Long-term outcome of a cohort of Italian patients affected with alpha-Mannosidosis.

Alpha-mannosidosis (MIM #248500) is an ultra-rare autosomal recessive lysosomal storage disease with multi-system involvement and a wide phenotypic spectrum. Information on long-term outcomes remains poor. We present the long-term outcomes (median, 19 years) of nine patients with alpha-mannosidosis, three females and six males, followed at a single center. The findings of the nine patients were collected from medical records and reported as mean ± SD or median, and range. The age of onset of the first symptoms ranged from 0-1 to 10 years. The diagnostic delay ranged from 2 to 22 years (median= 11 years). Coarse face, hearing, heart valves, joints, gait, language, dysarthria, psychiatric symptoms, I.Q., MRI, walking disabilities, orthopedic disturbances and surgeries showed a slow worsening over the decades. Our patients showed a slowly worsening progressive outcome over the decades. Psychiatric symptoms were present in 100% of our population and improved with the appropriate pharmacological intervention. This aspect requires attention when following up on these patients. Our description of the long-term evolution of alpha-mannosidosis patients may provide basic knowledge for understanding the effects of specific treatments.

A GWAS in the pandemic epicenter highlights the severe COVID-19 risk locus introgressed by Neanderthals.

Large GWAS indicated that genetic factors influence the response to SARS-CoV-2. However, sex, age, concomitant diseases, differences in ancestry, and uneven exposure to the virus impacted the interpretation of data. We aimed to perform a GWAS of COVID-19 outcome in a homogeneous population who experienced a high exposure to the virus and with a known infection status. We recruited inhabitants of Bergamo province-that in spring 2020 was the epicenter of the SARS-Cov-2 pandemic in Europe-via an online questionnaire followed by personal interviews. Cases and controls were matched by age, sex and risk factors. We genotyped 1195 individuals and replicated the association at the 3p21.31 locus with severity, but with a stronger effect size that further increased in gravely ill patients. Transcriptome-wide association study highlighted eQTLs for LZTFL1 and CCR9. We also identified 17 loci not previously reported, suggestive for an association with either COVID-19 severity or susceptibility.

Distribution of Exonic Variants in Glycogen Synthesis and Catabolism Genes in Late Onset Pompe Disease (LOPD).

Pompe disease (PD) is a monogenic autosomal recessive disorder caused by biallelic pathogenic variants of the GAA gene encoding lysosomal alpha-glucosidase; its loss causes glycogen storage in lysosomes, mainly in the muscular tissue. The genotype-phenotype correlation has been extensively discussed, and caution is recommended when interpreting the clinical significance of any mutation in a single patient. As there is no evidence that environmental factors can modulate the phenotype, the observed clinical variability in PD suggests that genetic variants other than pathogenic GAA mutations influence the mechanisms of muscle damage/repair and the overall clinical picture. Genes encoding proteins involved in glycogen synthesis and catabolism may represent excellent candidates as phenotypic modifiers of PD. The genes analyzed for glycogen synthesis included UGP2, glycogenin (GYG1-muscle, GYG2, and other tissues), glycogen synthase (GYS1-muscle and GYS2-liver), GBE1, EPM2A, NHLRC1, GSK3A, and GSK3B. The only enzyme involved in glycogen catabolism in lysosomes is α-glucosidase, which is encoded by GAA, while two cytoplasmic enzymes, phosphorylase (PYGB-brain, PGL-liver, and PYGM-muscle) and glycogen debranching (AGL) are needed to obtain glucose 1-phosphate or free glucose. Here, we report the potentially relevant variants in genes related to glycogen synthesis and catabolism, identified by whole exome sequencing in a group of 30 patients with late-onset Pompe disease (LOPD). In our exploratory analysis, we observed a reduced number of variants in the genes expressed in muscles versus the genes expressed in other tissues, but we did not find a single variant that strongly affected the phenotype. From our work, it also appears that the current clinical scores used in LOPD do not describe muscle impairment with enough qualitative/quantitative details to correlate it with genes that, even with a slightly reduced function due to genetic variants, impact the phenotype.

Mutation Analysis of PKD1 and PKD2 Genes in a Large Italian Cohort Reveals Novel Pathogenic Variants Including A Novel Complex Rearrangement.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited disease of the kidney. It occurs in adulthood but is also rarely diagnosed in early childhood. The majority of the disease-causing variants observed in ADPKD patients are in two genes: PKD1 and PKD2. METHODS: 237 patients from 198 families with a clinical diagnosis of ADPKD were screened for PKD1 and PKD2 genetic variants using Sanger sequencing and Multiple Ligation-dependent Probe Amplification (MLPA) analysis. RESULTS: Disease-causing (diagnostic) variants were identified in 173 families (211 patients), 156 on PKD1 and 17 on PKD2. Variants of unknown significance (VUS) were detected in 6 additional families, while no mutations were found in the remaining 19 families. Among the diagnostic variants detected, 51 were novel. In ten families, seven large rearrangements were found and the molecular breakpoints of 3 rearrangements were identified. Renal survival was significantly worse for PKD1 mutated patients, particularly those carrying truncating mutations. In patients with PKD1 truncating ( PKD1-T) mutations, disease onset was significantly earlier than in patients with PKD1 non-truncating (PKD1-NT) variants or PKD2 mutated patients. CONCLUSIONS: Comprehensive genetic testing confirms its utility in diagnosing patients with ADPKD and contributes to explaining the clinical heterogeneity observed in this disease. Moreover, the genotype-phenotype correlation can allow a more accurate disease prognosis.

CFH and CFHR structural variants in atypical Hemolytic Uremic Syndrome: Prevalence, genomic characterization and impact on outcome.

Introduction: Atypical hemolytic uremic syndrome (aHUS) is a rare disease that manifests with microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure, and is associated with dysregulation of the alternative complement pathway. The chromosomal region including CFH and CFHR1-5 is rich in repeated sequences, favoring genomic rearrangements that have been reported in several patients with aHUS. However, there are limited data on the prevalence of uncommon CFH-CFHR genomic rearrangements in aHUS and their impact on disease onset and outcomes. Methods: In this study, we report the results of CFH-CFHR Copy Number Variation (CNV) analysis and the characterization of resulting structural variants (SVs) in a large cohort of patients, including 258 patients with primary aHUS and 92 with secondary forms. Results: We found uncommon SVs in 8% of patients with primary aHUS: 70% carried rearrangements involving CFH alone or CFH and CFHR (group A; n=14), while 30% exhibited rearrangements including only CFHRs (group B; n=6). In group A, 6 patients presented CFH::CFHR1 hybrid genes, 7 patients carried duplications in the CFH-CFHR region that resulted either in the substitution of the last CFHR1 exon(s) with those of CFH (CFHR1::CFH reverse hybrid gene) or in an internal CFH duplication. In group A, the large majority of aHUS acute episodes not treated with eculizumab (12/13) resulted in chronic ESRD; in contrast, anti-complement therapy induced remission in 4/4 acute episodes. aHUS relapse occurred in 6/7 grafts without eculizumab prophylaxis and in 0/3 grafts with eculizumab prophylaxis. In group B, 5 subjects had the CFHR31-5::CFHR410 hybrid gene and one had 4 copies of CFHR1 and CFHR4. Compared with group A, patients in group B exhibited a higher prevalence of additional complement abnormalities and earlier disease onset. However, 4/6 patients in this group underwent complete remission without eculizumab treatment. In secondary forms we identified uncommon SVs in 2 out of 92 patients: the CFHR31-5::CFHR410 hybrid and a new internal duplication of CFH. Discussion: In conclusion, these data highlight that uncommon CFH-CFHR SVs are frequent in primary aHUS and quite rare in secondary forms. Notably, genomic rearrangements involving the CFH are associated with a poor prognosis but carriers respond to anti-complement therapy.

PRDX1 gene-related epi-cblC disease is a common type of inborn error of cobalamin metabolism with mono- or bi-allelic MMACHC epimutations.

BACKGROUND: The role of epigenetics in inborn errors of metabolism (IEMs) is poorly investigated. Epigenetic changes can contribute to clinical heterogeneity of affected patients but could also be underestimated determining factors in the occurrence of IEMs. An epigenetic cause of IEMs has been recently described for the autosomal recessive methylmalonic aciduria and homocystinuria, cblC type (cblC disease), and it has been named epi-cblC. Epi-cblC has been reported in association with compound heterozygosity for a genetic variant and an epimutation at the MMACHC locus, which is secondary to a splicing variant (c.515-1G > T or c.515-2A > T) at the adjacent PRDX1 gene. Both these variants cause aberrant antisense transcription and cis-hypermethylation of the MMACHC gene promotor with subsequent silencing. Until now, only nine epi-cblC patients have been reported. METHODS: We report clinical/biochemical assessment, MMACHC/PRDX1 gene sequencing and genome-wide DNA methylation profiling in 11 cblC patients who had an inconclusive MMACHC gene testing. We also compare clinical phenotype of epi-cblC patients with that of canonical cblC patients. RESULTS: All patients turned out to have the epi-cblC disease. One patient had a bi-allelic MMACHC epimutation due to the homozygous PRDX1:c.515-1G > T variant transmitted by both parents. We found that the bi-allelic epimutation produces the complete silencing of MMACHC in the patient's fibroblasts. The remaining ten patients had a mono-allelic MMACHC epimutation, due to the heterozygous PRDX1:c.515-1G > T, in association with a mono-allelic MMACHC genetic variant. Epi-cblC disease has accounted for about 13% of cblC cases diagnosed by newborn screening in the Tuscany and Umbria regions since November 2001. Comparative analysis showed that clinical phenotype of epi-cblC patients is similar to that of canonical cblC patients. CONCLUSIONS: We provide evidence that epi-cblC is an underestimated cause of inborn errors of cobalamin metabolism and describe the first instance of epi-cblC due to a bi-allelic MMACHC epimutation. MMACHC epimutation/PRDX1 mutation analyses should be part of routine genetic testing for all patients presenting with a metabolic phenotype that combines methylmalonic aciduria and homocystinuria.

Morquio B disease: From pathophysiology towards diagnosis.

Morquio B disease is an attenuated phenotype within the spectrum of beta galactosidase (GLB1) deficiencies. It is characterised by dysostosis multiplex, ligament laxity, mildly coarse facies and heart valve defects due to keratan sulphate accumulation, predominantly in the cartilage. Morquio B patients have normal neurological development, setting them apart from those with the more severe GM1 gangliosidosis. Morquio B disease, with an incidence of 1:250.000 to 1:1.000.000 live births, is very rare. Here we report the clinical-biochemical data of nine patients. High amounts of keratan sulfate were detected using LC-MS/MS in the patients' urinary samples, while electrophoresis, the standard procedure of qualitative glycosaminoglycans analysis, failed to identify this metabolite in any of the patients' samples. We performed molecular analyses at gene, gene expression and protein expression levels, for both isoforms of the GLB1 gene, lysosomal GLB1, and the cell-surface expressed Elastin Binding Protein. We characterised three novel GLB1 mutations [c.75 + 2 T > G, c.575A > G (p.Tyr192Cys) and c.2030 T > G (p.Val677Gly)] identified in three heterozygous patients. We also set up a copy number variation assay by quantitative PCR to evaluate the presence of deletions/ insertions in the GLB1 gene. We propose a diagnostic plan, setting out the specific clinical- biochemical and molecular features of Morquio B, in order to avoid misdiagnoses and improve patients' management.

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.

Novel mutations in two unrelated Italian patients with SSADH deficiency.

Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a rare autosomal recessive disorder of γ-aminobutyric acid (GABA) catabolism caused by mutations in the gene coding for succinic semialdehyde dehydrogenase (ALDH5A1). The abnormal levels of GHB detected in the brain and in all physiological fluids of SSADHD patients represent a diagnostic biochemical hallmark of the disease. Here we report on the clinical and molecular characterization of two unrelated Italian patients and the identification of two novel mutations: a 22 bp DNA duplication in exon 1, c.114_135dup, p.(C46AfsX97), and a non-sense mutation in exon 10, c.1429C > T, p.(Q477X). The two patients showed very different clinical phenotypes, coherent with their age. These findings enrich the characterization of SSADHD families and contribute to the knowledge on the progression of the disease.

Chronic liver involvement in urea cycle disorders.

The increased survival of urea cycle disorders (UCDs) patients has led the attention to clinical manifestations that characterize the long-term disease course. Acute and chronic liver disease have been anecdotally reported since the very first description of UCDs. However, a detailed analysis of long-term liver involvement in large patient cohorts is still needed. Chronic liver damage in UCDs has probably a multifactorial origin, but the specific underlying mechanisms of liver disease have not yet been well elucidated. In this study, we report on chronic liver involvement and on associated metabolic abnormalities in a large cohort of 102 UCD patients, followed by two reference centers in Italy. Chronic liver involvement was observed in over 60% of UCDs patients, and comparison between individual diseases showed a significant higher frequency in argininosuccinate lyase deficiency (ASLD) and in hyperornithinemia-hyperammonemia-homocitrullinemia (HHH) syndrome with elevation of transaminases and of gamma-GT in ASLD, and of alpha-fetoprotein in HHH syndrome. Also, consistent with a chronic hepatic dysfunction, ultrasound examination revealed more pronounced abnormalities in ASLD and in HHH syndrome, when compared to other UCDs. Our study highlights in a large UCDs patients' cohort that chronic liver disease is a common finding in UCDs, often with a distinct phenotype between different diseases. Furthers studies are needed to elucidate the specific involvement of different metabolic pathways in the pathogenesis of liver dysfunction in UCDs.

Resting energy expenditure in argininosuccinic aciduria and in other urea cycle disorders.

No data are available on the specific energy needs of patients affected with Urea Cycle disorders (UCD) and especially argininosuccinic aciduria (ASA). In our experience, ASA patients tend to develop central adiposity and hypertriglyceridemia when treated with apparently adequate energy intake, while the other UCD do not. The aim of this study was to evaluate anthropometric parameters, body composition, risk of metabolic syndrome (MS) and resting energy expenditure (REE), both by indirect calorimetry (IC) and predictive equations, in UCD patients. Hypertension (5/13), pathological waist circumference-to-height ratio (WtHr) (6/13), hypertriglyceridemia (12/13), reduced HDL cholesterol (12/13), and MS (5/13) were found in ASA group. In the ASA cohort, the mean and median IC-REE were 88% of what was predicted by Food and Agriculture Organization of the United Nations and Harris-Benedict equations. The "other UCD" cohort did not show hypertension, dyslipidaemia nor MS; IC-REE was similar to the REE predicted by equations. A significant difference was seen for the presence of hypertension, dyslipidaemia, pathological WtHr, MS and IC-REE/predictive equations-REE in the two cohorts. ASA patients have a risk of overfeeding if their energy requirement is not assessed individually with IC. Excessive energy intake might increase the cardiovascular risk of ASA patients. We suggest to test ASA individuals with IC every year if the patient is sufficiently collaborative. We speculate that most of the features seen in ASA patients might depend on an imbalance of Krebs cycle. Further studies are needed to verify this hypothesis.

Refining the Phenotype of Recurrent Rearrangements of Chromosome 16.

Chromosome 16 is one of the most gene-rich chromosomes of our genome, and 10% of its sequence consists of segmental duplications, which give instability and predisposition to rearrangement by the recurrent mechanism of non-allelic homologous recombination. Microarray technologies have allowed for the analysis of copy number variations (CNVs) that can contribute to the risk of developing complex diseases. By array comparative genomic hybridization (CGH) screening of 1476 patients, we detected 27 cases with CNVs on chromosome 16. We identified four smallest regions of overlapping (SROs): one at 16p13.11 was found in seven patients; one at 16p12.2 was found in four patients; two close SROs at 16p11.2 were found in twelve patients; finally, six patients were found with atypical rearrangements. Although phenotypic variability was observed, we identified a male bias for Childhood Apraxia of Speech associated to 16p11.2 microdeletions. We also reported an elevated frequency of second-site genomic alterations, supporting the model of the second hit to explain the clinical variability associated with CNV syndromes. Our goal was to contribute to the building of a chromosome 16 disease-map based on disease susceptibility regions. The role of the CNVs of chromosome 16 was increasingly made clear in the determination of developmental delay. We also found that in some cases a second-site CNV could explain the phenotypic heterogeneity by a simple additive effect or a pejorative synergistic effect.

Clinical hints to diagnosis of attenuated forms of Mucopolysaccharidoses.

The mucopolysaccharidoses (MPS) are clinically similar but also heterogeneous in terms of major or minor involvement of different organs/systems, burden of disease, and rate of progression. The attenuated forms of MPS, due to their less severe presentations, are more difficult to diagnose and often receive a significantly delayed diagnosis. On the other hand, the diagnosis is very important since the attenuated forms may benefit from earlier treatments. The aim of this paper is to describe the natural history and the clinical signs useful to arise a suspicion of an attenuated form of MPS. MPS patients usually show a cluster of signs and symptoms, one of which may be the trigger for an evaluation by a specialist. Individuals with attenuated MPS are mostly cognitively normal, and dysmorphisms of the facies may be mild or absent. The most frequently involved organs/systems are the osteoarticular system, heart, and eyes. These patients may also have hepatosplenomegaly, hearing loss, and respiratory problems. When they are referred to a specialist (rheumatologist, cardiologist, ophthalmologist, surgeon, orthopedist, etc.) for their main complaint, the other signs and symptoms are likely to be missed in the medical history. To avoid missing data and to save time, we propose a semistructured medical history form to be filled in by the patients or their caregivers while waiting for evaluation by a specialist.

A new case report of severe mucopolysaccharidosis type VII: diagnosis, treatment with haematopoietic cell transplantation and prenatal diagnosis in a second pregnancy.

A new patient with severe mucopolysaccharidosis (MPS) type VII is reported. Non-immune hydrops fetalis (NIHF) was diagnosed during pregnancy. At birth, he showed generalized hydrops and dysmorphic features typical of MPS. Many diagnoses were excluded before reaching the diagnosis of MPS VII at 8 months of life. During the first year of life he had frequent respiratory infections associated with restrictive and obstructive bronchopneumopathy and underwent three surgical interventions: decompression of the spinal cord at the craniocervical junction, bilateral inguinal hernia, and bilateral clubfoot. At 14 months of life he underwent successful haematopoietic cell transplantation (HCT). During the following 10 months, his bronchopneumopathy progressively worsened, needing chronic pharmacological treatment and O2 administration. The patient died of respiratory insufficiency during a respiratory syncytial virus infection at 25 months of age. Molecular analysis showed the homozygous variant c.1617C > T, leading to the synonymous mutation p.Ser539=. This caused aberrant splicing with partial skipping of exon 10 (r.1616_1653del38) and complete skipping of exon 9 (r.1392_1476del85; r.1616_1653del38). No transcript of normal size was evident. The parents were both confirmed to be carriers. In a subsequent pregnancy, a prenatal diagnosis showed an affected fetus. Ultrasound examination before abortion showed NIHF. The skin and placenta examination by electron microscopy showed foamy intracytoplasmic vacuoles with a weakly electron-dense substrate. MPS VII is a very rare disease but it is possible that some cases go undiagnosed for several reasons, including that MPS VII, and other lysosomal storage diseases, are not included in the work-up for NIHF in many institutions, and the presence of anasarca at birth may be confounding for the recognition of the typical facial characteristics of the disease. This is the eighth patient affected by MPS VII who has undergone HCT. It is not possible to draw conclusions about the efficacy of HCT in MPS VII. Treatment with enzyme replacement is now available and will probably be beneficial for the patients who have a milder form with no or little cognitive involvement. Increased awareness among clinicians is needed for prompt diagnosis and to offer the correct treatment as early as possible.

Mis-splicing of the GALNS gene resulting from deep intronic mutations as a cause of Morquio a disease.

BACKGROUND: Mucopolysaccharidosis-IVA (Morquio A disease) is a lysosomal disorder in which the abnormal accumulation of keratan sulfate and chondroitin-6-sulfate is consequent to mutations in the galactosamine-6-sulfatase (GALNS) gene. Since standard DNA sequencing analysis fails to detect about 16% of GALNS mutant alleles, gross DNA rearrangement screening and uniparental disomy evaluation are required to complete the molecular diagnosis. Despite this, the second pathogenic GALNS allele generally remains unidentified in ~ 5% of Morquio-A disease patients. METHODS: In an attempt to bridge the residual gap between clinical and molecular diagnosis, we performed an mRNA-based evaluation of three Morquio-A disease patients in whom the second mutant GALNS allele had not been identified. We also performed sequence analysis of the entire GALNS gene in two patients. RESULTS: Different aberrant GALNS mRNA transcripts were characterized in each patient. Analysis of these transcripts then allowed the identification, in one patient, of a disease-causing deep intronic GALNS mutation. The aberrant mRNA products identified in the other two individuals resulted in partial exon loss. Despite sequencing the entire GALNS gene region in these patients, the identity of a single underlying pathological lesion could not be unequivocally determined. We postulate that a combination of multiple variants, acting in cis, may synergise in terms of their impact on the splicing machinery. CONCLUSIONS: We have identified GALNS variants located within deep intronic regions that have the potential to impact splicing. These findings have prompted us to incorporate mRNA analysis into our diagnostic flow procedure for the molecular analysis of Morquio A disease.

Familiar unbalanced complex rearrangements involving 13 p-arm: description of two cases.

BACKGROUND: Copy number variations (CNVs) are largely known today, but their position is rarely established by fluorescence in situ hybridization (FISH) or karyotype analysis. CASE PRESENTATION: We described two families with copy number gain in which FISH analysis with the specific subtelomeric probe of chromosome 4q and 7q evidenced a third signal at band 13p11.2. Genomic study by array comparative genomic hybridization defined the triple dose segment. In the first case, the duplicate tract is free of known genes, in the second one it contained three expressed genes. CONCLUSIONS: The CNV localization on the short arm of an acrocentric chromosome could explain the lack of phenotypic effect, being known the regulatory role of heterochromatin in the position-effect silencing. Furthermore, we would like to underline the importance of using complementary techniques such as FISH and array-CGH to obtain a better definition of genomic rearrangements.

Improving the diagnosis of cobalamin and related defects by genomic analysis, plus functional and structural assessment of novel variants.

BACKGROUND: Cellular cobalamin defects are a locus and allelic heterogeneous disorder. The gold standard for coming to genetic diagnoses of cobalamin defects has for some time been gene-by-gene Sanger sequencing of individual DNA fragments. Enzymatic and cellular methods are employed before such sequencing to help in the selection of the gene defects to be sought, but this is time-consuming and laborious. Furthermore some cases remain undiagnosed because no biochemical methods have been available to test for cobalamin absorption and transport defects. RESULTS: This paper reports the use of massive parallel sequencing of DNA (exome analysis) for the accurate and rapid genetic diagnosis of cobalamin-related defects in a cohort of affected patients. The method was first validated in an initial cohort with different cobalamin defects. Mendelian segregation, the frequency of mutations, and the comprehensive structural and functional analysis of gene variants, identified disease-causing mutations in 12 genes involved in the absorption and synthesis of active cofactors of vitamin B12 (22 cases), and in the non-cobalamin metabolism-related genes ACSF3 (in four biochemically misdiagnosed patients) and SUCLA2 (in one patient with an unusual presentation). We have identified thirteen new variants all classified as pathogenic according to the ACGM recommendation but four were classified as variant likely pathogenic in MUT and SUCLA2. Functional and structural analysis provided evidences to classify them as pathogenic variants. CONCLUSIONS: The present findings suggest that the technology used is sufficiently sensitive and specific, and the results it provides sufficiently reproducible, to recommend its use as a second-tier test after the biochemical detection of cobalamin disorder markers in the first days of life. However, for accurate diagnoses to be made, biochemical and functional tests that allow comprehensive clinical phenotyping are also needed.

Hepatocellular carcinoma in Gaucher disease: an international case series.

Gaucher disease (GD) is associated with an increased risk for malignancies. Next to hematological malignancies, the development of solid tumors in several organs has been described. The liver is one of the major storage sites involved in GD pathogenesis, and is also affected by liver-specific complications. In this case series, we describe 16 GD type 1 (GD1) patients from eight different referral centers around the world who developed hepatocellular carcinoma (HCC). Potential factors contributing to the increased HCC risk in GD patients are studied. Eleven patients had undergone a splenectomy in the past. Liver cirrhosis, one of the main risk factors for the development of HCC, was present in nine out of 14 patients for whom data was available. Three out of seven examined patients showed a transferrin saturation > 45%. In these three patients the presence of iron overload after histopathological examination of the liver was shown. Chronic hepatitis C infection was present in three of 14 examined cases. We summarized all findings and made a comparison to the literature. We recommend that GD patients, especially those with prior splenectomy or iron overload, be evaluated for signs of liver fibrosis and if found to be monitored for HCC development.

Progression of renal damage in glycogen storage disease type I is associated to hyperlipidemia: a multicenter prospective Italian study.

Angiotensin converting enzyme (ACE)-inhibitors decrease glomerular hyperfiltration but not microalbuminuria and proteinuria in glycogen storage disease type I. In the current study, we demonstrated that severe hyperlipidemia is associated with ACE-inhibitor ineffectiveness. We underline the importance of adequate metabolic control in glycogen storage disease type I. A combination therapy with ACE-inhibitors and lipid lowering drugs might be considered.

Vagal Nerve Stimulation in the Treatment of Drug-Resistant Epileptic Encephalopathies in Inborn Errors of Metabolism: Report of 2 Cases.

Patients affected by inborn errors of metabolism can develop catastrophic epilepsies ineligible for resective surgery. Few reports concerning vagal nerve stimulation in patients with epileptic encephalopathy in the context of metabolic diseases have been published in the literature. Drug-resistant epilepsies in metabolic disease could be a specific target for vagal nerve stimulation, although the efficacy of this technique in these patients still needs to be proved. The authors report our experience in treating refractory epilepsy with vagal nerve stimulation in 2 patients affected by inborn errors of metabolism. The first patient is a 23-year-old patient affected by glutaric aciduria type II, the other one is a 16-month-old child with nonketotic hyperglycinemia. Vagal nerve stimulation reduced seizures up to 50% in the first case and up to 90% in the second one.