Depression, anxiety, self-efficacy, and self-esteem in high-risk pregnancy

BACKGROUND

The aim of the study was to evaluate the levels of depression, state and trait anxiety, self-efficacy, and self-esteem among women with high-risk pregnancy due to previous adverse pregnancy outcomes (PAPOs) or prepregnancy diseases (PPD), before and after delivery, compared to controls.

METHODS

An observational longitudinal study on psychological dimensions was conducted on 86 women attending a university referral center for high-risk pregnancy, by administering the Edinburgh Postnatal Depression Scale, the State and Trait Anxiety Inventory, the General Self-Efficacy Scale, and the Self-esteem Scale. A pretest (in the third trimester of pregnancy) and a follow-up measurement session (one month after the delivery) were applied. PAPOs group, PPD group and controls were compared.

RESULTS

The PAPOs group had higher levels of depression compared to the other groups, with above-threshold levels. However, a more relevant decrease in depression was found in the PAPOs group after delivery. Levels of self-efficacy and self-esteem were unexpectedly high during and after pregnancy in all the groups.

CONCLUSIONS

A PAPO represents a risk factor for depression development during pregnancy, whereas a PPD seems to be less relevant in influencing affective dimensions. Surprisingly, all pregnant women, independently of the obstetric risk, showed high levels of self-efficacy and self-esteem.

Transition to glycerol phenylbutyrate for the management of urea cycle disorders: clinical experiences

BACKGROUND

Urea cycle disorders (UCDs) are a group of rare inborn diseases caused by a deficiency in one of the six enzymes or one of the two transporters involved in the urea cycle. The most common biochemical feature is elevated blood ammonia levels, which can be toxic at high levels, especially to the brain and may manifest as encephalopathy if left untreated. Glycerol phenylbutyrate (GPB) is currently approved for use in the USA and Europe for patients of all ages with UCD who cannot be managed with protein restriction and/or amino acid supplementation alone. This article presents the author's experience in different exemplary settings and depicts the most efficient management of UCDs with GPB.

CASE PRESENTATION

Six patient histories are described. 4 had OCT, one citrullinemia, and one argininosuccinic aciduria. Treatment with GPB was started between 2 days and 14 years of age. Before GPB, one patient had not been treated, 4 had received sodium phenylbutyrate (NaPB), and one Na benzoate.

CONCLUSIONS

Overall, treatment with GPB was followed by a relevant metabolic improvement, resulting in better therapeutic compliance, reduced hospitalization, and improved quality of life.

Clinical profile and outcome of cardiomyopathies in infants and children seen at a tertiary centre

INTRODUCTION

Due to their rare prevalence and marked heterogeneity, pediatric cardiomyopathies (CMPs) are little known and scarcely reported. We report the etiology, clinical profile and outcome of a consecutive cohort of children diagnosed with CMP and followed at Meyer Children's Hospital over a decade.

PATIENTS AND METHODS

We retrospectively reviewed patients consecutively referred from May 2008 to May 2019 for pediatric onset CMP (<18 years). Heart disease caused by arrhythmic disorders, toxic agents, rheumatic conditions and maternal disease were excluded.

RESULTS

We enrolled 110 patients (65 males), diagnosed at a median age of 27 [4-134] months; 35% had an infant onset (<1 year of age). A positive family history was more often associated with childhood-onset (38.8%). Hypertrophic cardiomyopathy (HCM; 48 patients) was the most frequent phenotype, followed by dilated cardiomyopathy (DCM; 35 patients). While metabolic and idiopathic etiologies were preponderant in infants, metabolic and sarcomeric diseases were most frequent in the childhood-onset group. Major adverse cardiac events (MACE) occurred in 31.8% of patients, including hospitalization for acute heart failure in 25.5% of patients, most commonly due to DCM. Overall, the most severe outcomes were documented in patients with metabolic diseases.

CONCLUSIONS

In a consecutive cohort of pediatric patients with CMP, those with infantile onset and with a metabolic etiology had the worst prognosis. Overall, MACE occurred in 41% of the entire population, most commonly associated with DCM, inborn errors of metabolism and genetic syndromes. Systematic NGS genetic testing was critical for etiological diagnosis and management.

3-Hydroxyisobutyric acid dehydrogenase deficiency: Expanding the clinical spectrum and quantitation of D- and L-3-Hydroxyisobutyric acid by an LC-MS/MS method

A deficiency of 3-hydroxyisobutyric acid dehydrogenase (HIBADH) has been recently identified as a cause of primary 3-hydroxyisobutyric aciduria in two siblings; the only previously recognized primary cause had been a deficiency of methylmalonic semialdehyde dehydrogenase, the enzyme that is immediately downstream of HIBADH in the valine catabolic pathway and is encoded by the ALDH6A1 gene. Here we report on three additional patients from two unrelated families who present with marked and persistent elevations of urine L-3-hydroxyisobutyric acid (L-3HIBA) and a range of clinical findings. Molecular genetic analyses revealed novel, homozygous variants in the HIBADH gene that are private within each family. Evidence for pathogenicity of the identified variants is presented, including enzymatic deficiency of HIBADH in patient fibroblasts. This report describes new variants in HIBADH as an underlying cause of primary 3-hydroxyisobutyric aciduria and expands the clinical spectrum of this recently identified inborn error of valine metabolism. Additionally, we describe a quantitative method for the measurement of D- and L-3HIBA in plasma and urine and present the results of a valine restriction therapy in one of the patients.

Case Report: Zellweger Syndrome and Humoral Immunodeficiency: The Relevance of Newborn Screening for Primary Immunodeficiency

BACKGROUND

Zellweger syndrome (ZS) is a congenital autosomal recessive disease within the spectrum of peroxisome biogenesis disorders, characterized by the impairment of peroxisome assembly. The presence of peroxisome enzyme deficiencies leads to complex developmental sequelae, progressive disabilities, and multiorgan damage, due to intracellular accumulation of very-long-chain fatty acids (VLCFAs).

CASE PRESENTATION

We report the case of an infant affected by ZS in which agammaglobulinemia, detected through neonatal screening of congenital immunodeficiencies, appeared as a peculiar trait standing out among all the other classical characteristics of the syndrome. The exome analysis through next-generation sequencing (NGS), which had previously confirmed the diagnostic suspicion of ZS, was repeated, but no mutations causative of inborn error of immunity (humoral defect) were detected.

CONCLUSION

In this case, no genetic variants accountable for the abovementioned agammaglobulinemia were detected. Given that the scientific literature reports the involvement of peroxisomes in the activation of Nuclear Factor κ-light-chain-enhancer of activated B cells (NF-κB) pathway, which is crucial for B-cell survival, with this work, we hypothesize the existence of a link between ZS and humoral immunodeficiencies. Further studies are required to confirm this hypothesis.

The Early Elementary School Abbreviated Math Anxiety Scale (the EES-AMAS): A New Adapted Version of the AMAS to Measure Math Anxiety in Young Children

In the past decade, there has been increasing interest in understanding how and when math anxiety (MA) develops. The incidence and effects of MA in primary school children, and its relations with math achievement, have been investigated. Nevertheless, only a few studies have focused on the first years of primary school, highlighting that initial signs of MA may emerge as early as 6 years of age. Nevertheless, there are some issues with measuring MA in young children. One of these is that, although several scales have been recently developed for this age group, the psychometric properties of most of these instruments have not been adequately tested. There is also no agreement in the number and identity of the factors that underlie MA at this young age. Some scales also consist of several items, which make them impractical to use in multivariate studies, which aim at the simultaneous measurement of several constructs. Finally, most scales have been developed and validated in US populations, and it is unclear if they are appropriate to be used in other countries. In order to address these issues, the current studies aimed at developing a short, new instrument to assess MA in early elementary school students, the Early Elementary School Abbreviated Math Anxiety Scale (the EES-AMAS). This scale is an adapted version of the Abbreviated Math Anxiety Scale (AMAS; Hopko et al., 2003), which is one of the most commonly used scales to measure MA and has been shown to be a valid and reliable measure across a number of countries and age groups. The psychometric properties of the new scale have been investigated by taking into account its dimensionality, reliability, and validity. Moreover, the gender invariance of the scale has been verified by showing the measurement equivalence of the scale when administered to male and female pupils. We have also demonstrated the equivalence of the scale across languages (Italian and English). Overall, the findings confirmed the validity and reliability of the new scale in assessing the early signs of math anxiety and in measuring differences between genders and educational contexts. We have also shown that MA was already related to math performance, and teacher’s ratings of children’s math ability at this young age. Additionally, we have found no gender differences in MA in our samples of 6- and 7-year-old children, an important finding, given the strong evidence for gender differences in MA in older age groups.

Mutations in ELAC2 associated with hypertrophic cardiomyopathy impair mitochondrial tRNA 3'-end processing

Mutations in either the mitochondrial or nuclear genomes are associated with a diverse group of human disorders characterized by impaired mitochondrial respiration. Within this group, an increasing number of mutations have been identified in nuclear genes involved in mitochondrial RNA metabolism, including ELAC2. The ELAC2 gene codes for the mitochondrial RNase Z, responsible for endonucleolytic cleavage of the 3' ends of mitochondrial pre-tRNAs. Here, we report the identification of 16 novel ELAC2 variants in individuals presenting with mitochondrial respiratory chain deficiency, hypertrophic cardiomyopathy (HCM), and lactic acidosis. We provide evidence for the pathogenicity of the novel missense variants by studying the RNase Z activity in an in vitro system. We also modeled the residues affected by a missense mutation in solved RNase Z structures, providing insight into enzyme structure and function. Finally, we show that primary fibroblasts from the affected individuals have elevated levels of unprocessed mitochondrial RNA precursors. Our study thus broadly confirms the correlation of ELAC2 variants with severe infantile-onset forms of HCM and mitochondrial respiratory chain dysfunction. One rare missense variant associated with the occurrence of prostate cancer (p.Arg781His) impairs the mitochondrial RNase Z activity of ELAC2, suggesting a functional link between tumorigenesis and mitochondrial RNA metabolism.

SLC25A10 biallelic mutations in intractable epileptic encephalopathy with complex I deficiency

Mitochondrial diseases are a plethora of inherited neuromuscular disorders sharing defects in mitochondrial respiration, but largely different from one another for genetic basis and pathogenic mechanism. Whole exome sequencing was performed in a familiar trio (trio-WES) with a child affected by severe epileptic encephalopathy associated with respiratory complex I deficiency and mitochondrial DNA depletion in skeletal muscle. By trio-WES we identified biallelic mutations in SLC25A10, a nuclear gene encoding a member of the mitochondrial carrier family. Genetic and functional analyses conducted on patient fibroblasts showed that SLC25A10 mutations are associated with reduction in RNA quantity and aberrant RNA splicing, and to absence of SLC25A10 protein and its transporting function. The yeast SLC25A10 ortholog knockout strain showed defects in mitochondrial respiration and mitochondrial DNA content, similarly to what observed in the patient skeletal muscle, and growth susceptibility to oxidative stress. Albeit patient fibroblasts were depleted in the main antioxidant molecules NADPH and glutathione, transport assays demonstrated that SLC25A10 is unable to transport glutathione. Here, we report the first recessive mutations of SLC25A10 associated to an inherited severe mitochondrial neurodegenerative disorder. We propose that SLC25A10 loss-of-function causes pathological disarrangements in respiratory-demanding conditions and oxidative stress vulnerability.

Autophagic vacuolar myopathy caused by a CLN3 mutation. A case report

We present a 29-year-old man with visual failure since childhood, muscle weakness, subtle heart muscle hypertrophy, and seizures who was initially considered to be affected by a mitochondrial encephalomyopathy because of the multiple unspecific involvement of brain, muscle and retinal tissues. Only the muscle biopsy findings correctly guided the genetic investigations and the identification of an autophagic vacuolar myopathy due to a homozygous mutation in CLN3. We believe that information in autophagic muscle disorders should further alert clinicians to consider CLN3 in individuals with vacuolar myopathy, especially if they have visual and cardiac involvement.

Optical coherence tomography morphology and evolution in cblC disease-related maculopathy in a case series of very young patients

PURPOSE

To describe the retinal structure of a group of patients affected by methylmalonic aciduria with homocystinuria cblC type, caused by mutations in the MMACHC gene, using spectral domain optical coherence tomography (SD-OCT).

METHODS

Young patients (n = 11, age 0-74 months) with cblC disease, detected by newborn screening or clinically diagnosed within 40 days of life, underwent molecular analysis and complete ophthalmic examination, including fundus photography and SD-OCT. In one case, we also performed fluorescein angiography (FA) and standard electroretinography (ERG).

RESULTS

Molecular analysis of the MMACHC gene fully confirmed cblC disease in nine of 11 patients. Two patients harboured only a single heterozygous pathogenic MMACHC mutation and large unbalanced rearrangements were excluded by array-CGH analysis in both. All patients except two showed a bilateral maculopathy. In general, retinal changes were first observed before one year of age and progressed to a well-established maculopathy. Measurable visual acuities ranged from normal vision, in keeping with age, to bilateral, severe impairment of central vision. Nystagmus was present in six patients. Spectral domain optical coherence tomography (SD-OCT) showed macular thinning with severe alterations in outer, and partial sparing of inner, retinal layers.

CONCLUSION

Patients affected by cblC disease may frequently show an early onset maculopathy with variable ophthalmoscopic appearance. Spectral domain optical coherence tomography (SD-OCT) broadens the knowledge of subtle retinal alterations during the disease's progression and helps to shed light on the pathological mechanism of maculopathy development.

Recurrent De Novo and Biallelic Variation of ATAD3A, Encoding a Mitochondrial Membrane Protein, Results in Distinct Neurological Syndromes

ATPase family AAA-domain containing protein 3A (ATAD3A) is a nuclear-encoded mitochondrial membrane protein implicated in mitochondrial dynamics, nucleoid organization, protein translation, cell growth, and cholesterol metabolism. We identified a recurrent de novo ATAD3A c.1582C>T (p.Arg528Trp) variant by whole-exome sequencing (WES) in five unrelated individuals with a core phenotype of global developmental delay, hypotonia, optic atrophy, axonal neuropathy, and hypertrophic cardiomyopathy. We also describe two families with biallelic variants in ATAD3A, including a homozygous variant in two siblings, and biallelic ATAD3A deletions mediated by nonallelic homologous recombination (NAHR) between ATAD3A and gene family members ATAD3B and ATAD3C. Tissue-specific overexpression of bor^R534W, the Drosophila mutation homologous to the human c.1582C>T (p.Arg528Trp) variant, resulted in a dramatic decrease in mitochondrial content, aberrant mitochondrial morphology, and increased autophagy. Homozygous null bor larvae showed a significant decrease of mitochondria, while overexpression of bor^WT resulted in larger, elongated mitochondria. Finally, fibroblasts of an affected individual exhibited increased mitophagy. We conclude that the p.Arg528Trp variant functions through a dominant-negative mechanism that results in small mitochondria that trigger mitophagy, resulting in a reduction in mitochondrial content. ATAD3A variation represents an additional link between mitochondrial dynamics and recognizable neurological syndromes, as seen with MFN2, OPA1, DNM1L, and STAT2 mutations.

Common and Novel TMEM70 Mutations in a Cohort of Italian Patients with Mitochondrial Encephalocardiomyopathy

ATP synthase or complex V (cV) of the oxidative phosphorylation system is responsible for the production of ATP, dissipating the electrochemical gradient generated by the mitochondrial respiratory chain. In addition to maternally transmitted cV dysfunction caused by mutations in mtDNA genes (MT-ATP6 or MT-ATP8), encoding cV subunits, recessive mutations in the nuclear TMEM70 are the most frequent cause of ATP synthase deficiency.We report on a cohort of ten Italian patients presenting with neonatal lactic acidosis, respiratory distress, hypotonia, cardiomyopathy and psychomotor delay and harbouring mutations in TMEM70, including the common splice mutation and four novel variants. TMEM70 protein was virtually absent in all tested TMEM70 patients' specimens.The exact function of TMEM70 is not known, but it is considered to impact on cV assembly since TMEM70 mutations have been associated with isolated cV activity reduction. We detected a clear cV biochemical defect in TMEM70 patients' fibroblasts, whereas the assay was not reliable in frozen muscle. Nevertheless, the evaluation of the amount of holocomplexes in patients with TMEM70 mutations showed a nearly absent cV in muscles and a strong decrease of cV with accumulation of sub-assembly species in fibroblasts. In our cohort we found not only cV deficiencies but also impairment of other OXPHOS complexes. By ultrastructural analysis of muscle tissue from one patient with isolated cV deficiency, we found a severely impaired mitochondrial morphology with loss of the cristae. These findings indicate that cV impairment could indirectly alter other respiratory chain complex activities by disrupting the mitochondrial cristae structure.

Morquio A syndrome due to maternal uniparental isodisomy of the telomeric end of chromosome 16

Morquio A syndrome (MPS IVA) is a recessive lysosomal storage disorder (LSD) caused by mutations in the GALNS gene leading to the deficiency of lysosomal enzyme N-acetylgalactosamine-6-sulfate sulfatase (GALNS). Patients show a broad spectrum of phenotypes ranging from classical severe type to mild forms. Classical forms are characterized by severe bone dysplasia and usually normal intelligence. So far, more than 170 unique mutations have been identified in the GALNS gene of MPS IVA patients. We report on a Morquio A patient with a classical phenotype who was found to be homozygous for a missense mutation (c.236 G>A; p.Cys79Tyr) in the GALNS gene. This alteration affects the highly conserved p.Cys79 that is transformed into formylglycine, the catalytic residue of the active site. The mutation was present in the proband's mother, but not in the father, whose paternity was confirmed by microsatellite analysis. In order to test the hypothesis of maternal uniparental disomy (UPD), we investigated the segregation of sixteen microsatellite markers from chromosome 16. The results showed a condition of maternal UPD due to an error in meiosis I. Maternal isodisomy of the 16q24 region led to homozygosity for the GALNS mutant allele, causing the patient's disease. These findings allow to add for the first time the LSD Morquio A syndrome to the list of conditions that can be caused by UPD. The possibility of UPD is relevant when giving genetic counseling to couples since the recurrent risk in future pregnancies is dramatically reduced.

Carbamoyl phosphate synthetase 1 deficiency in Italy: clinical and genetic findings in a heterogeneous cohort

Carbamoyl Phosphate Synthetase 1 deficiency (CPS1D) is a rare autosomal recessive urea cycle disorder, potentially leading to lethal hyperammonemia. Based on the age of onset, there are two distinct phenotypes: neonatal and late form. The CPS1 enzyme, located in the mitochondrial matrix of hepatocytes and epithelial cells of intestinal mucosa, is encoded by the CPS1 gene. At present more than 220 clear-cut genetic lesions leading to CPS1D have been reported. As most of them are private mutations diagnosis is complicated. Here we report an overview of the main clinical findings and biochemical and molecular data of 13 CPS1D Italian patients. In two of them, one with the neonatal form and one with the late form, cadaveric auxiliary liver transplant was performed. Mutation analysis in these patients identified 17 genetic lesions, 9 of which were new confirming their "private" nature. Seven of the newly identified mutations were missense/nonsense changes. In order to study their protein level effects, we performed an in silico analysis whose results indicate that the amino acid substitutions occur at evolutionary conserved positions and affect residues necessary for enzyme stability or function.

Observational clinical study in juvenile-adult glycogenosis type 2 patients undergoing enzyme replacement therapy for up to 4 years

The objective of this study was to describe a large Italian cohort of patients with late-onset glycogen storage disease type 2 (GSDII) at various stages of disease progression and to evaluate the clinical effectiveness of alglucosidase alpha enzyme replacement therapy (ERT). Previous studies showed in late-onset patients ERT efficacy against placebo and variable response in uncontrolled studies. Seventy-four juvenile or adult GSDII patients were treated with ERT in a multicenter open label, non-randomized study, from 12 months up to 54 months. Recombinant human alpha glucosidase (rh-GAA) was injected by intravenous route at 20 mg/kg every second week. Patients were divided into three groups according to ERT duration: Group A received treatment for 12-23 months (n = 16), Group B for 24-35 months (n = 14), and Group C for more than 36 months (n = 44). Clinical assessment included a 6-min walk test (6MWT), forced vital capacity (FVC), the Walton and Gardner-Medwin score, the number of hours of ventilation, body mass index, echocardiography and blood creatine kinase (CK). Included in our cohort were 33 males and 41 females (M:F = 0.8:1), with a mean age at first symptoms of 28.3 years (range 2-55 years) and a mean age of 43 years at study entry (range 7-72 years). Seven wheelchair bound patients, as well as 27 patients requiring ventilation support, were included. After treatment we could observe an increase in distance walked on the 6MWT in the large majority of patients (48/58; 83%), with an overall mean increase of 63 m (from 320 ± 161 to 383 ± 178 m). After treatment in the majority of patients FVC was improved or unchanged (45/69; 65%). In ventilated patients we observed an improvement in average number of hours off the ventilator (from 15.6 to 12.1 h). Six patients stopped mechanical ventilation and two others started it. The effect of therapy was not related to ERT duration. Nine of 64 patients (13%) that underwent to echocardiography showed a variable degree of cardiac hypertrophy (left ventriculum or septum), and a positive effect was observed after 36 months of ERT in one adult case. Discontinuation of treatment occurred in four patients: one drop-off case, one patient died for a sepsis after 34 months of treatment and two patients stopped ERT for worsening of general clinical condition. Mild adverse effects were observed in four cases (5%). This study represents the largest cohort of late-onset GSDII patients treated with ERT, and confirm a positive effect of treatment. These results, obtained in a large case series on therapy, indicate a favourable effect of ERT therapy, even in more advanced stage of the disease.

Allelic and phenotypic heterogeneity in 49 Italian patients with the muscle form of CPT-II deficiency

As genotype-phenotype correlations require the study of large patient populations, we investigated 49 Italian patients (33 unreported) with the muscle form of carnitine-palmitoyl-transferase-II (CPT-II) deficiency and CPT2 gene mutations. CPT enzyme activity below 25% of controls would lead to the development of muscle symptoms, and CPT activity below 15% would cause a relatively severe phenotype of the muscle form. Of the 15 different mutations found, 6 are novel (40%). A functional significance of mutations could be derived only for the two homozygous missense mutations found: both the p.S113L and the p.R631C (recurring in four unrelated patients from a genetic isolate) alleles caused a severe CPT enzyme defect (15% and 7%, respectively) and a relatively severe clinical phenotype of the muscle form. We identified three genotypes (homozygous p.R631C, homozygous p.S113L, and heterozygous null mutations) usually associated with a relatively severe and often life-threatening condition, which should be considered both in the clinical management of newly diagnosed patients (to prevent symptoms) and in their possible inclusion in therapeutic trials. We confirmed the existence of symptomatic heterozygous patient(s), through a family study, providing an important issue when offering genetic counseling and suggesting the crucial role of polymorphisms or environmental factors in determining the phenotype.

Fabry disease: polymorphic haplotypes and a novel missense mutation in the GLA gene

Fabry disease: polymorphic haplotypes and a novel missense mutation in the GLA gene. Fabry disease (FD) is an X-linked lysosomal storage disorder with a heterogeneous spectrum of clinical manifestations that are caused by the deficiency of α-galactosidase A (α-Gal-A) activity. Although useful for diagnosis in males, enzyme activity is not a reliable biochemical marker in heterozygous females due to random X-chromosome inactivation, thus rendering DNA sequencing of the α-Gal-A gene, alpha-galactosidase gene (GLA), the most reliable test for the confirmation of diagnosis in females. The spectrum of GLA mutations is highly heterogeneous. Many polymorphic GLA variants have been described, but it is unclear if haplotypes formed by combinations of such variants correlate with FD, thus complicating molecular diagnosis in females with normal α-Gal-A activity. We tested 67 female probands with clinical manifestations that may be associated with FD and 110 control males with normal α-Gal-A activity. Five different combinations of GLA polymorphic variants were identified in 14 of the 67 females, whereas clearcut pathogenetic alterations, p.Met51Ile and p.Met290Leu, were identified in two cases. The latter has not been reported so far, and both mutant forms were found to be responsive to the pharmacological chaperone deoxygalactonojirimycin (DGJ; migalastat hydrochloride). Analysis of the male control population, as well as male relatives of a suspected FD female proband, permitted the identification of seven different GLA gene haplotypes in strong linkage disequilibrium. The identification of haplotypes in control males provides evidence against their involvement in the development of FD phenotypic manifestations.

Expanding CEP290 mutational spectrum in ciliopathies

Ciliopathies are an expanding group of rare conditions characterized by multiorgan involvement, that are caused by mutations in genes encoding for proteins of the primary cilium or its apparatus. Among these genes, CEP290 bears an intriguing allelic spectrum, being commonly mutated in Joubert syndrome and related disorders (JSRD), Meckel syndrome (MKS), Senior-Loken syndrome and isolated Leber congenital amaurosis (LCA). Although these conditions are recessively inherited, in a subset of patients only one CEP290 mutation could be detected. To assess whether genomic rearrangements involving the CEP290 gene could represent a possible mutational mechanism in these cases, exon dosage analysis on genomic DNA was performed in two groups of CEP290 heterozygous patients, including five JSRD/MKS cases and four LCA, respectively. In one JSRD patient, we identified a large heterozygous deletion encompassing CEP290 C-terminus that resulted in marked reduction of mRNA expression. No copy number alterations were identified in the remaining probands. The present work expands the CEP290 genotypic spectrum to include multiexon deletions. Although this mechanism does not appear to be frequent, screening for genomic rearrangements should be considered in patients in whom a single CEP290 mutated allele was identified.

Functional studies of new GLA gene mutations leading to conformational Fabry disease

Fabry Disease (FD) is an X-linked multisystemic lysosomal disorder caused by mutations of alpha-galactosidase (GLA) gene. Only a few of the 450 genetic lesions identified so far have been characterised by in vitro expression studies. Thus the significance of newly identified GLA nucleotide variants in FD patients which lead to alpha-galactosidase (GAL-A) amino acid substitutions or intronic changes can be uncertain. We identified three GLA mutations, c.155G>A (p.C52Y), c.548G>C (p.G183A), c.647A>G (p.Y216C) in as many individuals (two male; one female) and performed in vitro expression studies and Western blot analysis in order to clarify their functional effects. Reduced GAL-A activity and normal or partially reduced mutant proteins were present in all overexpressed mutant systems in which three-dimensional structural analysis showed that the active site was not directly involved. We hypothesize that the three new mutations affect the GAL-A protein, leading to conformational FD. When mutant proteins overexpressed in COS-1 cells and in patients' lymphocytes were tested in the presence of the 1-deoxygalactonojirimicin (DGJ) chaperone, the p.G183A and p.Y216C systems showed increased GAL-A enzyme activities and protein stabilisation while p.C52Y was not responsive. We underline that genetic, biochemical and functional studies are helpful in clarifying the consequences of the missense genetic lesions detected in FD. ERT is the elective therapy for Fabry patients, but it is not always possible to issue the enzyme's active form in all involved organs. Our study endorses the hypothesis that an active site-specific chemical chaperone, which could be administered orally, might be effective in treating GAL-A conformational defects.

Type II sialidosis: review of the clinical spectrum and identification of a new splicing defect with chitotriosidase assessment in two patients

Sialidosis is a lysosomal storage disease caused by the deficiency of alpha-N-acetyl neuraminidase-1 (NEU1). Sialidosis is classified into two main clinical variants: Type I, the milder form of the disease, and Type II, which can in turn be subdivided into three forms: congenital, infantile and juvenile. We report herein the clinical, biochemical and molecular characterisation of two patients with Type II sialidosis exhibiting the congenital (P1) and infantile forms (P2). We also review clinical data on the rare Type II forms of sialidosis in the hope of improving understanding of the disorder and facilitating its diagnosis. The genetic characterization of the two patients showed one known [c. 679G > A (p.G227R)] NEU1 missense mutation (detected in P2), and the new c.807 + 1G > A splicing defect (detected in P1), a genetic lesion that is extremely rare in this disease. Interestingly, P2 presented an extremely elevated level of chitotriosidase in plasma. This is the first pathological detection of chitotriosidase in sialidosis patients.

Reliability of the North Star Ambulatory Assessment in a multicentric setting

The aim of this study was to investigate the suitability of the North Star Ambulatory Assessment as a possible outcome measure in multicentric clinical trials. More specifically we wished to investigate the level of training needed for achieving a good interobserver reliability in a multicentric setting. The scale was specifically designed for ambulant children with Duchenne Muscular Dystrophy and includes 17 items that are relevant for this cohort. Thirteen Italian centers participated in the study. In the first phase of the study we provided two training videos and an example of the scale performed on a child. After the first session of training, all the 13 examiners were asked to send a video with an assessment performed in their centre and to score all the videos collected. There were no difficulties in performing the items and in obtaining adequate videos with a hand held camera but the results showed a poor interobserver reliability (<.5). After a second training session with review and discussion of the videos previously scored, the same examiners were asked to score three new videos. The results of this session had an excellent interobserver reliability (.995). The level of agreement was maintained even when the same videos were rescored after a month, showing a significant intra-observer reliability (.95). Our results suggest that the NSAA is a test that can be easily performed, completed in 10 min and can be used in a multicentric setting, providing that adequate training is administered.

Hypocitrullinemia in expanded newborn screening by LC-MS/MS is not a reliable marker for ornithine transcarbamylase deficiency

In an expanded newborn screening program for inborn errors of metabolism by LC-MS/MS in Tuscany, six newborns out of 169,000 showed decreased blood citrulline levels. In one of them, molecular analysis of the OTC gene identified the known p.Trp265Leu mutation, which is correlated with late-onset ornithine transcarbamylase deficiency (OTCD). Hypocitrullinemia is not a reliable marker for OTCD newborn screening, especially for late-onset forms that may exhibit normal citrulline levels. However, when hypocitrullinemia is detected in a newborn in whom intestinal dysfunction and prematurity have been excluded, OTCD should be investigated first because of the OTCD incidence (1:14,000) and the small size of the OTC gene coding sequence.

Diagnosis of glycogenosis type II

The diagnosis of glycogenosis type II is often complicated by the rarity of the condition and the heterogeneity of the clinical manifestations of the disease. It is a progressive, debilitating, and often fatal neuromuscular disorder that manifests as a continuum of clinical phenotypes, which vary with respect to organ involvement, age at onset, and severity. Early diagnosis requires both increased awareness among physicians regarding the clinical characteristics of the disease and fast and reliable acid alpha-glucosidase (GAA) enzyme activity assays to confirm the GAA deficiency. The clinical diagnosis of glycogenosis type II is confirmed by virtual absence (found in infants) and marked reduced activity (found in juveniles and adults) of GAA enzyme in blood samples, cultured fibroblasts, and muscle biopsies. This article specifically highlights the need for early recognition of the clinical manifestation of the disease in infants, juveniles, and adults. Descriptions of the main clinical features of the condition, as well as differential diagnosis are included. In addition, the tests required for a confirmed diagnosis are described, and use of muscle imaging to evaluate muscle pathology is reviewed.

Phenotypic variability, neurological outcome and genetics background of 6-pyruvoyl-tetrahydropterin synthase deficiency

This study aimed to investigate the clinical variability and factors implied in the outcome of 6-pyruvoyl-tetrahydropterin synthase deficiency (PTPSd). Biochemical and clinical phenotype, treatment variables, and 6-pyruvoyl-tetrahydropterin synthase (PTS) genotype, were explored retrospectively in 19 Italian patients (12 males and 7 females, aged 4 months to 33 years). According to the level of biogenic amines in cerebrospinal fluid (CSF) at the diagnosis, the patients were classified as mild (6) (normal level) or severe (13) (abnormal low level) form (MF and SF, respectively). Blood Phe ranged from 151 to 1053 micromol/l in MF (mean +/- SD: 698 +/- 403) and 342-2120 micromol/l in SF (mean +/- SD: 1175 +/- 517) (p = 0.063). Patients with MF showed a normal neurological development (a transient dystonia was detected in one), while all SF patients except one presented with severe neurological impairment and only four had a normal neurological development. The outcome of the SF was influenced by the precocity of the treatment. Serial CSF examinations revealed a decline of 5-hydroxyindolacetic acid in MFs and an incomplete restoration of neurotransmitters in SFs: neither obviously affected the prognosis. PTS gene analysis detected 17 different mutations (seven so far unreported) (only one affected allele was identified in three subjects). A good correlation was found between genotype and clinical and biochemical phenotype. The occurrence of brain neurotransmitter deficiency and its early correction (by the therapy) are the main prognostic factors in PTPSd.

Progress in expanded newborn screening for metabolic conditions by LC-MS/MS in Tuscany: update on methods to reduce false tests

We report on our 6-year experience of expanded newborn screening by tandem mass spectrometry in Tuscany (Italy), the first Italian Region to screen all newborns for more than 40 inborn errors of metabolism: organization, diseases observed and updates on methods to reduce false-positive and false-negative tests are described. Blood collection is recommended between 48 and 72 h of life. Blood spots are sent daily by courier to laboratory. When a positive result occurs, two subsequent procedures are followed: for disorders with possible acute metabolic decompensation, the baby is immediately recalled and clinical examinations and confirmatory tests are performed; for the other disorders, the nursery provides for a second blood spot. If the test is positive, clinical examinations and confirmatory tests are performed. In both cases, if confirmatory tests are positive, a treatment and a follow-up programme are started. Up to now, spots from 160 000 infants have been analysed and 80 affected patients have been identified (disorders of amino acids, organic acids and fatty acids metabolism). We describe adjustments to cut-off values, the introduction of a second-tier test for propionic acidaemia and for methylmalonic aciduria, the inclusion of succinylacetone in the panel of metabolites, and protocols for premature infants and for newborns on parenteral nutrition or transfused. These changes resulted in a reduction in recalls from 1.37% to 0.32% and consequently of working time and parental stress. Avoiding false-negatives by using more specific markers and minimizing the false-positive rate with second-tier testing is important for a successful newborn screening programme.

GALNS gene expression profiling in Morquio A patients' fibroblasts

BACKGROUND

Quantification studies of mutated mRNAs have not been carried out on Morquio A patients. Such studies are very important for the determination of stability of premature termination codons (PTC) bearing transcripts in order to assess the appropriateness of introducing the newly developed therapeutic strategies such as "stop codon read-through therapy".

METHODS

This paper focuses on the study of the GALNS gene and mRNAs in two severe forms of Morquio A patients' fibroblasts with development of a new and rapid real-time RT-PCR for detection and quantification of absolute mRNA copy number.

RESULTS

We identified two new mutations c.385A>T (p.K129X) and c.899-1G>C) in Pt1 and a known splicing defect c.120+1G>A in Pt2. Using RT-PCR and real-time RT-PCR in Pt2 we detected low levels of mRNAs, suggesting its instability; in Pt1, we detected three aberrant mRNAs introducing premature stop codons, suggesting that both the c.385A>T and c.899-1G>C mutations produce mRNAs capable of escaping the nonsense-mediated decay (NMD) pathway.

CONCLUSIONS

The development of a real-time RT-PCR assay allows to absolutely quantify the GALNS mRNAs carrying mutations that lead to PTCs bearing transcripts, which escape the NMD process and are potentially suitable for the new therapeutic approach.

Caveolin-3 T78M and T78K missense mutations lead to different phenotypes in vivo and in vitro

Caveolins are the principal protein components of caveolae, invaginations of the plasma membrane involved in cell signaling and trafficking. Caveolin-3 (Cav-3) is the muscle-specific isoform of the caveolin family and mutations in the CAV3 gene lead to a large group of neuromuscular disorders. In unrelated patients, we identified two distinct CAV3 mutations involving the same codon 78. Patient 1, affected by dilated cardiomyopathy and limb girdle muscular dystrophy (LGMD)-1C, shows an autosomal recessive mutation converting threonine to methionine (T78M). Patient 2, affected by isolated familiar hyperCKemia, shows an autosomal dominant mutation converting threonine to lysine (T78K). Cav-3 wild type (WT) and Cav-3 mutations were transiently transfected into Cos-7 cells. Cav-3 WT and Cav-3 T78M mutant localized at the plasma membrane, whereas Cav-3 T78K was retained in a perinuclear compartment. Cav-3 T78K expression was decreased by 87% when compared with Cav-3 WT, whereas Cav-3 T78M protein levels were unchanged. To evaluate whether Cav-3 T78K and Cav-3 T78M mutants behaved with a dominant negative pattern, Cos-7 cells were cotransfected with green fluorescent protein (GFP)-Cav-3 WT in combination with either mutant or WT Cav-3. When cotransfected with Cav-3 WT or Cav-3 T78M, GFP-Cav-3 WT was localized at the plasma membrane, as expected. However, when cotransfected with Cav-3 T78K, GFP-Cav-3 WT was retained in a perinuclear compartment, and its protein levels were reduced by 60%, suggesting a dominant negative action. Accordingly, Cav-3 protein levels in muscles from a biopsy of patient 2 (T78K mutation) were reduced by 80%. In conclusion, CAV3 T78M and T78K mutations lead to distinct disorders showing different clinical features and inheritance, and displaying distinct phenotypes in vitro.

Mutations in the cyclic adenosine monophosphate response element of the tyrosine hydroxylase gene

Tyrosine hydroxylase (TH) deficiency (OMIM 191290) is one cause of early-onset dopa-responsive dystonia. We describe seven cases from five unrelated families with dopa-responsive dystonia and low homovanillic acid in cerebrospinal fluid who were suspected to suffer from TH deficiency. Analysis of part of the TH promotor showed five homozygous and two heterozygous mutations in the highly conserved cyclic adenosine monophosphate response element. Our data suggest that, if no mutations are found in the coding regions of the gene in patients strongly suspected of TH deficiency, the search for pathogenic mutations should be extended to regulatory promotor elements.

Fatal malonyl CoA decarboxylase deficiency due to maternal uniparental isodisomy of the telomeric end of chromosome 16

Malonic aciduria is a rare autosomal recessive disorder caused by deficiency of malonyl-CoA decarboxylase, encoded by the MLYCD gene. We report on a patient with clinical presentation in the neonatal period. Metabolic investigations led to a diagnosis of malonyl-CoA decarboxylase deficiency, confirmed by decreased activity in cultured fibroblasts. High doses of carnitine and a diet low in lipids led to a reduction in malonic acid excretion, and to an improvement in his clinical conditions, but at the age of 4 months he died suddenly and unexpectedly. No autopsy was performed. Molecular analysis of the MLYCD gene performed on the proband's RNA and genomic DNA identified a previously undescribed mutation (c.772-775delACTG) which was homozygous. This mutation was present in his mother but not in his father; paternity was confirmed by microsatellite analysis. A hypothesis of maternal uniparental disomy (UPD) was investigated using fourteen microsatellite markers on chromosome 16, and the results confirmed maternal UPD. Maternal isodisomy of the 16q24 region led to homozygosity for the MLYCD mutant allele, causing the patient's disease. These findings are relevant for genetic counselling of couples with a previously affected child, since the recurrence risk in future pregnancies is dramatically reduced by the finding of UPD. In addition, since the patient had none of the clinical manifestations previously associated with maternal UPD 16, this case provides no support for the existence of maternally imprinted genes on chromosome 16 with a major effect on phenotype.

Hyperkalemia after acute metabolic decompensation in two children with vitamin B12-unresponsive methylmalonic acidemia and normal renal function

The patients affected by vitamin B12-unresponsive methylmalonic acidemia (MMA) on the long run develop chronic renal disease with interstitial nephropathy and progressive renal insufficiency. The mechanism of nephrotoxicity in vitamin B12-unresponsive MMA is not yet known. Chronic hyporeninemic hypoaldosteronism has been found in many cases of methylmalonic acidemia, hyperkalemia and renal tubular acidosis type 4. We report 2 patients affected by B12-unresponsive methylmalonic acidemia diagnosed at the age of 23 months and 5 years, respectively, with normal glomerular filtration and function. They showed hyporeninemic hypoaldosteronism and significant hyperkalemia requiring sodium potassium exchange resin (Kayexalate) therapy after an episode of metabolic decompensation leading to diagnosis of MMA. In both children, hyporeninemic hypoaldosteronism and hyperkalemia disappeared after 6 months of good metabolic control.

Genetic and biochemical approach to early prenatal diagnosis in a family with mut methylmalonic aciduria

Genetic and biochemical prenatal diagnosis was performed at 11 weeks of gestation in a family with a proband affected by mut methylmalonic aciduria (MMA) and homozygotes for the MUT gene c.643G>A (p.Gly215Ser) mutation. Both chorionic villus and amniotic fluid samples were used. The presence of high levels of methylmalonic acid and propionylcarnitine determined by gas chromatography/mass spectrometry and LC/MS/MS analysis, respectively, and the identification of the p.Gly215Ser at a homozygous level in foetal DNA allowed a certain, rapid and early diagnosis. To our knowledge, this is the first mut MMA prenatal diagnosis carried out by genetic and biochemical approach.

Pre- and post-dialysis quantitative dosage of thymidine in urine and plasma of a MNGIE patient by using HPLC-ESI-MS/MS

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive disorder characterized by severe gastrointestinal dysmotility, cachexia, ptosis, ophthalmoparesis, peripheral neuropathy and leukoencephalopathy. The disease is due to a thymidine phosphorylase defect. This enzyme catalyses the phosphorolysis of thymidine to thymine and deoxyribose 1-phosphate. For this reason, increased levels of thymidine in plasma and urine are found in MNGIE patients. Haemodialysis can reduce circulating plasma thymidine levels and can be beneficial in some MNGIE patients. We developed a fast analytical method based on HPLC-ESI-MS/MS capable of identifying pyrimidine nucleotides (thymine, cytosine, uracil) and nucleosides (thymidine, citidine, uridine) in plasma and urine after direct dilution of the samples without pre-treatment. In the patient studied, we observed a significant reduction of plasmatic and urinary thymidine levels during and after dialysis. However, we noted a progressive reduction of the initial thymidine level after some dialytic trials. This method will be useful not only for thymidine level follow-up during dialysis in MNGIE patients but also for the improvement of the diagnosis or diagnostic suspect in other pyrimidine defects such as dihydropyrimidine dehydrogenase deficiency, dihydropyrimidinase deficiency and ureidopropionase deficiency.

Phenotypic heterogeneity in two unrelated Danon patients associated with the same LAMP-2 gene mutation

Danon disease, an X-linked cardioskeletal myopathy caused by primary deficiency of lysosome-associated membrane protein-2 (LAMP-2), is clinically characterized by cardiomyopathy, myopathy, and variable mental retardation. The pathological hallmark of the disease is the absence of LAMP-2 immunohistochemical staining in muscle. The LAMP-2 gene mutations reported thus far are generally private mutations. We describe two cases of Danon disease with different clinical presentation, in whom we identified the same exon skipping mutation c.928G>A in the LAMP-2 gene. The first patient was affected by an early onset myopathy and hypertrophic cardiomyopathy (HCM) that partially improved with drug treatment. A first muscle biopsy at age 4 months showed markedly increased glycogen, and acid maltase deficiency was ruled out biochemically. A second muscle biopsy, performed at age 3(1/2) years, showed very mild abnormalities. The second child at age 15 years had mild, diffuse muscle weakness and wasting, moderate mental deficiency, and HCM. Two serial biopsies performed at age 8 and 15 years showed similar findings of multiple esterase-positive vacuoles in type I myofibers. In both patients the immunohistochemical study demonstrated the absence of LAMP-2 in skeletal muscle.

Clinical and genetic heterogeneity of branching enzyme deficiency (glycogenosis type IV)

BACKGROUND

Glycogen storage disease type IV (GSD-IV) is a clinically heterogeneous autosomal recessive disorder due to glycogen branching enzyme (GBE) deficiency and resulting in the accumulation of an amylopectin-like polysaccharide. The typical presentation is liver disease of childhood, progressing to lethal cirrhosis. The neuromuscular form of GSD-IV varies in onset (perinatal, congenital, juvenile, or adult) and severity.

OBJECTIVE

To identify the molecular bases of different neuromuscular forms of GSD-IV and to establish possible genotype/phenotype correlations.

METHODS

Eight patients with GBE deficiency had different neuromuscular presentations: three had fetal akinesia deformation sequence (FADS), three had congenital myopathy, one had juvenile myopathy, and one had combined myopathic and hepatic features. In all patients, the promoter and the entire coding region of the GBE gene at the RNA and genomic level were sequenced.

RESULTS

Nine novel mutations were identified, including nonsense, missense, deletion, insertion, and splice-junction mutations. The three cases with FADS were homozygous, whereas all other cases were compound heterozygotes.

CONCLUSIONS

This study expands the spectrum of mutations in the GBE gene and confirms that the neuromuscular presentation of GSD-IV is clinically and genetically heterogeneous.

Clinical and molecular findings in children with complex I deficiency

Isolated complex I deficiency, the most frequent OXPHOS disorder in infants and children, is genetically heterogeneous. Mutations have been found in seven mitochondrial DNA (mtDNA) and eight nuclear DNA encoded subunits, respectively, but in most of the cases the genetic basis of the biochemical defect is unknown. We analyzed the entire mtDNA and 11 nuclear encoded complex I subunits in 23 isolated complex I-deficient children, classified into five clinical groups: Leigh syndrome, progressive leukoencephalopathy, neonatal cardiomyopathy, severe infantile lactic acidosis, and a miscellaneous group of unspecified encephalomyopathies. A genetic definition was reached in eight patients (35%). Mutations in mtDNA were found in six out of eight children with Leigh syndrome, indicating a prevalent association between this phenotype and abnormalities in ND genes. In two patients with leukoencephalopathy, homozygous mutations were detected in two different nuclear-encoded complex I genes, including a novel transition in NDUFS1 subunit. In addition to these, a child affected by mitochondrial encephalomyopathy had heterozygous mutations in NDUFA8 and NDUFS2 genes, while another child with neonatal cardiomyopathy had a complex rearrangement in a single NDUFS7 allele. The latter cases suggest the possibility of unconventional patterns of inheritance in complex I defects.

Mutational spectrum in ten Italian patients affected by methylmalonyl-CoA mutase deficiency

We report seven novel mutations, including three amino acids substitutions (p.Glu286Lys, p.Cys560Tyr, p.Pro615Leu), two nonsense mutations (p.Arg31X, p.Glu 451X), one splicing defect (c.2125-1G >A), one small deletion (c.1758-1759delA) and nine previously described mutations identified in 10 unrelated Italian patients affected by mut MMA.

Successful prenatal molecular diagnosis of carbamyl-phosphate synthetase I deficiency in two at-risk pregnancies

We report the two first prenatal diagnoses in an Italian family with a proband affected by neonatal carbamyl-phosphate synthetase I deficiency in which molecular analysis identified V457G and Q810R amino acid substitutions. We performed a prenatal diagnosis on genomic DNA isolated from chorionic villus and amniotic fluid samples collected at 13 weeks of gestation. In the first pregnancy, the fetus was compound heterozygous for the mutations and termination of pregnancy was elected. The genetic lesions were also confirmed on genomic DNA isolated from the fetus's liver and skin fibroblasts. A few months later, we performed a second prenatal diagnosis in this family. The second fetus was heterozygous for the wild-type alleles. The pregnancy was continued and a girl was born at 41 weeks of gestation. We have confirmed the wild-type state on the baby's DNA.

Mutational analysis of the AGL gene: five novel mutations in GSD III patients

Total or partial lack of glycogen debranching enzyme (GDE or AGL, amylo-1,6-glucosidase, 4-alpha-glucanotransferase) is responsible for Glycogen Storage Disease type III (GSDIII), a rare autosomal recessive disorder of glycogen metabolism. The clinical and biochemical features of GSDIII subjects are quite heterogeneous, and this mirrors the genotype-phenotype heterogeneity among patients. In this paper, we report the molecular characterisation of five unrelated subjects, four Italian and one Tunisian. The following new mutations are described and confirm the genetic heterogeneity of this disease: p.R864X, p.R428K, c.3911 insA, p.G1087R and c.3512_3549dup+c.3512_3519del. The functional relevance of these mutations is discussed on the basis of the recently acquired knowledge about the boundaries and structures of the two catalytic domains.

Structural organization of the human carbamyl phosphate synthetase I gene (CPS1) and identification of two novel genetic lesions

Carbamyl Phosphate Synthetase I deficiency (CPSID) is a rare autosomal recessive urea cycle disorder usually characterized by potentially lethal neonatal hyperammonemia. The large (5215 bp) CPS1-cDNA, expressed only in liver and epithelial cells of intestinal mucosa, has been cloned. Until now the CPS1 genomic organization was unknown. Taking advantage of the phylogenetic lineage between the CPS1 gene of Homo sapiens and Rattus norvegicus, we determined the intron-exon organization of the human CPS1 gene. Starting from the ATG codon, the CPS I gene is organized in 38 exons spanning from 50bp to 200 bp. We also report the molecular studies on an Italian patient affected by neonatal CPSD. Two novel genetic lesions (c.1370T>G and c.2429A>G) that lead to the novel amino acid substitutions V457G and Q810R, and the known N1406T polymorphism, were detected in the patient's CPS1 RNA and in genomic DNA isolated from peripheral blood lymphocytes. The characterization of the CPS1 genomic organization will allow the identification of the genetic lesions of CPSD patients, the detection of carriers, better genetic counseling and a more certain, less invasive method of prenatal diagnosis.

Molecular characterisation of GSD III subjects and identification of six novel mutations in AGL

Deficiency of amylo-1,6-glucosidase, 4-alpha-glucanotransferase enzyme (AGL or glycogen debranching enzyme) is causative of Glycogen Storage Disease type III, a rare autosomal recessive disorder of glycogen metabolism. The disease has been demonstrated to show clinical and biochemical heterogeneity, reflecting the genotype-phenotype heterogeneity among different subjects. The aim of this study was the molecular characterisation of eight unrelated patients from an ethnically heterogeneous population (six Italians, one from India and another one from Tunisia). We describe six novel mutations responsible for the disease (C234R, R675W, 2547delG, T38A, W1327X, IVS6 +3 A>G) and the presence in two Italian subjects of a splice variant (IVS21(+1) G>A) already described elsewhere. This last one is confirmed to be the most frequent mutation among the Italian patients come to our observation, accounting for 28% of 21 patients. One subject was found to be a compound heterozygous. Our data confirm the substantial genetic heterogeneity of this disease. Consequently, the strategy of mutation finding based on screening of recurrent common mutations is limited, as far as regards Italian GSD III patients, to check for the presence of IVS21(+1) G>A.

Two novel genetic lesions and a common BH4-responsive mutation of the PAH gene in Italian patients with hyperphenylalaninemia

Hyperphenylalaninemia (HPA), due to a deficiency of phenylalanine hydroxylase (PAH) enzyme, is caused by mutations in the PAH gene. Molecular analysis in 23 Italian patients with PAH deficiency identified two novel (P281R, L287V) and 20 previously described genetic lesions in the PAH gene. The detection of the A403V amino acid substitution in combination with null mutations in patients with BH4-responsive PAH deficiency leads us to correlate it with BH4 responsiveness.

Molecular analysis of 30 mucopolysaccharidosis type I patients: evaluation of the mutational spectrum in Italian population and identification of 13 novel mutations

Mucopolysaccharidosis type I (MPS-I orMPS1) is an autosomal recessive condition characterized by a broad range of clinical symptoms. Molecular diagnosis of MPS-I is important for analyzing genotype-phenotype correlation and for selecting patients for innovative therapies. In this study we analyzed 30 Italian MPS-I patients with different phenotypes (20 severe, 6 intermediate, 4 mild) in an attempt to recognize the mutational spectrum in our population and to identify major DNA alterations specific to our country. We identified 93% of mutated alleles (56 out of 60) with the reconstruction of the complete genotype in 26 patients out of 30. Twenty-three different mutations were found, 13 of which are novel while the remaining 10 have been already described. Among the novel mutations we found 5 non conservative missense mutations (A160D, E178K, P183R, G197D, D349Y), one nonsense mutation (C53X), 6 deletions (468-470del3, 486-491del6, 755-759del5, 1251delC, 1839-1867del29, 1902-1903del2), and one splice site mutation (IVS11+5G>A). No common mutation for MPS-I is present in our country. Frequently (40% of the alleles), mutations were found in just one or two patients. However, Q70X, P533R, G51D, and W402X mutations were present in several patients (15%, 13.3%, 13.3%, and 11.6% of the alleles respectively) suggesting a Mediterranean origin of the P533R and G51D mutations. In most cases the patients' genotypes were unique combinations of mutations. The great heterogeneity found in our MPS-I population hampers mutation detection and hinders the genotype-phenotype correlation.