Disease characteristics, effectiveness, and safety of vestronidase alfa for the treatment of patients with mucopolysaccharidosis VII in a novel, longitudinal, multicenter disease monitoring program.

BACKGROUND: Mucopolysaccharidosis VII (MPS VII) is an ultra-rare, autosomal recessive, debilitating, progressive lysosomal storage disease caused by reduced activity of ß-glucuronidase (GUS) enzyme. Vestronidase alfa (recombinant human GUS) intravenous enzyme replacement therapy is an approved treatment for patients with MPS VII. METHODS: This disease monitoring program (DMP) is an ongoing, multicenter observational study collecting standardized real-world data from patients with MPS VII (N ≈ 50 planned) treated with vestronidase alfa or any other management approach. Data are monitored and recorded in compliance with Good Clinical Practice guidelines and planned interim analyses of captured data are performed annually. Here we summarize the safety and efficacy outcomes as of 17 November 2022. RESULTS: As of the data cutoff date, 35 patients were enrolled: 28 in the Treated Group and seven in the Untreated Group. Mean (SD) age at MPS VII diagnosis was 4.5 (4.0) years (range, 0.0 to 12.4 years), and mean (SD) age at DMP enrollment was 13.9 (11.1) years (range, 1.5 to 50.2 years). Ten patients (29%) had a history of nonimmune hydrops fetalis. In the 23 patients who initiated treatment prior to DMP enrollment, substantial changes in mean excretion from initial baseline to DMP enrollment were observed for the three urinary glycosaminoglycans (uGAGs): dermatan sulfate (DS), -84%; chondroitin sulfate (CS), -55%; heparan sulfate (HS), -42%. Also in this group, mean reduction from initial baseline to months 6, 12, and 24 were maintained for uGAG DS (-84%, -87%, -89%, respectively), CS (-70%, -71%, -76%, respectively), and HS (+ 3%, -32%, and - 41%, respectively). All adverse events (AEs) were consistent with the known vestronidase alfa safety profile. No patients discontinued vestronidase alfa. One patient died. CONCLUSIONS: To date, the DMP has collected invaluable MPS VII disease characteristic data. The benefit-risk profile of vestronidase alfa remains unchanged and favorable for its use in the treatment of pediatric and adult patients with MPS VII. Reductions in DS and CS uGAG demonstrate effectiveness of vestronidase alfa to Month 24. Enrollment is ongoing.

Exploring genetic testing requests, genetic alterations and clinical associations in a cohort of children with autism spectrum disorder.

Several studies show great heterogeneity in the type of genetic test requested and in the clinicopathological characteristics of patients with ASD. The following study aims, firstly, to explore the factors that might influence professionals' decisions about the appropriateness of requesting genetic testing for their patients with ASD and, secondly, to determine the prevalence of genetic alterations in a representative sample of children with a diagnosis of ASD. Methods: We studied the clinical factors associated with the request for genetic testing in a sample of 440 children with ASD and the clinical factors of present genetic alterations. Even though the main guidelines recommend genetic testing all children with an ASD diagnosis, only 56% of children with an ASD diagnosis were genetically tested. The prevalence of genetic alterations was 17.5%. These alterations were more often associated with intellectual disability and dysmorphic features. There are no objective data to explicitly justify the request for genetic testing, nor are there objective data to justify requesting one genetic study versus multiple studies. Remarkably, only 28% of males were genetically tested with the recommended tests (fragile X and CMA). Children with dysmorphic features and organic comorbidities were more likely to be genetic tested than those without. Previous diagnosis of ASD (family history of ASD) and attendance at specialist services were also associated with Genetically tested Autism Spectrum Disorder GTASD. Our findings emphasize the importance of establishing algorithms to facilitate targeted genetic consultation for individuals with ASD who are likely to benefit, considering clinical phenotypes, efficiency, ethics, and benefits.

Developmental outcome of electroencephalographic findings in SYNGAP1 encephalopathy.

SYNGAP1 haploinsufficiency results in a developmental and epileptic encephalopathy (DEE) causing generalized epilepsies accompanied by a spectrum of neurodevelopmental symptoms. Concerning interictal epileptiform discharges (IEDs) in electroencephalograms (EEG), potential biomarkers have been postulated, including changes in background activity, fixation-off sensitivity (FOS) or eye closure sensitivity (ECS). In this study we clinically evaluate a new cohort of 36 SYNGAP1-DEE individuals. Standardized questionnaires were employed to collect clinical, electroencephalographic and genetic data. We investigated electroencephalographic findings, focusing on the cortical distribution of interictal abnormalities and their changes with age. Among the 36 SYNGAP1-DEE cases 18 presented variants in the SYNGAP1 gene that had never been previously reported. The mean age of diagnosis was 8 years and 8 months, ranging from 2 to 17 years, with 55.9% being male. All subjects had global neurodevelopmental/language delay and behavioral abnormalities; 83.3% had moderate to profound intellectual disability (ID), 91.7% displayed autistic traits, 73% experienced sleep disorders and 86.1% suffered from epileptic seizures, mainly eyelid myoclonia with absences (55.3%). A total of 63 VEEGs were revised, observing a worsening of certain EEG findings with increasing age. A disorganized background was observed in all age ranges, yet this was more common among older cases. The main IEDs were bilateral synchronous and asynchronous posterior discharges, accounting for ≥50% in all age ranges. Generalized alterations with maximum amplitude in the anterior region showed as the second most frequent IED (≥15% in all age ranges) and were also more common with increasing age. Finally, diffuse fast activity was much more prevalent in cases with 6 years or older. To the best of our knowledge, this is the first study to analyze EEG features across different age groups, revealing an increase in interictal abnormalities over infancy and adolescence. Our findings suggest that SYNGAP1 haploinsufficiency has complex effects in human brain development, some of which might unravel at different developmental stages. Furthermore, they highlight the potential of baseline EEG to identify candidate biomarkers and the importance of natural history studies to develop specialized therapies and clinical trials.

Description of the molecular and clinical characteristics of the mucopolysaccharidosis type VII Iberian cohort.

BACKGROUND: Mucopolysaccharidosis type VII (Sly syndrome) is an ultra-rare neurometabolic disorder caused by inherited deficiency of the lysosomal enzyme ß-glucuronidase. Precise data regarding its epidemiology are scarce, but birth prevalence is estimated to vary from 0.02 to 0.24 per 100,000 live births. The clinical course and disease progression are widely heterogeneous, but most patients have been reported to show signs such as skeletal deformities or cognitive delay. Additionally, detection criteria are not standardized, resulting in delayed diagnosis and treatment. METHODS: We present a cohort of 9 patients with mucopolysaccharidosis VII diagnosed in the Iberian Peninsula, either in Spain or Portugal. The diagnostic approach, genetic studies, clinical features, evolution and treatment interventions were reviewed. RESULTS: We found that skeletal deformities, hip dysplasia, hydrops fetalis, hepatosplenomegaly, hernias, coarse features, respiratory issues, and cognitive and growth delay were the most common features identified in the cohort. In general, patients with early diagnostic confirmation who received the appropriate treatment in a timely manner presented a more favorable clinical evolution. CONCLUSIONS: This case series report helps to improve understanding of this ultra-rare disease and allows to establish criteria for clinical suspicion or diagnosis, recommendations, and future directions for better management of patients with Sly syndrome.

Genotype-phenotype correlation of 17 cases of Pompe disease in Spanish patients and identification of 4 novel GAA variants.

BACKGROUND: Pompe disease (PD) is an autosomal recessive metabolic disorder caused by pathogenic variants in the acid α-glucosidase gene (GAA) that produces defects in the lysosomal acid α-1,4-glucosidase. We aimed to identify genetic variations and clinical features in Spanish subjects to establish genotype-phenotype correlation. METHODS: A total of 2637 samples of patients who showed symptoms or susceptible signs of PD were enrolled in this observational study. Enzymatic activity was detected by fluorometric techniques and the genetic study was carried out using Next-Generation Sequencing. RESULTS: Fourteen different variants from 17 diagnosed patients were identified, seven males and nine females with LOPD (mean age 36.07, SD 20.57, range 7-64) and a 2-day-old boy with IOPD, four genetic variants had not been described in the literature previously, including a homozygous variant. In all of them α-glucosidase activity was decreased. Muscle weakness, respiratory distress, exercise intolerance, hypotonia, dysphagia and myalgia were commonly observed in patients. CONCLUSIONS: This study report four new genetic variants that contribute to the pathogenic variants spectrum of the GAA gene. We confirm that patients in Spain have a characteristic profile of a European population, with c.-32-13T>G being the most prevalent variant. Furthermore, it was confirmed that the c.236_246delCCACACAGTGC pathogenic variant in homozygosity is associated with early disease and a worse prognosis.

Accuracy diagnosis improvement of Fabry disease from dried blood spots: Enzyme activity, lyso-Gb3 accumulation and GLA gene sequencing.

The purpose of this study was to examine the applicability of the use of samples in dried blood spot (DBS) for the definitive diagnosis of Fabry disease (FD) in males and females and to compare the diagnostic role of α-galactosidase A activity (α-Gal A), levels of lyso-Gb3 and sequencing of the GLA gene in screening patients with suspected FD. Measurement of α-Gal A activity in suspected FD patients in DBS was made followed by lyso-Gb3 determination and GLA gene sequencing. Of the 2381 subjects analyzed, FD was confirmed in 24 patients. Thirteen different variants were considered like pathogenic, five of which had not been previously described (c.143A > G; c.455A > C; c.487G > T; c.554delA; c.1045_1046insA). None of the patients with normal enzyme activity had FD confirmation. The DBS measurement of α-Gal A was more sensitive than lyso-Gb3 levels in both men and women. Definitive diagnosis of FD from a single DBS is possible, allowing samples to be easily sent from anywhere to the reference laboratory.

Lacosamide intake during pregnancy increases the incidence of foetal malformations and symptoms associated with schizophrenia in the offspring of mice.

The use of first and second generation antiepileptic drugs during pregnancy doubles the risk of major congenital malformations and other teratogenic defects. Lacosamide (LCM) is a third-generation antiepileptic drug that interacts with collapsing response mediator protein 2, a protein that has been associated with neurodevelopmental diseases like schizophrenia. The aim of this study was to test the potential teratogenic effects of LCM on developing embryos and its effects on behavioural/histological alterations in adult mice. We administered LCM to pregnant mice, assessing its presence, and that of related compounds, in the mothers' serum and in embryonic tissues using liquid chromatography coupled to quadrupole/time of flight mass spectrometry detection. Embryo morphology was evaluated, and immunohistochemistry was performed on adult offspring. Behavioural studies were carried out during the first two postnatal weeks and on adult mice. We found a high incidence of embryonic lethality and malformations in mice exposed to LCM during embryonic development. Neonatal mice born to dams treated with LCM during gestation displayed clear psychomotor delay and behavioural and morphological alterations in the prefrontal cortex, hippocampus and amygdala that were associated with behaviours associated with schizophrenia spectrum disorders in adulthood. We conclude that LCM and its metabolites may have teratogenic effects on the developing embryos, reflected in embryonic lethality and malformations, as well as behavioural and histological alterations in adult mice that resemble those presented by patients with schizophrenia.

Genetic Diagnosis of Rare Diseases: Past and Present.

Rare diseases are heterogeneous life-threatening or seriously debilitating conditions that affect < 1 in 2000 individuals, and most have a genetic component. The diagnostic process is usually based on classic clinical practices, such as physical examination, personal and family history (inheritance pattern), laboratory tests and image studies, but diagnosis can be delayed several years after the initiation of symptoms. The advances in molecular genetics that have taken place in recent years have led to an important shift in medical practice and in its approach to the diagnosis and treatment of many rare diseases. The objective of this review is to promote a better understanding of the mechanisms underlying genetic diseases in humans and the tools available for their diagnosis. A practical example of X-linked hypophosphataemic rickets is described.

Further definition of the proximal 19p13.3 microdeletion/microduplication syndrome and implication of PIAS4 as the major contributor.

The proximal 19p13.3 microdeletion/microduplication (prox19p13.3del/dup) syndrome is a recently described disorder with common clinical features including developmental delay, intellectual disability, speech delay, facial dysmorphic features with ear defects, anomalies of the hands and feet, umbilical hernia and hypotonia. While deletions are associated with macrocephaly, patients with duplications have microcephaly. The smallest region of overlap in multiple patients (113.5 kb) included three genes and one pseudogene, with a suggested major role of PIAS4 in determination of the phenotype and head size in these patients. Here, we refine the prox19p13.3del/dup with four additional patients: two with microdeletions, one with microduplication and one family with single-nucleotide nonsense variant in PIAS4. The patient with the PIAS4 loss of function variant displayed a phenotype quite similar to deletion patients -including the macrocephaly and many other core features of the syndrome. Patient's SNV was inherited from her mother who is similarly affected. Thus, our data indicate that PIAS4 is a major contributor to the proximal 19p13.3del/dup syndrome phenotype. In summary, we report the first patient with a pathogenic variant in PIAS4- and three additional rearrangements at the proximal 19p13.3 locus. These observations add further evidence about the molecular basis of this microdeletion/microduplication syndrome.

Expanding the clinical and mutational spectrum of germline ABL1 mutations-associated syndrome: A case report.

RATIONALE: Clinical and genetic management of patients with rare syndromes is often a difficult, confusing, and slow task. PATIENT CONCERNS: Male child patient with a multisystemic disease showing congenital heart defects, facial dysmorphism, skeletal malformations, and eye anomalies. DIAGNOSIS: The patient remained clinically undiagnosed until the genetic results were conclusive and allowed to associate its clinical features with the germline ABL1 mutations-associated syndrome. INTERVENTIONS: We performed whole-exome sequencing to uncover the underlying genetic defect in this patient. Subsequently, family segregation of identified mutations was performed by Sanger sequencing in all available family members. OUTCOMES: The only detected variant compatible with the disease was a novel heterozygous nonframeshift de novo deletion in ABL1 (c.434_436del; p.Ser145del). The affected residue lays in a functional domain of the protein, it is highly conserved among distinct species, and its loss is predicted as pathogenic by in silico studies. LESSONS: Our results reinforce the involvement of ABL1 in clinically undiagnosed cases with developmental defects and expand the clinical and genetic spectrum of the recently reported ABL1-associated syndrome. In this sense, we described the third germline ABL1 causative mutation and linked, for the first time, ocular anterior chamber anomalies to this pathology. Thus, we suggest that this disorder may be more heterogeneous than is currently believed and may be overlapping with other multisystemic diseases, hence genetic and clinical reassessment of this type of cases should be considered to ensure proper diagnosis.

Diagnosis and follow-up of patients with Hunter syndrome in Spain: A Delphi consensus.

Hunter syndrome or mucopolysaccharidosis type II (MPSII) is a progressive multisystem X-linked lysosomal storage disease caused by mutations in the IDS gene that shows a wide spectrum of clinical symptoms and severity. Idursulfase, a specific enzyme replacement therapy (ERT) for MPSII, has been available since 2007. ERT, along with symptomatic management of patients, is fundamental for improving patient prognosis and quality of life. The aims of this study were to investigate whether Spanish pediatricians who are experts in managing the disease agreed with current international guidelines regarding MPSII patient diagnosis and follow-up; and to reach a consensus regarding which items are essential for the diagnosis, follow-up, and treatment of these patients in Spain.An advisory panel of 5 experts from the Hunter Spanish Working Group reviewed key studies, developed a questionnaire based on a modified Delphi method, sent the questionnaire to selected experts, and reviewed the responses. The final questionnaire had 83 items in the following categories: diagnosis, ERT considerations after diagnosis, Periodic assessments, and ERT considerations during follow-up. A total of 85 experts were invited to participate; 28 (35%) responded and showed a strong consensus for most items. The advisory panel decided not to perform a second Delphi round. There was strong agreement (>3.1 median value; range, 1 to 4) for 43/56 items in Diagnosis, for 4/6 items in "ERT considerations after diagnosis," for 6/16 items in "Periodic assessments," and for 3/5 items in "ERT considerations during follow-up." Most responses were in agreement with international guidelines, and controversial items were discussed by the advisory panel. Based on the results, on the key studies, and on clinical experience and opinions, the panel developed and scheduled recommendations for the diagnosis and follow-up of patients with MPSII.An expert 5-person panel oversaw a Delphi survey of 28 pediatricians and reached a consensus on recommendations for the diagnosis and follow-up of MPSII patients. This document will help guide clinicians involved in the diagnosis, management, and treatment of MPSII.

ACTB Loss-of-Function Mutations Result in a Pleiotropic Developmental Disorder.

ACTB encodes ß-actin, an abundant cytoskeletal housekeeping protein. In humans, postulated gain-of-function missense mutations cause Baraitser-Winter syndrome (BRWS), characterized by intellectual disability, cortical malformations, coloboma, sensorineural deafness, and typical facial features. To date, the consequences of loss-of-function ACTB mutations have not been proven conclusively. We describe heterozygous ACTB deletions and nonsense and frameshift mutations in 33 individuals with developmental delay, apparent intellectual disability, increased frequency of internal organ malformations (including those of the heart and the renal tract), growth retardation, and a recognizable facial gestalt (interrupted wavy eyebrows, dense eyelashes, wide nose, wide mouth, and a prominent chin) that is distinct from characteristics of individuals with BRWS. Strikingly, this spectrum overlaps with that of several chromatin-remodeling developmental disorders. In wild-type mouse embryos, ß-actin expression was prominent in the kidney, heart, and brain. ACTB mRNA expression levels in lymphoblastic lines and fibroblasts derived from affected individuals were decreased in comparison to those in control cells. Fibroblasts derived from an affected individual and ACTB siRNA knockdown in wild-type fibroblasts showed altered cell shape and migration, consistent with known roles of cytoplasmic ß-actin. We also demonstrate that ACTB haploinsufficiency leads to reduced cell proliferation, altered expression of cell-cycle genes, and decreased amounts of nuclear, but not cytoplasmic, ß-actin. In conclusion, we show that heterozygous loss-of-function ACTB mutations cause a distinct pleiotropic malformation syndrome with intellectual disability. Our biological studies suggest that a critically reduced amount of this protein alters cell shape, migration, proliferation, and gene expression to the detriment of brain, heart, and kidney development.

Heterogeneity of a Constitutional Complex Chromosomal Rearrangement in 2q.

Complex chromosome rearrangements (CCRs) are unusual structural chromosome alterations found in humans, and to date only a few have been characterized molecularly. New mechanisms, such as chromothripsis, have been proposed to explain the presence of the CCRs in cancer cells and in patients with congenital disorders and/or mental retardation. The aim of the present study was the molecular characterization of a constitutional CCR in a girl with multiple congenital disorders and intellectual disability in order to determine the genotype-phenotype relation and to clarify whether the CCR could have been caused by chromosomal catastrophic events. The present CCR was characterized by G-banding, high-resolution CGH, multiplex ligation-dependent probe amplification and subtelomeric 2q-FISH analyses. Preliminary results indicate that the de novo CCR is unbalanced showing a 2q37.3 deletion and 2q34q37.2 partial trisomy. Our patient shows some of the typical traits and intellectual disability described in patients with 2q37 deletion and also in carriers of 2q34q37.2 partial trisomy; thus, the clinical disorders could be explained by additional effects of both chromosome alterations (deletions and duplications). A posterior, sequential FISH study using BAC probes revealed the unexpected presence of at least 17 different reorganizations affecting 2q34q37.2, suggesting the existence of chromosome instability in this region. The present CCR is the first case described in the literature of heterogeneity of unbalanced CCRs affecting a small region of 2q, indicating that the mechanisms involved in constitutional chromosome rearrangement may be more complex than previously thought.

Clinical course of sly syndrome (mucopolysaccharidosis type VII).

BACKGROUND: Mucopolysaccharidosis VII (MPS VII) is an ultra-rare disease characterised by the deficiency of ß-glucuronidase (GUS). Patients' phenotypes vary from severe forms with hydrops fetalis, skeletal dysplasia and mental retardation to milder forms with fewer manifestations and mild skeletal abnormalities. Accurate assessments on the frequency and clinical characteristics of the disease have been scarce. The aim of this study was to collect such data. METHODS: We have conducted a survey of physicians to document the medical history of patients with MPS VII. The survey included anonymous information on patient demographics, family history, mode of diagnosis, age of onset, signs and symptoms, severity, management, clinical features and natural progression of the disease. RESULTS: We collected information on 56 patients from 11 countries. Patients with MPS VII were classified based on their phenotype into three different groups: (1) neonatal non-immune hydrops fetalis (NIHF) (n=10), (2) Infantile or adolescent form with history of hydrops fetalis (n=13) and (3) Infantile or adolescent form without known hydrops fetalis (n=33). Thirteen patients with MPS VII who had the infantile form with history of hydrops fetalis and survived childhood, had a wide range of clinical manifestations from mild to severe. Five patients underwent bone marrow transplantation and one patient underwent enzyme replacement therapy with recombinant human GUS. CONCLUSIONS: MPS VII is a pan-ethnic inherited lysosomal storage disease with considerable phenotypical heterogeneity. Most patients have short stature, skeletal dysplasia, hepatosplenomegaly, hernias, cardiac involvement, pulmonary insufficiency and cognitive impairment. In these respects it resembles MPS I and MPS II. In MPS VII, however, one unique and distinguishing clinical feature is the unexpectedly high proportion of patients (41%) that had a history of NIHF. Presence of NIHF does not, by itself, predict the eventual severity of the clinical course, if the patient survives infancy.

Interstitial 10p deletion derived from a maternal ins(16;10)(q22;p13p15.2): Report of the first familial case of 10p monosomy affecting to two familial members of different generations.

Monosomy 10p is a rare chromosomal disorder with a prevalence <1/1,000,000, in which a terminal or interstitial distal region of chromosome 10 is deleted resulting in a variable phenotype depending on the size of the deletion. Two main phenotypes have been defined depending on the location of the deletion: HDR syndrome (Hypoparathyroidism, sensorineural Deafness, and Renal disease), and DGS2 (DiGeorge syndrome type 2). The vast majority of cases reported so far have resulted from de novo events. Here, we present the first familial presentation of this contiguous gene deletion syndrome, affecting two family members in different generations: a child and his maternal uncle. In both cases, the deletion was due to a malsegregation of a maternal balanced rearrangement, ins(16;10)(q22;p13p15.2). The identification and characterization of this rearrangement was possible using a combination of different genetic analyses such as karyotype, MLPA, FISH, and array CGH. We underline the importance of the present results in terms of genetic and reproductive counseling for the carriers of the balanced rearrangement within the family, and demonstrate again the utility of expanding the genetic studies to the relatives of the affected patients.

Combinación de acidemia metilmalónica y homocisteinuria; a propósito de un caso / Combined methylmalonic acidemia and homocystinuria; a case report

La combinación de homocistinuria con acidemia metilmalónica es un error congénito del metabolismo de la vitamina B12 o cobalamina. Es una patología poco frecuente de herencia autosómica recesiva en la que existen diversas variantes en función de la patogenia del trastorno metabólico (cblC, cblD, cblF y cblJ). La más frecuente y más grave es la variante cblC, que suele manifestarse en los primeros meses de vida, aunque se han reportado casos al inicio de la edad adulta. Se hace fundamental un correcto diagnóstico y un abordaje terapéutico eficaz. Presentamos el caso clínico de una paciente de 18 años con antecedentes personales de epilepsia que acude por fracaso renal agudo con necesidad de terapia renal sustitutiva diagnosticándose de homocistinuria con acidemia metilmalónica variante cblC (AU)

Combined methylmalonic acidemia and homocystinuria is an inborn error of metabolism of vitamin B12 or cobalamin. It´s a rare autosomal recessive disease in which there are several variants depending on the pathogenesis of the metabolic disorder (cblC, cblD, cblF and cblJ). The more frequent and more severe is the cblC variant, which usually manifests in the first months of life, although some cases have been reported at the beginning of adulthood. A proper diagnosis and effective therapeutic approach is fundamental. We report the case of a patient of 18 years with a history of epilepsy who consults for acute renal failure requiring renal replacement therapy and diagnosed with combined methylmalonic acidemia and homocystinuria cblC variant (AU)

[Combined methylmalonic acidemia and homocystinuria; a case report]. / Combinación de acidemia metilmalónica y homocisteinuria; a propósito de un caso.

Combined methylmalonic acidemia and homocystinuria is an inborn error of metabolism of vitamin B12 or cobalamin. It's a rare autosomal recessive disease in which there are several variants depending on the pathogenesis of the metabolic disorder (cblC, cblD, cblF and cblJ). The more frequent and more severe is the cblC variant, which usually manifests in the first months of life, although some cases have been reported at the beginning of adulthood. A proper diagnosis and effective therapeutic approach is fundamental. We report the case of a patient of 18 years with a history of epilepsy who consults for acute renal failure requiring renal replacement therapy and diagnosed with combined methylmalonic acidemia and homocystinuria cblC variant.

La combinación de homocistinuria con acidemia metilmalónica es un error congénito del metabolismo de la vitamina B12 o cobalamina. Es una patología poco frecuente de herencia autosómica recesiva en la que existen diversas variantes en función de la patogenia del trastorno metabólico (cblC, cblD, cblF y cblJ). La más frecuente y más grave es la variante cblC, que suele manifestarse en los primeros meses de vida, aunque se han reportado casos al inicio de la edad adulta. Se hace fundamental un correcto diagnóstico y un abordaje terapéutico eficaz. Presentamos el caso clínico de una paciente de 18 años con antecedentes personales de epilepsia que acude por fracaso renal agudo con necesidad de terapia renal sustitutiva diagnosticándose de homocistinuria con acidemia metilmalónica variante cblC.

Síndrome cardiofaciocutáneo, un trastorno relacionado con el síndrome de Noonan: hallazgos clínicos y moleculares en 11 pacientes / Cardiofaciocutaneous syndrome, a Noonan syndrome related disorder: Clinical and molecular findings in 11 patients

Objetivos: Describir los hallazgos clínicos y moleculares de 11 pacientes españoles con síndrome cardiofaciocutáneo (CFC), y compararlos con una serie de 130 pacientes con otros trastornos neurocardiofaciocutáneos (111 pacientes con síndrome de Noonan [SN] y 19 con síndrome LEOPARD). Pacientes y métodos: Se obtuvieron datos clínicos de los pacientes remitidos para estudio genético. Se estudiaron los genesPTPN11, SOS1, RAF1, BRAF y MAP2K1 mediante secuenciación bidireccional de los exones donde se localizan las mutaciones más recurrentes, y todos los exones del gen KRAS. Resultados: Se identificaron 6 mutaciones en BRAF en 9 pacientes, y 2 mutaciones en MAP2K1. La talla baja, el retraso psicomotor, los trastornos del lenguaje y las anomalías ectodérmicas fueron más frecuentes en el CFC que en el resto de los síndromes (p < 0,05). En al menos 2 casos el estudio genético contribuyó a reorientar el diagnóstico. Discusión: Los pacientes con CFC muestran un fenotipo más grave, si bien se describe un paciente sin retraso psicomotor, lo que ilustra la variabilidad del espectro fenotípico asociado a las mutaciones en BRAF. El estudio genético es una herramienta útil en el diagnóstico diferencial del CFC y de los trastornos relacionados con el SN (AU)

Objectives: To describe 11 patients with cardiofaciocutaneous syndrome (CFC) and compare them with 130 patients with other RAS-MAPK syndromes (111 Noonan syndrome patients [NS] and 19 patients with LEOPARD syndrome). Patients and methods: Clinical data from patients submitted for genetic analysis were collected. Bidirectional sequencing analysis of PTPN11, SOS1, RAF1, BRAF, and MAP2K1 focused on exons carrying recurrent mutations, and of all KRAS exons were performed. Results: Six different mutations in BRAF were identified in 9 patients, as well as 2 MAP2K1 mutations. Short stature, developmental delay, language difficulties and ectodermal anomalies were more frequent in CFC patients when compared with other neuro-cardio-faciocutaneous syndromes (P < .05). In at least 2 cases molecular testing helped reconsider the diagnosis. Discussion: CFC patients showed a rather severe phenotype but at least one patient with BRAF mutation showed no developmental delay, which illustrates the variability of the phenotypic spectrum caused by BRAFmutations. Molecular genetic testing is a valuable tool for differential diagnosis of CFC and NS related disorders (AU)

[Cardiofaciocutaneous syndrome, a Noonan syndrome related disorder: clinical and molecular findings in 11 patients]. / Síndrome cardiofaciocutáneo, un trastorno relacionado con el síndrome de Noonan: hallazgos clínicos y moleculares en 11 pacientes.

OBJECTIVES: To describe 11 patients with cardiofaciocutaneous syndrome (CFC) and compare them with 130 patients with other RAS-MAPK syndromes (111 Noonan syndrome patients [NS] and 19 patients with LEOPARD syndrome). PATIENTS AND METHODS: Clinical data from patients submitted for genetic analysis were collected. Bidirectional sequencing analysis of PTPN11, SOS1, RAF1, BRAF, and MAP2K1 focused on exons carrying recurrent mutations, and of all KRAS exons were performed. RESULTS: Six different mutations in BRAF were identified in 9 patients, as well as 2 MAP2K1 mutations. Short stature, developmental delay, language difficulties and ectodermal anomalies were more frequent in CFC patients when compared with other neuro-cardio-faciocutaneous syndromes (P<.05). In at least 2 cases molecular testing helped reconsider the diagnosis. DISCUSSION: CFC patients showed a rather severe phenotype but at least one patient with BRAF mutation showed no developmental delay, which illustrates the variability of the phenotypic spectrum caused by BRAF mutations. Molecular genetic testing is a valuable tool for differential diagnosis of CFC and NS related disorders.

Atypical Association of Angelman Syndrome and Klinefelter Syndrome in a Boy with 47,XXY Karyotype and Deletion 15q11.2-q13.

Angelman syndrome (AS, OMIM 105830) is a neurogenetic disorder with firm clinical diagnostic guidelines, characterized by severe developmental delay and speech impairment, balanced and behavioral disturbance as well as microcephaly, seizures, and a characteristic electroencephalogram (EEG). The majority of AS cases (70%) are caused by a 15q11.2-q13 deletion on the maternally derived chromosome. The frequency of AS has been estimated to be between 1/10000 and 1/20000. Klinefelter syndrome (KS) occurs due to the presence of an extra X chromosome (karyotype 47,XXY). The main features in KS are small testes, hypergonadotropic hypogonadism, gynecomastia, learning difficulties, and infertility. We present what is, to our knowledge, the first case of a patient with both KS and AS due to a 15q11.2-q13 deletion on the maternally derived chromosome and an extra X chromosome of paternal origin. He showed dysmorphic features, axial hypotonia, and delayed acquisition of motor skills. Early diagnosis is essential for optimal treatment of AS children; this is one of the earliest diagnosed cases of AS probably due to the presence of two syndromes. Clinical findings in this patient here described may be helpful to identify any other cases and to evaluate recurrence risks in these families.