Immunological Aspects of Kabuki Syndrome: A Retrospective Multicenter Study of the Italian Primary Immunodeficiency Network (IPINet)

Kabuki Syndrome (KS) is a multisystemic genetic disorder. A portion of patients has immunological manifestations characterized by increased susceptibility to infections and autoimmunity. Aiming to describe the clinical and laboratory immunological aspects of KS, we conducted a retrospective multicenter observational study on patients with KS treated in centers affiliated to the Italian Primary Immunodeficiency Network.Thirty-nine patients were enrolled, with a median age at evaluation of 10 years (range: 3 m-21y). All individuals had organ malformations of variable severity. Congenital heart defect (CHD) was present in 19/39 patients (49%) and required surgical correction in 9/39 (23%), with associated thymectomy in 7/39 (18%). Autoimmune cytopenia occurred in 6/39 patients (15%) and was significantly correlated with thymectomy (p < 0.002), but not CHD. Individuals with cytopenia treated with mycophenolate as long-term immunomodulatory treatment (n = 4) showed complete response. Increased susceptibility to infections was observed in 22/32 patients (69%). IgG, IgA, and IgM were low in 13/29 (45%), 13/30 (43%) and 4/29 (14%) patients, respectively. Immunoglobulin substitution was required in three patients. Lymphocyte subsets were normal in all patients except for reduced naïve T-cells in 3/15 patients (20%) and reduced memory switched B-cells in 3/17 patients (18%). Elevated CD3 + TCRαβ + CD4-CD8-T-cells were present in 5/17 individuals (23%) and were correlated with hematological and overall autoimmunity (p < 0.05).In conclusion, immunological manifestations of KS in our cohort include susceptibility to infections, antibody deficiency, and autoimmunity. Autoimmune cytopenia is correlated with thymectomy and elevated CD3 + TCRαβ + CD4-CD8-T-cells, and benefits from treatment with mycophenolate.

Endocrine involvement in hepatic glycogen storage diseases: pathophysiology and implications for care

Hepatic glycogen storage diseases constitute a group of disorders due to defects in the enzymes and transporters involved in glycogen breakdown and synthesis in the liver. Although hypoglycemia and hepatomegaly are the primary manifestations of (most of) hepatic GSDs, involvement of the endocrine system has been reported at multiple levels in individuals with hepatic GSDs. While some endocrine abnormalities (e.g., hypothalamic‑pituitary axis dysfunction in GSD I) can be direct consequence of the genetic defect itself, others (e.g., osteopenia in GSD Ib, insulin-resistance in GSD I and GSD III) may be triggered by the (dietary/medical) treatment. Being aware of the endocrine abnormalities occurring in hepatic GSDs is essential (1) to provide optimized medical care to this group of individuals and (2) to drive research aiming at understanding the disease pathophysiology. In this review, a thorough description of the endocrine manifestations in individuals with hepatic GSDs is presented, including pathophysiological and clinical implications.

The role of unidentified bright objects in the neurocognitive profile of neurofibromatosis type 1 children: a volumetric MRI analysis

PURPOSE

Cognitive impairment is described in 80% of Neurofibromatosis type 1 (NF1) patients. Brain focal areas of T2w increased signal intensity on MRI, the so-called Unidentified Bright Objects (UBOs) have been hypothesized to be related to cognitive dysfunction, although conflicting results are available in literature. Here, we investigated the possible relation between UBOs' volume, cognitive impairment, and language disability in NF1 patients.

MATERIAL AND METHODS

In this retrospective study, clinical and MRI data of 21 NF1 patients (M/F = 12/9; mean age 10.1 ± 4.5) were evaluated. Brain intellectual functioning and language abilities were assessed with specific scales, while the analyzed MRI sequences included axial 2D-T2-weighted and FLAIR sequences. These images were used independently for UBOs segmentation with a semiautomatic approach and obtained volumes were normalized for biparietal diameters to take into account for brain volume. Possible differences in terms of normalized UBOs volumes were probed between cognitively affected and preserved patients, as well as between subjects with or without language impairment.

RESULTS

Patients cognitively affected were not different in terms of UBOs volume compared to those preserved (p = 0.35 and p = 0.30, for T2-weighted and FLAIR images, respectively). Similarly, no differences were found between patients with and without language impairment (p = 0.47 and p = 0.40, for the two sequences).

CONCLUSIONS

The relation between UBOs and cognition in children with NF1 has been already investigated in literature, although leading to conflicting results. Our study expands the current knowledge, showing a lack of correlation between UBOs volume and both cognitive impairment and language disability in NF1 patients.

Clinical profiling of MRD48 and functional characterization of two novel pathogenic RAC1 variants

RAC1 is a member of the Rac/Rho GTPase subfamily within the RAS superfamily of small GTP-binding proteins, comprising 3 paralogs playing a critical role in actin cytoskeleton remodeling, cell migration, proliferation and differentiation. De novo missense variants in RAC1 are associated with a rare neurodevelopmental disorder (MRD48) characterized by DD/ID and brain abnormalities coupled with a wide range of additional features. Structural and functional studies have documented either a dominant negative or constitutively active behavior for a subset of mutations. Here, we describe two individuals with previously unreported de novo missense RAC1 variants. We functionally demonstrate their pathogenicity proving a gain-of-function (GoF) effect for both. By reviewing the clinical features of these two individuals and the previously published MRD48 subjects, we further delineate the clinical profile of the disorder, confirming its phenotypic variability. Moreover, we compare the main features of MRD48 with the neurodevelopmental disease caused by GoF variants in the paralog RAC3, highlighting similarities and differences. Finally, we review all previously reported variants in RAC proteins and in the closely related CDC42, providing an updated overview of the spectrum and hotspots of pathogenic variants affecting these functionally related GTPases.

Mitochondrial reprogramming in peripheral blood mononuclear cells of patients with glycogen storage disease type Ia

BACKGROUND

Glycogen storage disease type Ia (GSDIa) is an inborn metabolic disorder caused by the deficiency of glucose-6-phospatase-α (G6Pase-α) leading to mitochondrial dysfunction. It remains unclear whether mitochondrial dysfunction is present in patients' peripheral blood mononuclear cells (PBMC) and whether dietary treatment can play a role. The aim of this study was to investigate mitochondrial function in PBMC of GSDIa patients.

METHODS

Ten GSDIa patients and 10 age-, sex- and fasting-time matched controls were enrolled. Expression of genes involved in mitochondrial function and activity of key fatty acid oxidation (FAO) and Krebs cycle proteins were assessed in PBMC. Targeted metabolomics and assessment of metabolic control markers were also performed.

RESULTS

Adult GSDIa patients showed increased CPT1A, SDHB, TFAM, mTOR expression (p < 0.05) and increased VLCAD, CPT2 and citrate synthase activity in PBMC (p < 0.05). VLCAD activity directly correlated with WC (p < 0.01), BMI (p < 0.05), serum malonycarnitine levels (p < 0.05). CPT2 activity directly correlated with BMI (p < 0.05).

CONCLUSION

Mitochondrial reprogramming is detectable in PBMC of GSDIa patients. This feature may develop as an adaptation to the liver enzyme defect and may be triggered by dietary (over)treatment in the frame of G6Pase-α deficiency. PBMC can represent an adequate mean to assess (diet-induced) metabolic disturbances in GSDIa.

FOXI3 pathogenic variants cause one form of craniofacial microsomia

Craniofacial microsomia (CFM; also known as Goldenhar syndrome), is a craniofacial developmental disorder of variable expressivity and severity with a recognizable set of abnormalities. These birth defects are associated with structures derived from the first and second pharyngeal arches, can occur unilaterally and include ear dysplasia, microtia, preauricular tags and pits, facial asymmetry and other malformations. The inheritance pattern is controversial, and the molecular etiology of this syndrome is largely unknown. A total of 670 patients belonging to unrelated pedigrees with European and Chinese ancestry with CFM, are investigated. We identify 18 likely pathogenic variants in 21 probands (3.1%) in FOXI3. Biochemical experiments on transcriptional activity and subcellular localization of the likely pathogenic FOXI3 variants, and knock-in mouse studies strongly support the involvement of FOXI3 in CFM. Our findings indicate autosomal dominant inheritance with reduced penetrance, and/or autosomal recessive inheritance. The phenotypic expression of the FOXI3 variants is variable. The penetrance of the likely pathogenic variants in the seemingly dominant form is reduced, since a considerable number of such variants in affected individuals were inherited from non-affected parents. Here we provide suggestive evidence that common variation in the FOXI3 allele in trans with the pathogenic variant could modify the phenotypic severity and accounts for the incomplete penetrance.

Genotypes and phenotypes heterogeneity in PIK3CA-related overgrowth spectrum and overlapping conditions: 150 novel patients and systematic review of 1007 patients with PIK3CA pathogenetic variants

BACKGROUND

Postzygotic activating PIK3CA variants cause several phenotypes within the PIK3CA-related overgrowth spectrum (PROS). Variant strength, mosaicism level, specific tissue involvement and overlapping disorders are responsible for disease heterogeneity. We explored these factors in 150 novel patients and in an expanded cohort of 1007 PIK3CA-mutated patients, analysing our new data with previous literature to give a comprehensive picture.

METHODS

We performed ultradeep targeted next-generation sequencing (NGS) on DNA from skin biopsy, buccal swab or blood using a panel including phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin pathway genes and GNAQ, GNA11, RASA1 and TEK. Additionally, 914 patients previously reported were systematically reviewed.

RESULTS

93 of our 150 patients had PIK3CA pathogenetic variants. The merged PROS cohort showed that PIK3CA variants span thorough all gene domains, some were exclusively associated with specific PROS phenotypes: weakly activating variants were associated with central nervous system (CNS) involvement, and strongly activating variants with extra-CNS phenotypes. Among the 57 with a wild-type PIK3CA allele, 11 patients with overgrowth and vascular malformations overlapping PROS had variants in GNAQ, GNA11, RASA1 or TEK.

CONCLUSION

We confirm that (1) molecular diagnostic yield increases when multiple tissues are tested and by enriching NGS panels with genes of overlapping 'vascular' phenotypes; (2) strongly activating PIK3CA variants are found in affected tissue, rarely in blood: conversely, weakly activating mutations more common in blood; (3) weakly activating variants correlate with CNS involvement, strong variants are more common in cases without; (4) patients with vascular malformations overlapping those of PROS can harbour variants in genes other than PIK3CA.

Severe impact of late diagnosis of congenital adrenal hyperplasia on gender identity, sexual orientation and function: case report and review of the literature

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD) represents the most frequent form of CAH and of 46, XX disorder of sex development in female newborns. In the majority of cases, particularly in developed countries, female patients suffering from the classic forms of CAH reach the diagnosis at birth or in the early childhood, allowing a prompt treatment with a correct gender assignment. The current manuscript describes an unusual case of an Italian 46-year-old woman, homeborn in the 60s, receiving an extraordinarily late diagnosis of simple virilising classic form of CAH due to 21-OHD, determining a relevant impairment of both physical and psychosexual development. The patient presented primary amenorrhea, height under target, overweight with visceral adiposity, hypercholesterolemia and insulin resistance, hirsutism with a typical male-pattern hair growth, external genital ambiguity, and a severe impairment in the entire series of psychological dimensions, particularly severe depressive symptoms, together with gender dysphoria relative to the female gender assigned at birth, cross-gender behaviours, and body image discomfort, which were associated with homosexual orientation, and sexual dysfunction. Following diagnosis and glucocorticoid (GC) replacement therapy, the hyperandrogenism control and familial and socio-cultural factors changes, particularly, living alone and the interruption of social isolation, were accompanied by menarche appearance, improvement in hirsutism and metabolic profile, and a resolution in all psychological dimensions, depressive symptoms, and gender dysphoria. The patient began to perceive homosexual orientation without discomfort, and ameliorating sexual function. Few cases of female patients with CAH due to 21-OHD receiving an extremely delayed diagnosis have been published. However, to the best of our knowledge, this is the first case including a complete psychosexual assessment at diagnosis with a detailed re-evaluation after 5 years of disease treatment.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) antigen detection in the Emergency Department: data from a pediatric cohort during the fourth COVID-19 wave in Italy

BACKGROUND

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic has been challenging health care systems and made it necessary to use rapid and cost-effective testing methods, particularly in Emergency Department (ED) settings. Rapid Antigen Diagnostic Tests (RADTs) are a valid alternative to the gold standard RT-PCR, even in pediatric populations. This retrospective observational study has been conducted on a pediatric cohort afferent to the ED of the San Giovanni di Dio and Ruggi d'Aragona University Hospital in Salerno, tested at Point of Care with RADT Panbio® (Abbott), from September 1^st, 2021 to February 28^th, 2022, analyzing the positivity rate and clinical features of the cohort, also in reference to the rise of positive cases observed in the aforementioned period, and to the introduction in Italy of SARS-CoV-2 vaccination for children and teens on December 16^th, 2021.

METHODS

Data regarding access to the pediatric ED were extracted from the hospital's electronic database system. Parallel to this, we conducted a narrative literature search using PubMed database focusing on the use of RADT in pediatric ED and compared our data with the national pandemic trend.

RESULTS

During the observation period, 1890 patients were tested for the presence of SARS-CoV-2 with RADT and the 2.7% of children resulted positive, with a peak in January 2022. The main symptoms in positive patients were: fever (n = 34; 66.7%), cough (n = 11; 21.5%), headache (n = 4; 7.8%), chest pain (n = 2; 3.9%) and abdominal pain (n = 1; 2%). Patients were divided into three different age groups (A, B, C) basing on the different access timing to vaccination; no statistically significant difference was detected in the distribution of positivity in these three groups (p > 0.05). Number of positive children in group A was greater in the post-vaccine group. Our data are concordant with the national trend of the pandemic showing a fourth wave peak in January 2022.

CONCLUSION

The use of RADT as a first point-of-care screening may be helpful, time-saving and cost-sparing. Our study shows that, during the observation period, most children admitted to the ED for fever, actually tested positive for SARS-CoV-2 with a statistically greater difference than negative children. Instead, number of patients admitted for cough was statistically higher among negative than positive ones, probably due to the circulation of other respiratory viruses in children.

Clinical and molecular characterization of patients affected by Beckwith-Wiedemann spectrum conceived through assisted reproduction techniques

The prevalence of Beckwith–Wiedemann spectrum (BWSp) is tenfold increased in children conceived through assisted reproductive techniques (ART). More than 90% of ART‐BWSp patients reported so far display imprinting center 2 loss‐of‐methylations (IC2‐LoM), versus 50% of naturally conceived BWSp patients. We describe a cohort of 74 ART‐BWSp patients comparing their features with a cohort of naturally conceived BWSp patients, with the ART‐BWSp patients previously described in literature, and with the general population of children born from ART. We found that the distribution of UPD(11)pat was not significantly different in ART and naturally conceived patients. We observed 68.9% of IC2‐LoM and 16.2% of mosaic UPD(11)pat in our ART cohort, that strongly differ from the figure reported in other cohorts so far. Since UPD(11)pat likely results from post‐fertilization recombination events, our findings allows to hypothesize that more complex molecular mechanisms, besides methylation disturbances, may underlie BWSp increased risk in ART pregnancies. Moreover, comparing the clinical features of ART and non‐ART BWSp patients, we found that ART‐BWSp patients might have a milder phenotype. Finally, our data show a progressive increase in the prevalence of BWSp over time, paralleling that of ART usage in the last decades.

Clinical heterogeneity of Kabuki syndrome in a cohort of Italian patients and review of the literature

Kabuki syndrome (KS) is a well-recognized disorder characterized by postnatal growth deficiency, dysmorphic facial features, skeletal anomalies, and intellectual disability. The syndrome is caused by KMT2D gene mutations or less frequently KDM6A gene mutations or deletions. We report a systematic evaluation of KS patients from Campania region of Italy; data were also compared with literature ones. We collected data of 15 subjects (8 males and 7 females with age range 10-26 years; mean age 16.9 years) with confirmed diagnosis of KS, representing the entire cohort of patients from Campania Region. Each patient performed biochemical testing and instrumental investigation. Neuro-intellectual development, cranio-facial dysmorphisms, and multisystem involvement data were collected retrospectively. For each category, type of defects and frequency of the anomalies were analyzed. Our observation shows that KS patients from Campania region have some particular and previously underscored, neurological and immunological findings. We found high prevalence of EEG's abnormalities (43%) and MRI brain abnormalities (60%). Microcephaly resulted more common in our series (33%), if compared with major cohorts described in literature. Biochemical features of immunodeficiency and autoimmune diseases including thyroid autoimmunity, polyserositis, and vitiligo were observed with high prevalence (54.5%). Low immunoglobulins levels were a frequent finding. Lymphocyte class investigation showed significantly reduced CD8 levels in one patient.Conclusions: These data confirm great heterogeneity of clinical manifestations in KS and suggest to introduce further clinical diagnostic criteria in order to perform a correct and precocious diagnosis. What is Known • Kabuki syndrome is characterized by growth deficiency, dysmorphic facial features, skeletal anomalies, and intellectual disability • Immune dysfunction is a common finding but autoimmune diseases are rarely seen • Neurological features are common What is New • Some particular facial features could help gestalt diagnosis (hypertelorism, broad nasal bridge, micrognathia, tooth agenesis, cutaneous haemangiomas and strabismus) • Higher prevalence of autoimmune disorders than previously reported • Particular neurological features are present in this cohort (EEG and MRI brain abnormalities).

Endocrine system involvement in patients with RASopathies: A case series

BACKGROUND AND OBJECTIVES

Endocrine complications have been described in patients affected by RASopathies but no systematic assessment has been reported. In this study, we investigate the prevalence of endocrine disorders in a consecutive unselected cohort of patients with RASopathies.

STUDY DESIGN

72 patients with a genetically confirmed RASopathy (Noonan syndrome [NS], N=53; 29 LEOPARD syndrome [LS], N=2; cardiofaciocutaneous syndrome [CFCS], N=14; subjects showing co-occurring pathogenic variants in PTPN11 and NF1, N=3) and an age- and sex-matched healthy controls were included in the study. Endocrine system involvement was investigated by assessing the thyroid function, pubertal development, auxological parameters, adrenal function and bone metabolism.

RESULTS

Short stature was detected in 40% and 64% of the NS and CFCS subcohorts, respectively. Patients showed lower Z-scores at DXA than controls (p<0.05) when considering the entire case load and both NS and CFCS groups. Vitamin D and Calcitonin levels were significantly lower (p< 0.01), Parathormone levels significantly higher (p<0.05) in patients compared to the control group (p<0.05). Patients with lower BMD showed reduced physical activity and joint pain. Finally, anti-TPO antibody levels were significantly higher in patients than in controls when considering the entire case load and both NS and CFCS groups.

CONCLUSIONS

The collected data demonstrate a high prevalence of thyroid autoimmunity, confirming an increased risk to develop autoimmune disorders both in NS and CFCS. Reduced BMD, probably associated to reduced physical activity and inflammatory cytokines, also occurs. These findings are expected to have implications for the follow-up and prevention of osteopenia/osteoporosis in both NS and CFCS.

Exosomal MicroRNAs as Potential Biomarkers of Hepatic Injury and Kidney Disease in Glycogen Storage Disease Type Ia Patients

Glycogen storage disease type Ia (GSDIa) is an inherited metabolic disorder caused by mutations in the enzyme glucose-6-phosphatase-α (G6Pase-α). Affected individuals develop renal and liver complications, including the development of hepatocellular adenoma/carcinoma and kidney failure. The purpose of this study was to identify potential biomarkers of the evolution of the disease in GSDIa patients. To this end, we analyzed the expression of exosomal microRNAs (Exo-miRs) in the plasma exosomes of 45 patients aged 6 to 63 years. Plasma from age-matched normal individuals were used as controls. We found that the altered expression of several Exo-miRs correlates with the pathologic state of the patients and might help to monitor the progression of the disease and the development of late GSDIa-associated complications.

RASopathies and hemostatic abnormalities: key role of platelet dysfunction

Background

Bleeding anomalies have been reported in patients affected by Noonan syndrome. No study has been performed in patients with molecularly confirmed RASopathy. We aimed to characterize the frequency and types of bleeding disorders in patients with RASopathies and evaluate any significant association with laboratory findings.

Patients and methods

Forty-nine individuals (PTPN11, n = 27; SOS1, n = 7; RIT1, n = 3; SPRED1, n = 1; LZTR1, N = 3; RAF1, n = 2; BRAF, n = 4; MEK1, n = 1; MEK2, n = 1), and 49 age- and sex-matched controls were enrolled. The “Paediatric Bleeding Questionnaire Scoring Key” was administered to patients and families. Laboratory screening tests including clotting factors dosing, platelet count, Prothrombin Time and Partial Thromboplastin Time, were employed both in patients and controls to characterize the bleeding diathesis. A subgroup of 29/49 patients and 29/49 controls was also tested for platelet function.

Results

Regardless of the gene involved, pathological paediatric bleeding scores were recorded in 14/49 (28.5%) patients. Indeed, 7 were mutated in PTPN11, 3 in SOS1, 2 in RIT1, 1 in BRAF, and 1 in MEK1. Compared to patients with normal bleeding scores, those with pathologic bleeding score showed higher prevalence of splenomegaly (p = 0.006), prolonged aPTT (p = 0.04), lower levels of coagulation factor V (FV, p = 0.001), FVII (p = 0.003), FX (p = 0.0008) and FXIII (p = 0.002), higher vWAg (p = 0.04), and lower platelet sensitivity to Ristocetin (p = 0.001), arachidonic acid (AA) (p = 0.009) and collagen (p = 0.01). The presence of hematomas inversely correlated with factor V (p = 0.002), factor VII (p = 0.003), factor X (p = 0.002) and factor XIII (p = 0.004) levels, and directly correlated with platelet response to collagen (p = 0.02) and AA (p = 0.01). The presence of splenomegaly directly correlated with the presence of hematoma (p = 0.006), platelet response to Ristocetin (p = 0.04) and AA (p = 0.04), and inversely correlated with factor V levels (p = 0.03).

Conclusions

Patients with RASopathies and a bleeding tendency exhibit multiple laboratory abnormalities, including platelet-related disorders. Splenomegaly is frequently detected and might be a suggestive sign for qualitative platelet dysfunction. A comprehensive clinical assessment should be carried out at diagnosis, during the follow-up and before any surgical procedures. Since there is currently no consensus on management of bleeding complications, it is important that physicians closely monitor these patients.

DNA methylation episignature testing improves molecular diagnosis of Mendelian chromatinopathies

PURPOSE

Chromatinopathies include more than 50 disorders caused by disease-causing variants of various components of chromatin structure and function. Many of these disorders exhibit unique genome-wide DNA methylation profiles, known as episignatures. In this study, the methylation profile of a large cohort of individuals with chromatinopathies was analyzed for episignature detection.

METHODS

DNA methylation data was generated on extracted blood samples from 129 affected individuals with the Illumina Infinium EPIC arrays and analyzed using an established bioinformatic pipeline.

RESULTS

The DNA methylation profiles matched and confirmed the sequence findings in both the discovery and validation cohorts. Twenty-five affected individuals carrying a variant of uncertain significance, did not show a methylation profile matching any of the known episignatures. Three additional variant of uncertain significance cases with an identified KDM6A variant were re-classified as likely pathogenic (n = 2) or re-assigned as Wolf-Hirschhorn syndrome (n = 1). Thirty of the 33 Next Generation Sequencing negative cases did not match a defined episignature while three matched Kabuki syndrome, Rubinstein-Taybi syndrome and BAFopathy respectively.

CONCLUSION

With the expanding clinical utility of the EpiSign assay, DNA methylation analysis should be considered part of the testing cascade for individuals presenting with clinical features of Mendelian chromatinopathy disorders.

The SGLT2-inhibitor dapagliflozin improves neutropenia and neutrophil dysfunction in a mouse model of the inherited metabolic disorder GSDIb

Glycogen Storage Disease type 1b (GSDIb) is a genetic disorder with long term severe complications. Accumulation of the glucose analog 1,5-anhydroglucitol-6-phosphate (1,5AG6P) in neutrophils inhibits the phosphorylation of glucose in these cells, causing neutropenia and neutrophil dysfunctions. This condition leads to serious infections and inflammatory bowel disease (IBD) in GSDIb patients. We show here that dapagliflozin, an inhibitor of the renal sodium-glucose co-transporter-2 (SGLT2), improves neutrophil function in an inducible mouse model of GSDIb by reducing 1,5AG6P accumulation in myeloid cells.

Risk of autoimmune diseases in patients with RASopathies: systematic study of humoral and cellular immunity

BACKGROUND

Abnormalities of the immune system are rarely reported in patients affected by RASopathies. Aim of the current study was to investigate the prevalence of immune system dysfunction in a cohort of patients affected by RASopathies.

STUDY DESIGN

A group of 69 patients was enrolled: 60 at the Federico II University, Naples, 7 at University Magna Graecia of Catanzaro, 2 at "Scuola Medica Salernitana", Salerno. An age- and sex-matched control group was also enrolled. Autoimmune disorders were investigated according to international consensus criteria. Immune framework was also evaluated by immunoglobulin levels, CD3, CD4, CD8, CD19, CD56 lymphocyte subpopulations, autoantibodies levels and panel of inflammatory molecules, in both patients and controls.

RESULTS

Frequent upper respiratory tract infections were recorded in 2 patients; pneumonia, psoriasis and alopecia in single patients. Low IgA levels were detected in 8/44 patients (18.18%), low CD8 T cells in 13/35 patients (37.14%). Anti-tg and anti-TPO antibodies were detected in 3/24 patients (12.5%), anti r-TSH in 2 cases (8.33%), all in euthyroidism. Serum IgA and CD8 levels were significantly lower in patients than in controls (p 0.00685; p 0.000656 respectively). All tested patients showed increased inflammatory molecules compared to controls. These findings may anticipate the detection of overt autoimmune disease.

CONCLUSIONS

Patients affected by RASopathies are at risk to develop autoimmune disorders. Routine screening for autoimmunity is recommended in patients with RASopathy.

Olfactory bulb enlargement in neurofibromatosis type 1: report of a novel finding

Neurofibromatosis type 1 (NF1) is a genetic autosomal dominant disease caused by mutation of the protein neurofibromin, a regulator of cell growth. The most frequent intracranial findings are unidentified bright objects (UBOs), thickening of the corpus callosum, sphenoid wing dysplasia, cerebral vasculopathy, optic and non-optic pilocytic astrocytomas, and plexiform neurofibromas. We report two cases of NF1 patients with asymptomatic olfactory bulbs (OBs) enlargement depicted with Magnetic Resonance Imaging (MRI). To the best of our knowledge, this finding has not been reported in the scientific literature so far. We hypothesize that olfactory bulbs enlargement may have a pathogenetic nature like that of the UBOs as in one of our patients there was spontaneous regression during follow-up. The olfactory bulbs enlargement expands the broad neuroradiological spectrum of finding of NF1. More reports are required to better understand incidence, pathogenesis, and clinical behavior of olfactory bulbs enlargement in NF1 patients.

Clinical variability of neurofibromatosis 1: A modifying role of cooccurring PTPN11 variants and atypical brain MRI findings

Neurofibromatosis 1 (NF1) is a disorder characterized by variable expressivity caused by loss-of-function variants in NF1, encoding neurofibromin, a protein negatively controlling RAS signaling. We evaluated whether concurrent variation in proteins functionally linked to neurofibromin contribute to the variable expressivity of NF1. Parallel sequencing of a RASopathy gene panel in 138 individuals with molecularly confirmed clinical diagnosis of NF1 identified missense variants in PTPN11, encoding SHP2, a positive regulator of RAS signaling, in four subjects from three unrelated families. Three subjects were heterozygous for a gain-of-function variant and showed a severe expression of NF1 (developmental delay, multiple cerebral neoplasms and peculiar cortical MRI findings), and features resembling Noonan syndrome (a RASopathy caused by activating variants in PTPN11). Conversely, the fourth subject, who showed an attenuated presentation, carried a previously unreported PTPN11 variant that had a hypomorphic behavior in vitro. Our findings document that functionally relevant PTPN11 variants occur in a small but significant proportion of subjects with NF1 modulating disease presentation, suggesting a model in which the clinical expression of pathogenic NF1 variants is modified by concomitant dysregulation of protein(s) functionally linked to neurofibromin. We also suggest targeting of SHP2 function as an approach to treat evolutive complications of NF1.

Copy number variation analysis implicates novel pathways in patients with oculo-auriculo-vertebral-spectrum and congenital heart defects

Oculo-auriculo-vertebral spectrum (OAVS) is a developmental disorder of craniofacial morphogenesis. Its etiology is unclear, but assumed to be complex and heterogeneous, with contribution of both genetic and environmental factors. We assessed the occurrence of copy number variants (CNVs) in a cohort of 19 unrelated OAVS individuals with congenital heart defect. Chromosomal microarray analysis identified pathogenic CNVs in 2/19 (10.5%) individuals, and CNVs classified as variants of uncertain significance in 7/19 (36.9%) individuals. Remarkably, two subjects had small intragenic CNVs involving DACH1 and DACH2, two paralogs coding for key components of the PAX-SIX-EYA-DACH network, a transcriptional regulatory pathway controlling developmental processes relevant to OAVS and causally associated with syndromes characterized by craniofacial involvement. Moreover, a third patient showed a large duplication encompassing DMBX1/OTX3, encoding a transcriptional repressor of OTX2, another transcription factor functionally connected to the DACH-EYA-PAX network. Among the other relevant CNVs, a deletion encompassing HSD17B6, a gene connected with the retinoic acid signaling pathway, whose dysregulation has been implicated in craniofacial malformations, was also identified. Our findings suggest that CNVs affecting gene dosage likely contribute to the genetic heterogeneity of OAVS, and implicate the PAX-SIX-EYA-DACH network as novel pathway involved in the etiology of this developmental trait.

Diagnostic issues faced by a rare disease healthcare network during Covid-19 outbreak: data from the Campania Rare Disease Registry

Background

The aims of this study were: to investigate the capacity of the rare disease healthcare network in Campania to diagnose patients with rare diseases during the outbreak of Covid-19; and to shed light on problematic diagnoses during this period.

Methods

To describe the impact of the Covid-19 pandemic on the diagnosis of patients with rare diseases, a retrospective analysis of the Campania Region Rare Disease Registry was performed. A tailored questionnaire was sent to rare disease experts to investigate major issues during the emergency period.

Results

Prevalence of new diagnoses of rare disease in March and April 2020 was significantly lower than in 2019 (117 versus 317, P < 0.001 and 37 versus 349, P < 0.001, respectively) and 2018 (117 versus 389, P < 0.001 and 37 versus 282, P < 0.001, respectively). Eighty-two among 98 rare disease experts completed the questionnaire. Diagnostic success (95%), access to diagnosis (80%) and follow-up (72%), lack of Personal Protective Equipment (60%), lack of Covid-19 guidelines (50%) and the need for home therapy (78%) were the most important issues raised during Covid-19 outbreak.

Conclusions

This study describes the effects of the Covid-19 outbreak on the diagnosis of rare disease in a single Italian region and investigates potential issues of diagnosis and management during this period.

Genome-Wide DNA Methylation Analysis of a Cohort of 41 Patients Affected by Oculo-Auriculo-Vertebral Spectrum (OAVS)

Oculo-auriculo-vertebral-spectrum (OAVS; OMIM 164210) is a rare disorder originating from abnormal development of the first and second branchial arch. The clinical phenotype is extremely heterogeneous with ear anomalies, hemifacial microsomia, ocular defects, and vertebral malformations being the main features. MYT1, AMIGO2, and ZYG11B gene variants were reported in a few OAVS patients, but the etiology remains largely unknown. A multifactorial origin has been proposed, including the involvement of environmental and epigenetic mechanisms. To identify the epigenetic mechanisms contributing to OAVS, we evaluated the DNA-methylation profiles of 41 OAVS unrelated affected individuals by using a genome-wide microarray-based methylation approach. The analysis was first carried out comparing OAVS patients with controls at the group level. It revealed a moderate epigenetic variation in a large number of genes implicated in basic chromatin dynamics such as DNA packaging and protein-DNA organization. The alternative analysis in individual profiles based on the searching for Stochastic Epigenetic Variants (SEV) identified an increased number of SEVs in OAVS patients compared to controls. Although no recurrent deregulated enriched regions were found, isolated patients harboring suggestive epigenetic deregulations were identified. The recognition of a different DNA methylation pattern in the OAVS cohort and the identification of isolated patients with suggestive epigenetic variations provide consistent evidence for the contribution of epigenetic mechanisms to the etiology of this complex and heterogeneous disorder.

Hepatic Presentation of Late-Onset Multiple Acyl-CoA Dehydrogenase Deficiency (MADD): Case Report and Systematic Review

Diagnosis of pediatric steatohepatitis is a challenging issue due to a vast number of established and novel causes. Here, we report a child with Multiple Acyl-CoA Dehydrogenase Deficiency (MADD) presenting with an underrated muscle weakness, exercise intolerance and an atypically severe steatotic liver involvement. A systematic literature review of liver involvement in MADD was performed as well. Our patient is a 11-year-old otherwise healthy, non-obese, male child admitted for some weakness/asthenia, vomiting and recurrent severe hypertransaminasemia (aspartate and alanine aminotransferases up to ×20 times upper limit of normal). Hepatic ultrasound showed a bright liver. MRI detected mild lipid storage of thighs muscles. A liver biopsy showed a micro-macrovacuolar steatohepatitis with minimal fibrosis. Main causes of hypertransaminasemia were ruled out. Serum aminoacids (increased proline), acylcarnitines (increased C4-C18) and a large excretion of urinary glutaric acid, ethylmalonic, butyric, isobutyric, 2-methyl-butyric and isovaleric acids suggested a diagnosis of MADD. Serum acylcarnitines and urinary organic acids fluctuated overtime paralleling serum transaminases during periods of illness/catabolic stress, confirming their recurrent nature. Genetic testing confirmed the diagnosis [homozygous c.1658A > G (p.Tyr553Cys) in exon 12 of the ETFDH gene]. Lipid-restricted diet and riboflavin treatment rapidly ameliorated symptoms, hepatic ultrasonography/enzymes, and metabolic profiles. Literature review (37 retrieved eligible studies, 283 patients) showed that liver is an extramuscular organ rarely involved in late-onset MADD (70 patients), and that amongst 45 patients who had fatty liver only nine had severe presentation. Conclusion: MADD is a disorder with a clinically heterogeneous phenotype. Our study suggests that MADD warrants consideration in the work-up of obesity-unrelated severe steatohepatitis.

A pilot clinical trial with losartan in Myhre syndrome

Introduction

Myhre syndrome (MS) is an ultra‐rare disorder due to pathogenic variants in the SMAD4 gene that encodes a protein regulating the TGF‐β pathway and extra‐cellular matrix (ECM) homeostasis. Main clinical features of MS include thickening of skin and joint stiffness. Previous studies showed that losartan improved ECM deposition in MS fibroblasts.

Materials and methods

Four molecularly confirmed MS subjects (mean age 23.8 ± 17 years) were evaluated for: (a) skin thickness by Rodnan score, (b) joint range of motion (ROM) by goniometry, and (c) speckle‐tracking echocardiogram. Following baseline evaluations, three MS individuals received losartan for 12 months and pre‐defined endpoints were monitored after 6 and 12 months of treatment.

Results

At baseline, Rodnan scores were increased, joint ROM was reduced, and speckle‐tracking echocardiogram revealed reduced myocardial strain. In three MS subjects, improvements in skin thickness, joint ROM and to a lesser extent of myocardial strain, were observed after 6 and 12 months of losartan treatment.

Conclusions

Although further long‐term controlled clinical trials with a larger number of affected individuals are needed, the present study suggests that losartan might improve skin, joint and heart abnormalities of MS.

Loss-of-function maternal-effect mutations of PADI6 are associated with familial and sporadic Beckwith-Wiedemann syndrome with multi-locus imprinting disturbance

BACKGROUND

PADI6 is a component of the subcortical maternal complex, a group of proteins that is abundantly expressed in the oocyte cytoplasm, but is required for the correct development of early embryo. Maternal-effect variants of the subcortical maternal complex proteins are associated with heterogeneous diseases, including female infertility, hydatidiform mole, and imprinting disorders with multi-locus imprinting disturbance. While the involvement of PADI6 in infertility is well demonstrated, its role in imprinting disorders is less well established.

RESULTS

We have identified by whole-exome sequencing analysis four cases of Beckwith-Wiedemann syndrome with multi-locus imprinting disturbance whose mothers are carriers of PADI6 variants. In silico analysis indicates that these variants result in loss of function, and segregation analysis suggests they act as either recessive or dominant-negative maternal-effect mutations. Genome-wide methylation analysis revealed heterogeneous and extensively altered methylation profiles of imprinted loci in the patients, including two affected sisters, but not in their healthy siblings.

CONCLUSION

Our results firmly establish the role of PADI6 in imprinting disorders. We report loss-of-function maternal-effect variants of PADI6 that are associated with heterogeneous multi-locus imprinting disturbances in the progeny. The rare finding of two siblings affected by Beckwith-Wiedemann syndrome suggests that in some cases, familial recurrence risk of these variants may be high. However, the heterogeneous phenotypes of the other pedigrees suggest that altered oocyte PADI6 function results in stochastic maintenance of methylation imprinting with unpredictable consequences on early embryo health.

Multimodal evaluation of the cerebrovascular reserve in Neurofibromatosis type 1 patients with Moyamoya syndrome

Purpose

Moyamoya syndrome (MMS) is a rare intracranial arterial vasculopathy which can occur in neurofibromatosis type 1 (NF1) disease, representing a cause of cerebrovascular reserve (CVR) impairment, possibly leading to ischemic stroke. Here, we evaluated noninvasive imaging techniques used to assess CVR in MMS patients, describing clinical and imaging findings in patients affected by MMS-NF1.

Methods

Following strict inclusion and exclusion criteria, in this retrospective observational study, we evaluated imaging data of nine consecutive MMS-NF1 patients (M/F = 5/4, mean age: 12.6 ± 4.0). Subjects underwent a multimodal evaluation of cerebral vascular status, including intracranial arterial MR Angiography (MRA), MRI perfusion with dynamic susceptibility contrast (DSC) technique, and 99mTc-hexamethylpropyleneamine oxime (HMPAO) SPECT.

Results

In 8 out 9 patients (88.8%, 6/8 symptomatic), time-to-peak maps were correlated with the involved cerebral hemisphere, while in 6 out 9 patients (66.6%, 5/6 symptomatic), mean transit time (MTT) maps showed correspondence with the affected cerebrovascular territories. Cerebral blood flow (CBF) calculated using DSC perfusion failed to detect the hypoperfused regions instead identified by SPECT-CBF in all patients, while MTT maps overlapped with SPECT-CBF data in all cases and time-to-peak maps in 60.0%.

Conclusions

Although SPECT imaging still represents the gold standard for CBF assessment, our results suggest that data obtained using DSC perfusion technique, and in particular MTT maps, might be a very useful and noninvasive tool for evaluating hemodynamic status in MMS-NF1 patients.

Electronic supplementary material

The online version of this article (10.1007/s10072-020-04574-4) contains supplementary material, which is available to authorized users.

Dietary lipids in glycogen storage disease type III: A systematic literature study, case studies, and future recommendations

A potential role of dietary lipids in the management of hepatic glycogen storage diseases (GSDs) has been proposed, but no consensus on management guidelines exists. The aim of this study was to describe current experiences with dietary lipid manipulations in hepatic GSD patients. An international study was set up to identify published and unpublished cases describing hepatic GSD patients with a dietary lipid manipulation. A literature search was performed according to the Cochrane Collaboration methodology through PubMed and EMBASE (up to December 2018). All delegates who attended the dietetics session at the IGSD2017, Groningen were invited to share unpublished cases. Due to multiple biases, only data on GSDIII were presented. A total of 28 cases with GSDIII and a dietary lipid manipulation were identified. Main indications were cardiomyopathy and/or myopathy. A high fat diet was the most common dietary lipid manipulation. A decline in creatine kinase concentrations (n = 19, P < .001) and a decrease in cardiac hypertrophy in paediatric GSDIIIa patients (n = 7, P < .01) were observed after the introduction with a high fat diet. This study presents an international cohort of GSDIII patients with different dietary lipid manipulations. High fat diet may be beneficial in paediatric GSDIIIa patients with cardiac hypertrophy, but careful long-term monitoring for potential complications is warranted, such as growth restriction, liver inflammation, and hepatocellular carcinoma development.

Refinement of the clinical and mutational spectrum of UBE2A deficiency syndrome

UBE2A deficiency, that is, intellectual disability (ID) Nascimento type (MIM 300860), is an X-linked syndrome characterized by developmental delay, moderate to severe ID, seizures, dysmorphisms, skin anomalies, and urogenital malformations. Forty affected subjects have been reported thus far, with 31 cases having intragenic UBE2A variants. Here, we report on additional eight affected subjects from seven unrelated families who were found to be hemizygous for previously unreported UBE2A missense variants (p.Glu62Lys, p.Arg95Cys, p.Thr99Ala, and p.Arg135Trp) or small in-frame deletions (p.Val81_Ala83del, and p.Asp101del). A wide phenotypic spectrum was documented in these subjects, ranging from moderate ID associated with mild dysmorphisms to severe features including congenital heart defects (CHD), severe cognitive impairment, and pineal gland tumors. Four variants affected residues (Glu62, Arg95, Thr99 and Asp101) that contribute to stabilizing the structure of the E3 binding domain. The three-residue in-frame deletion, p.Val81_Ala83del, resulted from aberrant processing of the transcript. This variant and p.Arg135Trp mapped to regions of the protein located far from the E3 binding region, and caused variably accelerated protein degradation. By reviewing available clinical information, we revise the clinical and molecular profile of the disorder and document genotype-phenotype correlations. Pineal gland cysts/tumors, CHD and hypogammaglobulinemia emerge as recurrent features.

Retrospective Multicentric Study on Non-Optic CNS Tumors in Children and Adolescents with Neurofibromatosis Type 1

s: The natural history of non-optic central nervous system (CNS) tumors in neurofibromatosis type 1 (NF1) is largely unknown. Here, we describe prevalence, clinical presentation, treatment, and outcome of 49 non-optic CNS tumors observed in 35 pediatric patients (0-18 years). Patient- and tumor-related data were recorded. Overall survival (OS) and progression-free survival (PFS) were evaluated. Eighteen patients (51%) harbored an optic pathway glioma (OPG) and eight (23%) had multiple non-optic CNS lesions. The majority of lesions (37/49) were managed with a wait-and-see strategy, with one regression and five reductions observed. Twenty-one lesions (42.9%) required surgical treatment. Five-year OS was 85.3%. Twenty-four patients progressed with a 5-year PFS of 41.4%. Patients with multiple low-grade gliomas progressed earlier and had a lower 5-year PFS than those with one lesion only (14.3% vs. 57.9%), irrespective of OPG co-presence. Non-optic CNS tumors are common in young patients with NF1. Neither age and symptoms at diagnosis nor tumor location influenced time to progression in our series. Patients with multiple lesions tended to have a lower age at onset and to progress earlier, but with a good OS.

Primrose syndrome: Characterization of the phenotype in 42 patients

Primrose syndrome (PS; MIM# 259050) is characterized by intellectual disability (ID), macrocephaly, unusual facial features (frontal bossing, deeply set eyes, down‐slanting palpebral fissures), calcified external ears, sparse body hair and distal muscle wasting. The syndrome is caused by de novo heterozygous missense variants in ZBTB20. Most of the 29 published patients are adults as characteristics appear more recognizable with age. We present 13 hitherto unpublished individuals and summarize the clinical and molecular findings in all 42 patients. Several signs and symptoms of PS develop during childhood, but the cardinal features, such as calcification of the external ears, cystic bone lesions, muscle wasting, and contractures typically develop between 10 and 16 years of age. Biochemically, anemia and increased alpha‐fetoprotein levels are often present. Two adult males with PS developed a testicular tumor. Although PS should be regarded as a progressive entity, there are no indications that cognition becomes more impaired with age. No obvious genotype‐phenotype correlation is present. A subgroup of patients with ZBTB20 variants may be associated with mild, nonspecific ID. Metabolic investigations suggest a disturbed mitochondrial fatty acid oxidation. We suggest a regular surveillance in all adult males with PS until it is clear whether or not there is a truly elevated risk of testicular cancer.

Imbalanced cortisol concentrations in glycogen storage disease type I: evidence for a possible link between endocrine regulation and metabolic derangement

Background

Glycogen storage disease type I (GSDI) is an inborn error of carbohydrate metabolism caused by mutations of either the G6PC gene (GSDIa) or the SLC37A4 gene (GSDIb). Glucose 6-phosphate (G6P) availability has been shown to modulate 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1), an ER-bound enzyme catalyzing the local conversion of inactive cortisone into active cortisol. Adrenal cortex assessment has never been performed in GSDI. The aim of the current study was to evaluate the adrenal cortex hormones levels in GSDI patients.

Methods

Seventeen GSDI (10 GSDIa and 7 GSDIb) patients and thirty-four age and sex-matched controls were enrolled. Baseline adrenal cortex hormones and biochemical markers of metabolic control serum levels were analyzed. Low dose ACTH stimulation test was also performed.

Results

Baseline cortisol serum levels were higher in GSDIa patients (p = 0.042) and lower in GSDIb patients (p = 0.041) than controls. GSDIa patients also showed higher peak cortisol response (p = 0.000) and Cortisol AUC (p = 0.029). In GSDIa patients, serum cholesterol (p = 0.000), triglycerides (p = 0.000), lactate (p = 0.000) and uric acid (p = 0.008) levels were higher and bicarbonate (p = 0.000) levels were lower than controls. In GSDIb patients, serum cholesterol levels (p = 0.016) were lower and lactate (p = 0.000) and uric acid (p = 0.000) levels were higher than controls. Baseline cortisol serum levels directly correlated with cholesterol (ρ = 0.65, p = 0.005) and triglycerides (ρ = 0.60, p = 0.012) serum levels in GSDI patients.

Conclusions

The present study showed impaired cortisol levels in GSDI patients, with opposite trend between GSDIa and GSDIb. The otherwise preserved adrenal cortex function suggests that this finding might be secondary to local deregulation rather than hypothalamo-pituitary-adrenal axis dysfunction in GSDI patients. We hypothesize that 11βHSD1 might represent the link between endocrine regulation and metabolic derangement in GSDI, constituting new potential therapeutic target in GSDI patients.

Customised next-generation sequencing multigene panel to screen a large cohort of individuals with chromatin-related disorder

BACKGROUND

The regulation of the chromatin state by epigenetic mechanisms plays a central role in gene expression, cell function, and maintenance of cell identity. Hereditary disorders of chromatin regulation are a group of conditions caused by abnormalities of the various components of the epigenetic machinery, namely writers, erasers, readers, and chromatin remodelers. Although neurological dysfunction is almost ubiquitous in these disorders, the constellation of additional features characterizing many of these genes and the emerging clinical overlap among them indicate the existence of a community of syndromes. The introduction of high-throughput next generation sequencing (NGS) methods for testing multiple genes simultaneously is a logical step for the implementation of diagnostics of these disorders.

METHODS

We screened a heterogeneous cohort of 263 index patients by an NGS-targeted panel, containing 68 genes associated with more than 40 OMIM entries affecting chromatin function.

RESULTS

This strategy allowed us to identify clinically relevant variants in 87 patients (32%), including 30 for which an alternative clinical diagnosis was proposed after sequencing analysis and clinical re-evaluation.

CONCLUSION

Our findings indicate that this approach is effective not only in disorders with locus heterogeneity, but also in order to anticipate unexpected misdiagnoses due to clinical overlap among cognate disorders. Finally, this work highlights the utility of a prompt diagnosis in such a clinically and genetically heterogeneous group of disorders that we propose to group under the umbrella term of chromatinopathies.

Clinical spectrum of individuals with pathogenic NF1 missense variants affecting p.Met1149, p.Arg1276, and p.Lys1423: genotype-phenotype study in neurofibromatosis type 1

We report 281 individuals carrying a pathogenic recurrent NF1 missense variant at p.Met1149, p.Arg1276, or p.Lys1423, representing three nontruncating NF1 hotspots in the University of Alabama at Birmingham (UAB) cohort, together identified in 1.8% of unrelated NF1 individuals. About 25% (95% confidence interval: 20.5-31.2%) of individuals heterozygous for a pathogenic NF1 p.Met1149, p.Arg1276, or p.Lys1423 missense variant had a Noonan-like phenotype, which is significantly more compared with the "classic" NF1-affected cohorts (all p < .0001). Furthermore, p.Arg1276 and p.Lys1423 pathogenic missense variants were associated with a high prevalence of cardiovascular abnormalities, including pulmonic stenosis (all p < .0001), while p.Arg1276 variants had a high prevalence of symptomatic spinal neurofibromas (p < .0001) compared with "classic" NF1-affected cohorts. However, p.Met1149-positive individuals had a mild phenotype, characterized mainly by pigmentary manifestations without externally visible plexiform neurofibromas, symptomatic spinal neurofibromas or symptomatic optic pathway gliomas. As up to 0.4% of unrelated individuals in the UAB cohort carries a p.Met1149 missense variant, this finding will contribute to more accurate stratification of a significant number of NF1 individuals. Although clinically relevant genotype-phenotype correlations are rare in NF1, each affecting only a small percentage of individuals, together they impact counseling and management of a significant number of the NF1 population.

Prevalence, Type, and Molecular Spectrum of NF1 Mutations in Patients with Neurofibromatosis Type 1 and Congenital Heart Disease

The aim of this study was to assess the prevalence and type of congenital heart disease (CHD) and the associated mutation spectrum in a large series of patients with neurofibromatosis type 1 (NF1), and correlate the mutation type with the presence and subgroups of cardiac defects. The study cohort included 493 individuals with molecularly confirmed diagnosis of NF1 for whom cardiac evaluation data were available. CHD was reported in 62/493 (12.6%) patients. Among these patients, 23/62 (37.1%) had pulmonary valve stenosis/dysplasia, 20/62 (32.3%) had mitral valve anomalies, and 10/62 (16.1%) had septal defects. Other defects occurred as rare events. In this NF1 subcohort, three subjects carried a whole-gene deletion, while 59 were heterozygous for an intragenic mutation. A significantly increased prevalence of non-truncating intragenic mutations was either observed in individuals with CHD (22/59, 37.3%) or with pulmonary valve stenosis (13/20, 65.0%), when compared to individuals without CHD (89/420, 21.2%) (p = 0.038) or pulmonary valve stenosis (98/459, 21.4%) (p = 0.002). Similarly, patients with non-truncating NF1 mutations displayed two- and six-fold higher risk of developing CHD (odds ratio = 1.9713, 95% confidence interval (CI): 1.1162-3.4814, p = 0.0193) and pulmonary valve stenosis (odds ratio = 6.8411, 95% CI: 2.6574-17.6114, p = 0.0001), respectively. Noteworthy, all but one patient (19/20, 95.0%) with pulmonary valve stenosis, and 18/35 (51.4%) patients with other CHDs displayed Noonan syndrome (NS)-like features. Present data confirm the significant frequency of CHD in patients with NF1, and provide further evidence for a higher than expected prevalence of NF1 in-frame variants and NS-like characteristics in NF1 patients with CHD, particularly with pulmonary valve stenosis.

Clinical and Genetic Findings in Children with Neurofibromatosis Type 1, Legius Syndrome, and Other Related Neurocutaneous Disorders

Pigmentary manifestations can represent an early clinical sign in children affected by Neurofibromatosis type 1 (NF1), Legius syndrome, and other neurocutaneous disorders. The differential molecular diagnosis of these pathologies is a challenge that can now be met by combining next generation sequencing of target genes with concurrent second-level tests, such as multiplex ligation-dependent probe amplification and RNA analysis. We clinically and genetically investigated 281 patients, almost all pediatric cases, presenting with either NF1 (n = 150), only pigmentary features (café au lait macules with or without freckling; (n = 95), or clinical suspicion of other RASopathies or neurocutaneous disorders (n = 36). The causative variant was identified in 239 out of the 281 patients analyzed (85.1%), while 42 patients remained undiagnosed (14.9%). The NF1 and SPRED1 genes were mutated in 73.3% and 2.8% of cases, respectively. The remaining 8.9% carried mutations in different genes associated with other disorders. We achieved a molecular diagnosis in 69.5% of cases with only pigmentary manifestations, allowing a more appropriate clinical management of these patients. Our findings, together with the increasing availability and sharing of clinical and genetic data, will help to identify further novel genotype–phenotype associations that may have a positive impact on patient follow-up.

Mutation update for the SATB2 gene

SATB2-associated syndrome (SAS) is an autosomal dominant neurodevelopmental disorder caused by alterations in the SATB2 gene. Here we present a review of published pathogenic variants in the SATB2 gene to date and report 38 novel alterations found in 57 additional previously unreported individuals. Overall, we present a compilation of 120 unique variants identified in 155 unrelated families ranging from single nucleotide coding variants to genomic rearrangements distributed throughout the entire coding region of SATB2. Single nucleotide variants predicted to result in the occurrence of a premature stop codon were the most commonly seen (51/120 = 42.5%) followed by missense variants (31/120 = 25.8%). We review the rather limited functional characterization of pathogenic variants and discuss current understanding of the consequences of the different molecular alterations. We present an expansive phenotypic review along with novel genotype-phenotype correlations. Lastly, we discuss current knowledge of animal models and present future prospects. This review should help provide better guidance for the care of individuals diagnosed with SAS.

Discrepant molecular and clinical diagnoses in Beckwith-Wiedemann and Silver-Russell syndromes

Beckwith-Wiedemann syndrome (BWS) and Silver-Russell syndrome (SRS) are two imprinting disorders associated with opposite molecular alterations in the 11p15.5 imprinting centres. Their clinical diagnosis is confirmed by molecular testing in 50-70% of patients. The authors from different reference centres for BWS and SRS have identified single patients with unexpected and even contradictory molecular findings in respect to the clinical diagnosis. These patients clinically do not fit the characteristic phenotypes of SRS or BWS, but illustrate their clinical heterogeneity. Thus, comprehensive molecular testing is essential for accurate diagnosis and appropriate management, to avoid premature clinical diagnosis and anxiety for the families.

Insulin-resistance in glycogen storage disease type Ia: linking carbohydrates and mitochondria?

BACKGROUND

Glycogen storage disease type I (GSDI) is an inborn error of carbohydrate metabolism caused by mutations of either the G6PC gene (GSDIa) or the SLC37A4 gene (GSDIb). GSDIa patients are at higher risk of developing insulin-resistance (IR). Mitochondrial dysfunction has been implicated in the development of IR. Mitochondrial dysfunction can demonstrate abnormalities in plama acylcarnitines (ACs) and urine organic acids (UOA). The aim of the study was to investigate the presence of mitochondrial impairment in GSDI patients and its possible connection with IR.

METHODS

Fourteen GSDIa, seven GSDIb patients, 28 and 14 age and sex-matched controls, were enrolled. Plasma ACs, UOA, and surrogate markers of IR (HOMA-IR, QUICKI, ISI, VAI) were measured.

RESULTS

GSDIa patients showed higher short-chain ACs and long-chain ACs levels and increased urinary excretion of lactate, pyruvate, 2-ketoglutarate, 3-methylglutaconate, adipate, suberate, aconitate, ethylmalonate, fumarate, malate, sebacate, 4-octenedioate, 3OH-suberate, and 3-methylglutarate than controls (p < 0.05). GSDIb patients showed higher C0 and C4 levels and increased urinary excretion of lactate, 3-methylglutarate and suberate than controls (p < 0.05). In GSDIa patients C18 levels correlated with insulin serum levels, HOMA-IR, QUICKI, and ISI; long-chain ACs levels correlated with cholesterol, triglycerides, ALT serum levels, and VAI.

DISCUSSION

Increased plasma ACs and abnormal UOA profile suggest mitochondrial impairment in GSDIa. Correlation data suggest a possible connection between mitochondrial impairment and IR. We hypothesized that mitochondrial overload might generate by-products potentially affecting the insulin signaling pathway, leading to IR. On the basis of the available data, the possible pathomechanism for IR in GSDIa is proposed.

Whole exome sequencing identifies MRVI1 as a susceptibility gene for moyamoya syndrome in neurofibromatosis type 1

Background and purpose

Moyamoya angiopathy is a progressive cerebral vasculopathy. The p.R4810K substitution in RNF213 has previously been linked to moyamoya disease in Asian populations. When associated with other medical conditions, such as neurofibromatosis type 1, this vasculopathy is frequently reported as moyamoya syndrome. Intriguingly, most cases of moyamoya-complicated neurofibromatosis type 1 have been described in Caucasians, inverting the population ratio observed in Asians, although prevalence of neurofibromatosis type 1 is constant worldwide. Our aim was to investigate whether, among Caucasians, additive genetic factors may contribute to the occurrence of moyamoya in neurofibromatosis type 1.

Methods

Whole exome sequencing was carried out on an Italian family with moyamoya-complicated neurofibromatosis type 1 to identify putative genetic modifiers independent of the NF1 locus and potentially involved in moyamoya pathogenesis. Results were validated in an unrelated family of German ancestry.

Results

We identified the p.P186S substitution (rs35857561) in MRVI1 that segregated with moyamoya syndrome in both the Italian and German family.

Conclusions

The rs35857561 polymorphism in MRVI1 may be a genetic susceptibility factor for moyamoya in European patients with neurofibromatosis type 1. MRVI1 is a functional partner of ITPR1, PRKG1 and GUCY1A3, which are involved in response to nitric oxide. Mutations in GUCY1A3 have been recently linked to a recessive syndromic form of moyamoya with esophageal achalasia.

Sensorineural Hearing Loss in a Patient Affected by Congenital Cytomegalovirus Infection: Is It Useful to Identify Comorbid Pathologies?

Sensorineural hearing loss (SNHL) is a common defect with a multifactorial etiology. Congenital cytomegalovirus infection (cCMV) is the most common infectious cause, and its early detection allows a prompt pharmacological treatment that can improve hearing prognosis. In a consistent percentage of profound SNHL, genetic causes and/or inner ear malformations are involved; their prompt diagnosis might change therapeutic options. This study reports a case of a 3- year-old female patient with symptomatic cCMV infection who also exhibits developmental delay, dysmorphic facial features, bilateral hearing loss, and cochlear incomplete partition, type 2, in 7q21.3 deletion. This deletion includes the genes DLX5 and DLX6 , which could be the candidate genes for the ear malformation named incomplete partition, type 2.

Cutting Edge: Increased Autoimmunity Risk in Glycogen Storage Disease Type 1b Is Associated with a Reduced Engagement of Glycolysis in T Cells and an Impaired Regulatory T Cell Function

Glycogen storage disease type 1b (GSD-1b) is an autosomal-recessive disease caused by mutation of glucose-6-phosphate transporter and characterized by altered glycogen/glucose homeostasis. A higher frequency of autoimmune diseases has been observed in GSD-1b patients, but the molecular determinants leading to this phenomenon remain unknown. To address this question, we investigated the effect of glucose-6-phosphate transporter mutation on immune cell homeostasis and CD4⁺ T cell functions. In GSD-1b subjects, we found lymphopenia and a reduced capacity of T cells to engage glycolysis upon TCR stimulation. These phenomena associated with reduced expression of the FOXP3 transcription factor, lower suppressive function in peripheral CD4⁺CD25⁺FOXP3⁺ regulatory T cells, and an impaired capacity of CD4⁺CD25^- conventional T cells to induce expression of FOXP3 after suboptimal TCR stimulation. These data unveil the metabolic determinant leading to an increased autoimmunity risk in GSD-1b patients.

CREBBP mutations in individuals without Rubinstein-Taybi syndrome phenotype

Mutations in CREBBP cause Rubinstein-Taybi syndrome. By using exome sequencing, and by using Sanger in one patient, CREBBP mutations were detected in 11 patients who did not, or only in a very limited manner, resemble Rubinstein-Taybi syndrome. The combined facial signs typical for Rubinstein-Taybi syndrome were absent, none had broad thumbs, and three had only somewhat broad halluces. All had apparent developmental delay (being the reason for molecular analysis); five had short stature and seven had microcephaly. The facial characteristics were variable; main characteristics were short palpebral fissures, telecanthi, depressed nasal ridge, short nose, anteverted nares, short columella, and long philtrum. Six patients had autistic behavior, and two had self-injurious behavior. Other symptoms were recurrent upper airway infections (n = 5), feeding problems (n = 7) and impaired hearing (n = 7). Major malformations occurred infrequently. All patients had a de novo missense mutation in the last part of exon 30 or beginning of exon 31 of CREBBP, between base pairs 5,128 and 5,614 (codons 1,710 and 1,872). No missense or truncating mutations in this region have been described to be associated with the classical Rubinstein-Taybi syndrome phenotype. No functional studies have (yet) been performed, but we hypothesize that the mutations disturb protein-protein interactions by altering zinc finger function. We conclude that patients with missense mutations in this specific CREBBP region show a phenotype that differs substantially from that in patients with Rubinstein-Taybi syndrome, and may prove to constitute one (or more) separate entities. © 2016 Wiley Periodicals, Inc.

Mulibrey nanism: Two novel mutations in a child identified by Array CGH and DNA sequencing

In childhood, several rare genetic diseases have overlapping symptoms and signs, including those regarding growth alterations, thus the differential diagnosis is sometimes difficult. The proband, aged 3 years, was suspected to have Silver-Russel syndrome because of intrauterine growth retardation, postnatal growth retardation, typical facial dysmorphic features, macrocephaly, body asymmetry, and bilateral fifth finger clinodactyly. Other features were left atrial and ventricular enlargement and patent foramen ovale. Total X-ray skeleton showed hypoplasia of the twelfth rib bilaterally and of the coccyx, slender long bones with thick cortex, and narrow medullary channels. The genetic investigation did not confirm Silver-Russel syndrome. At the age of 5 the patient developed an additional sign: hepatomegaly. Array CGH revealed a 147 kb deletion (involving TRIM 37 and SKA2 genes) on one allele of chromosome 17, inherited from his mother. These results suggested Mulibrey nanism. The clinical features were found to fit this hypothesis. Sequencing of the TRIM 37 gene showed a single base change at a splicing locus, inherited from his father that provoked a truncated protein. The combined use of Array CGH and DNA sequencing confirmed diagnosis of Mulibrey nanism. The large deletion involving the SKA2 gene, along with the increased frequency of malignant tumours in mulibrey patients, suggests closed monitoring for cancer of our patient and his mother. Array CGH should be performed as first tier test in all infants with multiple anomalies. The clinician should reconsider the clinical features when the genetics suggests this. © 2016 Wiley Periodicals, Inc.

Reduced bone mineral density in glycogen storage disease type III: evidence for a possible connection between metabolic imbalance and bone homeostasis

INTRODUCTION

Glycogen storage disease type III (GSDIII) is an inborn error of carbohydrate metabolism caused by deficient activity of glycogen debranching enzyme (GDE). It is characterized by liver, cardiac muscle and skeletal muscle involvement. The presence of systemic complications such as growth retardation, ovarian polycystosis, diabetes mellitus and osteopenia/osteoporosis has been reported. The pathogenesis of osteopenia/osteoporosis is still unclear.

OBJECTIVES

The aim of the current study was to evaluate the bone mineral density (BMD) in GSDIII patients and the role of metabolic and endocrine factors and physical activity on bone status.

METHODS

Nine GSDIII patients were enrolled (age 2-20years) and compared to eighteen age and sex matched controls. BMD was evaluated by Dual-emission-X-ray absorptiometry (DXA) and Quantitative ultrasound (QUS). Clinical and biochemical parameters of endocrine system function and bone metabolism were analyzed. Serum levels of the metabolic control markers were evaluated. Physical activity was evaluated by administering the International Physical Activity Questionnaire (IPAQ).

RESULTS

GSDIII patients showed reduced BMD detected at both DXA and QUS, decreased serum levels of IGF-1, free IGF-1, insulin, calcitonin, osteocalcin (OC) and increased serum levels of C-terminal cross-linking telopeptide of type I collagen (CTX). IGF-1 serum levels inversely correlated with AST and ALT serum levels. DXA Z-score inversely correlated with cholesterol and triglycerides serum levels and directly correlated with IGF-1/IGFBP3 molar ratio. No difference in physical activity was observed between GSDIII patients and controls.

DISCUSSION

Our data confirm the presence of reduced BMD in GSDIII. On the basis of the results, we hypothesized that metabolic imbalance could be the key factor leading to osteopenia, acting through different mechanisms: chronic hyperlipidemia, reduced IGF-1, Insulin and OC serum levels. Thus, the mechanism of osteopenia/osteoporosis in GSDIII is probably multifactorial and we speculate on the factors involved in its pathogenesis.

New insights in the interpretation of array-CGH: autism spectrum disorder and positive family history for intellectual disability predict the detection of pathogenic variants

BACKGROUND

Array-CGH (aCGH) is presently used into routine clinical practice for diagnosis of patients with intellectual disability (ID), multiple congenital anomalies (MCA), and autism spectrum disorder (ASD). ACGH could detect small chromosomal imbalances, copy number variations (CNVs), and closely define their size and gene content. ACGH detects pathogenic imbalances in 14-20 % of patients with ID. The aims of this study were: to establish clinical clues potentially associated with pathogenic CNVs and to identify cytogenetic indicators to predict the pathogenicity of the variants of uncertain significance (VOUS) in a large cohort of paediatric patients.

METHODS

We enrolled 214 patients referred for either: ID, and/or ASD and/or MCA to genetic services at the Federico II University of Naples, Department of Translational Medicine. For each patient we collected clinical and imaging data. All the patients were tested with aCGH or as first-tier test or as part of a wider diagnostic work-up.

RESULTS

Pathologic data were detected in 65 individuals (30 %) and 46 CNVs revealed a known syndrome. The pathological CNVs were usually deletions showing the highest gene-dosage content. The positive family history for ID/ASD/MCA and ASD were good indicators for detecting pathological chromosomal rearrangements. Other clinical features as eyes anomalies, hearing loss, neurological signs, cutaneous dyscromia and endocrinological problems seem to be potential predictors of pathological CNVs. Among patients carrying VOUS we analyzed genetic features including CNVs size, presence of deletion or duplication, genic density, multiple CNVs, to clinical features. Higher gene density was found in patients affected by ID. This result suggest that higher gene content has more chances to include pathogenic gene involved and causing ID in these patients.

CONCLUSION

Our study suggest the use of aCGH as first-tier test in patients with neurdevelopmental phenotypes. The inferred results have been used for building a flow-chart to be applied for children with ID.

Fetal growth patterns in Beckwith-Wiedemann syndrome

We provide data on fetal growth pattern on the molecular subtypes of Beckwith-Wiedemann syndrome (BWS): IC1 gain of methylation (IC1-GoM), IC2 loss of methylation (IC2-LoM), 11p15.5 paternal uniparental disomy (UPD), and CDKN1C mutation. In this observational study, gestational ages and neonatal growth parameters of 247 BWS patients were compared by calculating gestational age-corrected standard deviation scores (SDS) and proportionality indexes to search for differences among IC1-GoM (n = 21), UPD (n = 87), IC2-LoM (n = 147), and CDKN1C mutation (n = 11) patients. In IC1-GoM subgroup, weight and length are higher than in other subgroups. Body proportionality indexes display the following pattern: highest in IC1-GoM patients, lowest in IC2-LoM/CDKN1C patients, intermediate in UPD ones. Prematurity was significantly more prevalent in the CDKN1C (64%) and IC2-LoM subgroups (37%). Fetal growth patterns are different in the four molecular subtypes of BWS and remarkably consistent with altered gene expression primed by the respective molecular mechanisms. IC1-GoM cases show extreme macrosomia and severe disproportion between weight and length excess. In IC2-LoM/CDKN1C patients, macrosomia is less common and associated with more proportionate weight/length ratios with excess of preterm birth. UPD patients show growth patterns closer to those of IC2-LoM, but manifest a body mass disproportion rather similar to that seen in IC1-GoM cases.

A multi-method approach to the molecular diagnosis of overt and borderline 11p15.5 defects underlying Silver-Russell and Beckwith-Wiedemann syndromes

BACKGROUND

Multiple (epi)genetic defects affecting the expression of the imprinted genes within the 11p15.5 chromosomal region underlie Silver-Russell (SRS) and Beckwith-Wiedemann (BWS) syndromes. The molecular diagnosis of these opposite growth disorders requires a multi-approach flowchart to disclose known primary and secondary (epi)genetic alterations; however, up to 20 and 30 % of clinically diagnosed BWS and SRS cases remain without molecular diagnosis. The complex structure of the 11p15 region with variable CpG methylation and low-rate mosaicism may account for missed diagnoses. Here, we demonstrate the relevance of complementary techniques for the assessment of different CpGs and the importance of testing multiple tissues to increase the SRS and BWS detection rate.

RESULTS

Molecular testing of 147 and 450 clinically diagnosed SRS and BWS cases provided diagnosis in 34 SRS and 185 BWS patients, with 9 SRS and 21 BWS cases remaining undiagnosed and herein referred to as "borderline." A flowchart including complementary techniques and, when applicable, the analysis of buccal swabs, allowed confirmation of the molecular diagnosis in all borderline cases. Comparison of methylation levels by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) in borderline and control cases defined an interval of H19/IGF2:IG-DMR loss of methylation that was distinct between "easy to diagnose" and "borderline" cases, which were characterized by values ≤mean -3 standard deviations (SDs) compared to controls. Values ≥mean +1 SD at H19/IGF2: IG-DMR were assigned to borderline hypermethylated BWS cases and those ≤mean -2 SD at KCNQ1OT1: TSS-DMR to hypomethylated BWS cases; these were supported by quantitative pyrosequencing or Southern blot analysis. Six BWS cases suspected to carry mosaic paternal uniparental disomy of chromosome 11 were confirmed by SNP array, which detected mosaicism till 10 %. Regarding the clinical presentation, borderline SRS were representative of the syndromic phenotype, with exception of one patient, whereas BWS cases showed low frequency of the most common features except hemihyperplasia.

CONCLUSIONS

A conclusive molecular diagnosis was reached in borderline methylation cases, increasing the detection rate by 6 % for SRS and 5 % for BWS cases. The introduction of complementary techniques and additional tissue analyses into routine diagnostic work-up should facilitate the identification of cases undiagnosed because of mosaicism, a distinctive feature of epigenetic disorders.