemia. These findings support the hypothesis that activation of mGlu2 receptors is detrimental in the post-ischemic phase, and support the use of mGlu2 receptor antagonists in the experimental treatment of brain ischemia

La Sindrome di Di George: revisione aggiornata e contributo clinico

La sinfrome di Di George è una patologia causata da un disturbo dell'embriogenesi della terza e quarta tasca faringea e delle creste neurali, riferibile a microdelezioni del braccio lungo del cromosoma 22. Il quadro fenotipico tipico è caratterizzato da difetti cardiaci di tipo tronco-conale, dismorfismi facciali, anomalie del palato, ipocalcemia, deficit immunitari, difficoltà del linguaggio e dell'apprendimento. Possono essere presenti anche alterazioni del tratto genito-orinario, disturbo gastrointestinali, disturbi psichiatrici. Le caratteristiche cliniche di questi pazienti sono molto variabili per cui la diagnosi di certezza si ottiene con la dimostrazione delle microdelezioni mediante tecniche di ibridazione in situ (fish). Per questo nostro lavoro di tesi abbiamo seguito un gruppo di pazienti giunti presso il dipartimento di pediatria di Pisa. I dati raccolti sono stati analizzati alla luce delle più recenti acquisizioni in ambito diagnostico e terapeutico e degli studi riportati in letteratura

A SOX3 (Xq26.3-27.3) duplication in a boy with growth hormone deficiency, ocular dyspraxia, and intellectual disability: A long-term follow-up and literature review

OBJECTIVE: SOX3 is located on the long arm of the X chromosome (Xq27.1) and both the under- and over-expression of this gene have been reported in cases of hypopituitarism with or without intellectual disabilities. Nevertheless, only a few cases have as yet been extensively described. DESIGN: A 3-year 11 month-old male was brought in for growth failure (height -2.4 SDS). The patient was born at term of a second uneventful pregnancy by caesarean section for podalic presentation: the birth weight (0.1 SDS), length (0.4 SDS), and head circumference (-0.3 SDS) were normal. Neurodevelopmental delays and ocular motor dyspraxia had been noted since 6 months of age. The endocrinological evaluation showed a very low IGF-I concentration (44 μg/L). The thyroid hormone level was normal and coeliac disease markers were negative. Bone age was considerably delayed. Target height was normal (0.5 SDS). RESULTS: Growth hormone stimulation tests were compatible with a classic GHD, while a brain MRI disclosed a pituitary hypoplasia with ectopic neurohypophysis. rhGH treatment was then begun and the auxological follow-up showed a good response. At the age of 9 yrs, the height was 0.3 SDS, the weight was 0.1 SDS, and the pubertal evaluation was PH1 AH1 T2 ml bilaterally. Due to the presence of neuromotor delays and MRI abnormalities, a genetic evaluation was conducted and an array-CGH of the patient’s DNA discovered an Xq26.3-27.3 duplication comprising the SOX3 gene. CONCLUSIONS: SOX3 involvement should be considered in a male with short stature due to GH deficiency associated with intellectual disability

Genetic counseling during COVID‐19 pandemic: Tuscany experience

Abstract Background COVID‐19 outbreak prompted health centres to reorganize their clinical and surgical activity. In this paper, we show how medical genetics department's activity, in our tertiary pediatric hospital, has changed due to pandemic. Methods We stratified all our scheduled visits, from March 9th through April 30th, and assessed case‐by‐case which genetic consultations should be maintained as face‐to‐face visit, or postponed/switched to telemedicine. Results Out of 288 scheduled appointments, 60 were prenatal consultations and 228 were postnatal visits. We performed most of prenatal consultations as face‐to‐face visits, as women would have been present in the hospital to perform other procedures in addition to our consult. As for postnatal care, we suspended all outpatient first visits and opted for telemedicine for selected follow‐up consultations: interestingly, 75% of our patients’ parents revealed that they would have cancelled the appointment themselves for the fear to contract an infection. Conclusions Spread of COVID‐19 in Italy forced us to change our working habits. Given the necessity to optimize healthcare resources and minimize the risk of in‐hospital infections, we experienced the benefits of telegenetics. Current pandemic made us familiar with telemedicine, laying the foundations for its application to deal with the increasing number of requests in clinical genetics