Active site variants in STT3A cause a dominant type I congenital disorder of glycosylation with neuromusculoskeletal findings.

Congenital disorders of glycosylation (CDGs) form a group of rare diseases characterized by hypoglycosylation. We here report the identification of 16 individuals from nine families who have either inherited or de novo heterozygous missense variants in STT3A, leading to an autosomal-dominant CDG. STT3A encodes the catalytic subunit of the STT3A-containing oligosaccharyltransferase (OST) complex, essential for protein N-glycosylation. Affected individuals presented with variable skeletal anomalies, short stature, macrocephaly, and dysmorphic features; half had intellectual disability. Additional features included increased muscle tone and muscle cramps. Modeling of the variants in the 3D structure of the OST complex indicated that all variants are located in the catalytic site of STT3A, suggesting a direct mechanistic link to the transfer of oligosaccharides onto nascent glycoproteins. Indeed, expression of STT3A at mRNA and steady-state protein level in fibroblasts was normal, while glycosylation was abnormal. In S. cerevisiae, expression of STT3 containing variants homologous to those in affected individuals induced defective glycosylation of carboxypeptidase Y in a wild-type yeast strain and expression of the same mutants in the STT3 hypomorphic stt3-7 yeast strain worsened the already observed glycosylation defect. These data support a dominant pathomechanism underlying the glycosylation defect. Recessive mutations in STT3A have previously been described to lead to a CDG. We present here a dominant form of STT3A-CDG that, because of the presence of abnormal transferrin glycoforms, is unusual among dominant type I CDGs.

Gaucher disease prevalence in 600 patients affected by monoclonal gammopathy of undetermined significance.

BACKGROUND: Gaucher disease (GD) is a rare autosomal recessive inherited disorder caused by the lysosomal enzyme acid ß-glucosidase deficiency. Many patients experience a critical delay in the diagnosis of up to 8-10 years due to its rarity and variability in signs and symptoms, with the consultation of several specialists. PATIENTS AND METHODS: This prospective observational study analyzed the prevalence of GD in 600 patients with monoclonal gammopathy of uncertain significance (MGUS) from January 2018 until February 2022. RESULTS: The mean age of participants was 66 years, with a mean monoclonal component of 0.58 g/dL. In 433 MGUS patients with available data, anemia (hemoglobin level < 10 g/dL) was present in 31 patients (7%), and thrombocytopenia (platelet count <100.000/mm3 ) in 24 (5.5%). Of 600 MGUS patients tested for acid ß-glucosidase enzyme activity, 7 patients (1.2%) had activity below 2.5 nmol/h/mL. In comparison, GBA gene analysis was executed in 110 patients. It revealed 4 patients (0.7%) affected by GD (3 patients with compound heterozygous mutation and 1 with homozygous mutation), with a prevalence of 1 every 150 MGUS patients. Furthermore, 12 out of the remaining 106 evaluated patients (11%) were carriers of a single heterozygous mutation while having regular enzyme activity. CONCLUSIONS: The clinical heterogeneity of GD and frequent lack of awareness among physicians often lead to diagnostic delays and severe clinical manifestations. The role of MGUS in the presence of at least one clinical sign, such as low platelet count, organomegaly, bone pain, or bleeding tendency, could aid in initiating GD screening with DBS, thus reducing the period between symptom onset and the diagnosis of this rare disease.

ALG8-CDG: Molecular and phenotypic expansion suggests clinical management guidelines.

Congenital disorders of glycosylation are a continuously expanding group of monogenic disorders of glycoprotein and glycolipid glycan biosynthesis. These disorders mostly manifest with multisystem involvement. Individuals with ALG8-CDG commonly present with hypotonia, protein-losing enteropathy, and hepatic involvement. Here, we describe seven unreported individuals diagnosed with ALG8-CDG based on biochemical and molecular testing and we identify nine novel variants in ALG8, bringing the total to 26 individuals with ALG8-CDG in the medical literature. In addition to the typical multisystem involvement documented in ALG8-CDG, our cohort includes the two oldest patients reported and further expands the phenotype of ALG8-CDG to include stable intellectual disability, autism spectrum disorder and other neuropsychiatric symptoms. We further expand the clinical features in a variety of organ systems including ocular, musculoskeletal, dermatologic, endocrine, and cardiac abnormalities and suggest a comprehensive evaluation and monitoring strategy to improve clinical management.

HILIC-UPLC-MS for high throughput and isomeric N-glycan separation and characterization in Congenital Disorders Glycosylation and human diseases.

N-glycan analyses may serve uncovering disease-associated biomarkers, as well as for profiling distinctive changes supporting diagnosis of genetic disorders of glycan biosynthesis named congenital disorders of glycosylation (CDG). Strategies based on liquid chromatography (LC) preferentially coupled to electrospray ionization (ESI) - mass spectrometry (MS) have emerged as powerful analytical methods for N-glycan identification and characterization. To enhance detection sensitivity, glycans are commonly labelled with a functional tag prior to LC-MS analysis. Since most derivatization techniques are notoriously time-consuming, some commercial analytical kits have been developed to speed up N-deglycosylation and N-glycan labelling of glycoproteins of pharmaceutical and biological interest such as monoclonal antibodies (mAbs). We exploited the analytical capabilities of RapiFluor-MS (RFMS) to perform, by a slightly modified protocol, a detailed N-glycan characterization of total serum and single serum glycoproteins from specific patients with CDG (MAN1B1-CDG, ALG12-CDG, MOGS-CDG, TMEM199-CDG). This strategy, accomplished by Hydrophilic Interaction Chromatography (HILIC)-UPLC-ESI-MS separation of the RFMS derivatized N-glycans, allowed us to uncover structural details of patients serum released N-glycans, thus extending the current knowledge on glycan profiles in these individual glycosylation diseases. The applied methodology enabled to differentiate in some cases either structural isomers and isomers differing in the linkage type. All the here reported applications demonstrated that RFMS method, coupled to HILIC-UPLC-ESI-MS, represents a sensitive high throughput approach for serum N-glycome analysis and a valuable option for glycan detection and separation particularly for isomeric species.

Clinical and radiological correlates of activities of daily living in cerebellar atrophy caused by PMM2 mutations (PMM2-CDG).

We aimed to identify clinical, molecular and radiological correlates of activities of daily living (ADL) in patients with cerebellar atrophy caused by PMM2 mutations (PMM2-CDG), the most frequent congenital disorder of glycosylation. Twenty-six PMM2-CDG patients (12 males; mean age 13 ± 11.1 years) underwent a standardized assessment to measure ADL, ataxia (brief ataxia rating scale, BARS) and phenotype severity (Nijmegen CDG rating scale, NCRS). MRI biometry of the cerebellum and the brainstem were performed in 23 patients (11 males; aged 5 months-18 years) and 19 control subjects with equal gender and age distributions. The average total ADL score was 15.3 ± 8.5 (range 3-32 out of 36 indicating severe functional disability), representing variable functional outcome in PMM2-CDG patients. Total ADL scores were significantly correlated with NCRS (r2 = 0.55, p < 0.001) and BARS scores (r2 = 0.764; p < 0.001). Severe intellectual disability, peripheral neuropathy, and severe PMM2 variants were all significantly associated with worse functional outcome. Higher ADL scores were significantly associated with decreased diameters of cerebellar vermis (r2 = 0.347; p = 0.004), hemispheres (r2 = 0.436; p = 0.005), and brainstem, particularly the mid-pons (r2 = 0.64; p < 0.001) representing the major radiological predictor of functional disability score in multivariate regression analysis. We show that cerebellar syndrome severity, cognitive level, peripheral neuropathy, and genotype correlate with ADL used to quantify disease-related deficits in PMM2-CDG. Brainstem involvement should be regarded among functional outcome predictors in patients with cerebellar atrophy caused by PMM2-CDG.

International consensus guidelines for phosphoglucomutase 1 deficiency (PGM1-CDG): Diagnosis, follow-up, and management.

Phosphoglucomutase 1 (PGM1) deficiency is a rare genetic disorder that affects glycogen metabolism, glycolysis, and protein glycosylation. Previously known as GSD XIV, it was recently reclassified as a congenital disorder of glycosylation, PGM1-CDG. PGM1-CDG usually manifests as a multisystem disease. Most patients present as infants with cleft palate, liver function abnormalities and hypoglycemia, but some patients present in adulthood with isolated muscle involvement. Some patients develop life-threatening cardiomyopathy. Unlike most other CDG, PGM1-CDG has an effective treatment option, d-galactose, which has been shown to improve many of the patients' symptoms. Therefore, early diagnosis and initiation of treatment for PGM1-CDG patients are crucial decisions. In this article, our group of international experts suggests diagnostic, follow-up, and management guidelines for PGM1-CDG. These guidelines are based on the best available evidence-based data and experts' opinions aiming to provide a practical resource for health care providers to facilitate successful diagnosis and optimal management of PGM1-CDG patients.

Upgrading the evidence for the use of ambroxol in Gaucher disease and GBA related Parkinson: Investigator initiated registry based on real life data.

Ambroxol hydrochloride is an oral mucolytic drug available over-the-counter for many years as cough medicine. In 2009 it was identified as a pharmacological chaperone for mutant glucocerebrosidase, albeit in a several-fold higher dose. Unfortunately, there have been no pharma-driven clinical trials to establish its use. Thus, real-world observational data are needed on the safety and efficacy of ambroxol for patients with Gaucher disease (GD) and GBA-Parkinson disease (GBA-PD). Clinicians treating patients with ambroxol for GD and GBA-PD were approached to collaborate in an investigator-initiated registry. Anonymized data were collected, including demographics, GD type, GD-specific therapy (when applicable), adverse events (AEs), and, when available, efficacy data. We report the data of the first 41 patients (25 females) at a median (range) age 17 (1.5-74) from 13 centers; 11 with GD type 1(four diagnosed with PD), 27 with neuronopathic GD (nGD), and three GBA mutation carriers with PD. The median (range) treatment period and maximum dose of ambroxol were 19 (1-76) months and 435 (75-1485) mg/day, respectively. One patient with type 2 GD died of her disease. No other severe AEs were reported. Twelve patients experienced AE, including minor bowel discomfort, cough, allergic reaction, mild proteinuria, dizziness and disease progression. Clinical benefits were reported in 25 patients, including stable or improved neurological status, increased physical activity, and reduced fatigue. Until the approval of specific therapies for nGD and disease-modification for GBA-PD, these preliminary data may be encouraging to physicians and patients who consider an off-label use of ambroxol.

Further delineation and long-term evolution of electroclinical phenotype in Mowat Wilson Syndrome. A longitudinal study in 40 individuals.

BACKGROUND: Epilepsy is a main feature of Mowat Wilson Syndrome (MWS), a congenital malformation syndrome caused by ZEB2 variants. The aim of this study was to investigate the long-term evolution of the electroclinical phenotype of MWS in a large population. METHODS: Forty-individuals with a genetically confirmed diagnosis were enrolled. Three age groups were identified (t1 = 0-4; t2 = 5-12; t3 = >13 years); clinical data and EEG records were collected, analyzed, and compared for age group. Video-EEG recorded seizures were reviewed. RESULTS: Thirty-six of 40 individuals had epilepsy, of whom 35/35 aged >5 years. Almost all (35/36) presented focal seizures at onset (mean age at onset 3.4 ±â€¯2.3 SD) that persisted, reduced in frequency, in 7/22 individuals after the age of 13. Absences occurred in 22/36 (mean age at onset 7.2 ±â€¯0.9 SD); no one had absences before 6 and over 16 years old. Paroxysmal interictal abnormalities in sleep also followed an age-dependent evolution with a significant increase in frequency at school age (p = 0.002) and a reduction during adolescence (p = 0.008). Electrical Status Epilepticus during Sleep occurred in 14/36 (13/14 aged 5-13 years old at onset). Seven focal seizure ictal video-EEGs were collected: all were long-lasting and more visible clinical signs were often preceded by prolonged electrical and/or subtle (erratic head and eye orientation) seizures. Valproic acid was confirmed as the most widely used and effective drug, followed by levetiracetam. CONCLUSIONS: Epilepsy is a major sign of MWS with a characteristic, age-dependent, electroclinical pattern. Improvement with adolescence/adulthood is usually observed. Our data strengthen the hypothesis of a GABAergic transmission imbalance underlying ZEB2-related epilepsy.

Accurate Molecular Diagnosis of Gaucher Disease Using Clinical Exome Sequencing as a First-Tier Test.

Gaucher disease (GD) is an autosomal recessive lysosomal disorder due to beta-glucosidase gene (GBA) mutations. The molecular diagnosis of GD is complicated by the presence of recombinant alleles originating from a highly homologous pseudogene. Clinical exome sequencing (CES) is a rapid genetic approach for identifying disease-causing mutations. However, copy number variation and recombination events are poorly detected, and further investigations are required to avoid mis-genotyping. The aim of this work was to set-up an integrated strategy for GD patients genotyping using CES as a first-line test. Eight patients diagnosed with GD were analyzed by CES. Five patients were fully genotyped, while three were revealed to be homozygous for mutations that were not confirmed in the parents. Therefore, MLPA (multiplex ligation-dependent probe amplification) and specific long-range PCR were performed, and two recombinant alleles, one of them novel, and one large deletion were identified. Furthermore, an MLPA assay performed in one family resulted in the identification of an additional novel mutation (p.M124V) in a relative, in trans with the known p.N409S mutation. In conclusion, even though CES has become extensively used in clinical practice, our study emphasizes the importance of a comprehensive molecular strategy to provide proper GBA genotyping and genetic counseling.

Genotype-phenotype variable correlation in Wilson disease: clinical history of two sisters with the similar genotype.

BACKGROUND: Wilson disease (WD) is an Autosomal-Recessive disorder due to mutations of ATP7B gene on chromosome 13q14.3. Inadequate protein function leads to low ceruloplasmin blood levels and copper accumulation in liver, basal ganglia and chornea. Main clinical manifestations are hypertransaminasemia, tremors, dysarthria, dystonia and psychiatric symptoms. The phenotypic variability in WD is considerable and its onset can be heterogeneous: the most common type in childhood is the hepatic involvement, followed by the neurological one or others. The presence of a genotype-phenotype correlation has not yet been fully demonstrated. The phenotypic variability may be explained by the intervention of other modifier genes regulating copper metabolism in the presence of mutations ATP7B. CASE PRESENTATION: A streaking phenotypic variability was observed in two Sicilian sisters carrying the same genotype for ATB7B gene [c.3207C > A / c.3904-2A > G]. Although both started to present signs at age 10 years, onset was characterized by neurological signs in the first (tremors, motor incoordination, language and cognitive impairment), while liver involvement has been the only sign in the other. They started the same chelation therapy. After a 20-year follow-up the former is severely affected (MRI evidence of basal ganglia copper deposits and hyperchogenic liver, thrombocytopenia), while the latter presents only a moderate liver enlargement. In literature, the splice mutation c.3904-2A > G is also reported in Egypt population, associated with acute liver failure or chronic hepatic disease, and it could be typical of Mediterranean area, not being reported in other geographical zones. CONCLUSION: Based on our clinical experience in Eastern Sicily, there is a considerable phenotypic variability in WD, even in the presence of an identical genotype. The mutation c.3904-2A > G could be associated with this phenotypic variability in Mediterranean population, but further studies should be conducted. This condition could be explained by the intervention of modifier genes regulating copper metabolism in the presence of defective ATP7B protein function. Further investigations on their role by Next Generation Sequencing or Whole Exome Analysis might have a profound impact on patients' management and in particular on therapy.

A new strategy implementing mass spectrometry in the diagnosis of congenital disorders of N-glycosylation (CDG).

Objectives: Congenital disorders of N-glycosylation (CDG) are a large group of rare metabolic disorders caused by defects in the most common post-translational modification of proteins. CDGs are often difficult to diagnose as they are manifested with non-specific symptoms and signs. Analysis of serum transferrin (TRF) isoforms, as the classical procedure used to identify a CDG patient, enables to predict pathological steps in the N-linked glycosylation process. Methods: We devised a new strategy based on liquid chromatography-mass spectrometry (LC-MS) for the analysis of TRF isoforms by combining a simple and fast sample preparation with a specific chromatographic cleanup/separation step followed by mass-spectrometric measurement. Single TRF isoform masses were obtained through reconstruction of multiply charged electrospray data collected by quadrupole-MS technology. Hereby, we report the first analyzed serum samples obtained from 20 CDG patients and 100 controls. Results: The ratio of desialylated isoforms to total TRF was calculated for patients and controls. CDG-Type I patients showed higher amounts of bi-sialo isoform (range: 6.7-29.6%) compared to controls (<5.5%, mean percentage 3.9%). CDG-Type II pattern showed an increased peak of tri-sialo isoforms. The mean percentage of tri-sialo-TRF was 9.3% (range: 2.9-12.9%) in controls, which was lower than that obtained from two patients with COG5-CDG and MAN1B1-CDG (18.5 and 24.5%). Intraday and between-day imprecisions were less than 9 and 16%, respectively, for bi-sialo- and less than 3 and 6% for tri-sialo-TRF. Conclusions: This LC-MS-based approach provides a simple, sensitive and fast analytical tool for characterizing CDG disorders in a routine clinical biochemistry while improving diagnostic accuracy and speeding clinical decision-making.

ALG12-CDG: novel glycophenotype insights endorse the molecular defect.

Congenital disorders of glycosylation (CDG) are genetic diseases characterized by deficient synthesis (CDG type I) and/or abnormal processing (CDG type II) of glycan moieties linked to protein and lipids. The impact of the molecular defects on protein glycosylation and in turn on the clinical phenotypes of patients with CDG is not yet understood. ALG12-CDG is due to deficiency of ALG12 α1,6-mannosyltransferase that adds the eighth mannose residue on the dolichol-PP-oligosaccharide precursor in the endoplasmic reticulum. ALG12-CDG is a severe multisystem disease associated with low to deficient serum immunoglobulins and recurrent infections. We thoroughly investigated the glycophenotype in a patient with novel ALG12 variants and immunodeficiency. We analyzed serum native transferrin, as first line test for CDG and we profiled serum IgG and total serum N-glycans by a combination of consolidated (N-glycan analysis by MALDI MS) and innovative mass spectrometry-based protocols, such as GlycoWorks RapiFluor N-glycan analysis coupled with LC-ESI MS. Intact serum transferrin showed, as expected for a CDG type I defect, underoccupancy of N-glycosylation sites. Surprisingly, total serum proteins and IgG N-glycans showed some specific changes, consisting in accumulating amounts of definite high-mannose and hybrid structures. As a whole, ALG12-CDG behaves as a dual CDG (CDG-I and II defects) and it is associated with distinct, abnormal glycosylation of total serum and IgG N-glycans. Glycan profiling of target glycoproteins may endorse the molecular defect unraveling the complex clinical phenotype of CDG patients.

International clinical guidelines for the management of phosphomannomutase 2-congenital disorders of glycosylation: Diagnosis, treatment and follow up.

Phosphomannomutase 2 (PMM2-CDG) is the most common congenital disorder of N-glycosylation and is caused by a deficient PMM2 activity. The clinical presentation and the onset of PMM2-CDG vary among affected individuals ranging from a severe antenatal presentation with multisystem involvement to mild adulthood presentation limited to minor neurological involvement. Management of affected patients requires a multidisciplinary approach. In this article, a systematic review of the literature on PMM2-CDG was conducted by a group of international experts in different aspects of CDG. Our managment guidelines were initiated based on the available evidence-based data and experts' opinions. This guideline mainly addresses the clinical evaluation of each system/organ involved in PMM2-CDG, and the recommended management approach. It is the first systematic review of current practices in PMM2-CDG and the first guidelines aiming at establishing a practical approach to the recognition, diagnosis and management of PMM2-CDG patients.

Optic Neuropathy, Secondary to Ethmoiditis, and Onodi Cell Inflammation during Childhood: A Case Report and Review of the Literature.

Optic neuropathy consists of several etiological events. The primary etiologies of its acute form include optic neuritis, ischemic optic neuropathy, inflammatory (nondemyelinating) disorders, and trauma. Its subacute and chronic forms are most often linked to compressive, toxic, nutritional, or hereditary-genetic causes. Visual loss, dyschromatopsia, and visual field defects are the presenting symptoms. The Onodi cell (sphenoethmoidal air cell) is an anatomic variant located laterally and superior to the sphenoid sinus; it is closely related to the optic nerve. Onodi cell disorders are rare and may be unnoticed in differential diagnoses of patients with ocular and neurological manifestations. Here, we present the case of a 12-year-old boy with headache and acute loss of sight characterized by hemianopsia in the left eye and retrobulbar optic neuropathy caused by left sphenoethmoidal sinusitis with the presence of Onodi cell inflammation. The diagnosis was confirmed by multilayered paranasal computed tomography and cerebral magnetic resonance imaging. Therapeutic treatment resulted in gradual improvement: at the 2-week follow-up, the patient no longer had headaches and his visual acuity returned to normal. Inflammation of Onodi cells should be considered in children with headache and abnormal vision.

Arterial ischemic stroke (AIS) in childhood: clinical report from a single control center.

INTRODUCTION: Stroke is the clinical designation for a rapidly developing loss of brain function due to an interruption in the blood supply to all or part of the brain. It is the third cause of death in adults and one of the top 10 causes in pediatric age. The perinatal period of onset is the second only to adult age group in the incidence of stroke. Arterial ischemic stroke during childhood occurs most frequently in the perinatal period with an incidence of 1 out 2300-5000 live infant births. MATERIALS AND METHODS: This is a retrospective study that includes 28 patients affected by perinatal arterial ischemic stroke. Family and gestational history, risk factors of perinatal stroke, gender and clinical data of affected children and outcome are reported. RESULTS: A stroke family history was registered in three unrelated families. Gestational history disclosed cases of threats of abortion, preterm delivery, hyperthermia, gestosis, and placental disorders. In the children, onset of seizures were reported within 3 days of life and diagnosis of stroke was confirmed by brain MRI which disclosed involvement of the middle cerebral artery in all the cases. Hemilateral cerebral palsy, epileptic seizures, and intellectual disability from mild to severe were the most frequent complications. CONCLUSION: Stroke is still a common and dreadful events in perinatal period as this disorder is often unpredictable and cause of severe neurological impairment.

Phenotype and genotype of 87 patients with Mowat-Wilson syndrome and recommendations for care.

PURPOSE: Mowat-Wilson syndrome (MWS) is a rare intellectual disability/multiple congenital anomalies syndrome caused by heterozygous mutation of the ZEB2 gene. It is generally underestimated because its rarity and phenotypic variability sometimes make it difficult to recognize. Here, we aimed to better delineate the phenotype, natural history, and genotype-phenotype correlations of MWS. METHODS: In a collaborative study, we analyzed clinical data for 87 patients with molecularly confirmed diagnosis. We described the prevalence of all clinical aspects, including attainment of neurodevelopmental milestones, and compared the data with the various types of underlying ZEB2 pathogenic variations. RESULTS: All anthropometric, somatic, and behavioral features reported here outline a variable but highly consistent phenotype. By presenting the most comprehensive evaluation of MWS to date, we define its clinical evolution occurring with age and derive suggestions for patient management. Furthermore, we observe that its severity correlates with the kind of ZEB2 variation involved, ranging from ZEB2 locus deletions, associated with severe phenotypes, to rare nonmissense intragenic mutations predicted to preserve some ZEB2 protein functionality, accompanying milder clinical presentations. CONCLUSION: Knowledge of the phenotypic spectrum of MWS and its correlation with the genotype will improve its detection rate and the prediction of its features, thus improving patient care.

Composition and structure of glycosaminoglycans in DBS from 2-3-day-old newborns for the diagnosis of mucopolysaccharidosis.

Dried blood spot (DBS) technology is a cheap and easy method largely applied in newborn screening. Mucopolysaccharidoses (MPS) are characterized by the deficit of enzymes that degrade glycosaminoglycans (GAGs) characterized by progressive worsening of the conditions. For a possible early diagnosis of MPS, we developed a method of uronic acid (UA)-GAGs determination in DBS of 600 healthy newborns and from a small group of MPS subjects matched for age. Spotted blood UA-GAGs of the normal newborns are composed of 67.2% chondroitin sulfate (CS), 28.6% heparan sulfate (HS) and 4.4% hyaluronic acid with a CS/HS ratio of 2.35 and a total GAGs content of 0.43 µg/DBS. A chemical evaluation of CS and HS structure was performed by measuring their disaccharide composition, sulfation and the overall charge density. The DBS of four different MPS types presented an increase of total or single UA-GAGs content and/or modifications of the CS and HS disaccharide composition as well as chemical signature also related to the MPS enzymatic defect. The modifications of the UA-GAGs composition, parameters and structure of healthy newborns determined in DBS would be useful for a possible early diagnosis of various MPS types.

Hypoglossal nerve paralysis in a child after a dental procedure.

Unilateral palsy of the hypoglossal nerve is a rare complication of orthodontic procedures. The main reported causes of HNP are: orthopedic and otorhinolaryngology surgical interventions, and in particular maneuvers involving compression or overstretching of the hypoglossal nerve, dental procedures and traumas, and also infections, motoneuron disorders, tumors, vascular diseases. Diagnosis is usually performed by electrophysiology studies (EMG-VCN), and brain magnetic resonance imaging (MRI) is useful to exclude other causes. The prognosis depends on the location and extension of the damage. Currently there is not a standardized treatment approach except the speech therapy, although, in some cases, the high-dose steroid treatment could be useful. We describe the case of a ten-year-old female, who was admitted in our Unit after a deviation of the tongue associated with dysarthria and dysphagia, occurred after the application of a mobile orthodontic device.

ALG1-CDG: Clinical and Molecular Characterization of 39 Unreported Patients.

Congenital disorders of glycosylation (CDG) arise from pathogenic mutations in over 100 genes leading to impaired protein or lipid glycosylation. ALG1 encodes a ß1,4 mannosyltransferase that catalyzes the addition of the first of nine mannose moieties to form a dolichol-lipid linked oligosaccharide intermediate required for proper N-linked glycosylation. ALG1 mutations cause a rare autosomal recessive disorder termed ALG1-CDG. To date 13 mutations in 18 patients from 14 families have been described with varying degrees of clinical severity. We identified and characterized 39 previously unreported cases of ALG1-CDG from 32 families and add 26 new mutations. Pathogenicity of each mutation was confirmed based on its inability to rescue impaired growth or hypoglycosylation of a standard biomarker in an alg1-deficient yeast strain. Using this approach we could not establish a rank order comparison of biomarker glycosylation and patient phenotype, but we identified mutations with a lethal outcome in the first two years of life. The recently identified protein-linked xeno-tetrasaccharide biomarker, NeuAc-Gal-GlcNAc2 , was seen in all 27 patients tested. Our study triples the number of known patients and expands the molecular and clinical correlates of this disorder.

Optimizing the molecular diagnosis of GALNS: novel methods to define and characterize Morquio-A syndrome-associated mutations.

Morquio A syndrome (MPS IVA) is a systemic lysosomal storage disorder caused by the deficiency of N-acetylgalactosamine-6-sulfatase (GALNS), encoded by the GALNS gene. We studied 37 MPS IV A patients and defined genotype-phenotype correlations based on clinical data, biochemical assays, molecular analyses, and in silico structural analyses of associated mutations. We found that standard sequencing procedures, albeit identifying 14 novel small GALNS genetic lesions, failed to characterize the second disease-causing mutation in the 16% of the patients' cohort. To address this drawback and uncover potential gross GALNS rearrangements, we developed molecular procedures (CNV [copy-number variation] assays, QF-PCRs [quantitative fluorescent-PCRs]), endorsed by CGH-arrays. Using this approach, we characterized two new large deletions and their corresponding breakpoints. Both deletions were heterozygous and included the first exon of the PIEZO1 gene, which is associated with dehydrated hereditary stomatocitosis, an autosomal-dominant syndrome. In addition, we characterized the new GALNS intronic lesion c.245-11C>G causing m-RNA defects, although identified outside the GT/AG splice pair. We estimated the occurrence of the disease in the Italian population to be approximately 1:300,000 live births and defined a molecular testing algorithm designed to help diagnosing MPS IVA and foreseeing disease progression.