ISQ as a Diagnostic Tool in Implants Affected with Bone Loss: In Vitro Experimental Study.

PURPOSE: to determine the relationship between bone loss that occurs during the peri-implantitis process and variations in implant stability using resonance frequency analysis measurement methods. MATERIAL & METHODS: 40 self- tapping implants were placed in cow ribs. For each group of 10 implants, a bone loss of 0 mm, 4 mm (simulating 1/3 of bone loss) and 8 mm (simulating 2/3 of bone loss) was established. Osteotomy measurements were made with a periodontal probe. For each implant, RFA was measured using the OSSTELL BEACON system by the same operator. RESULTS: The initial ISQ value of the 40 implants placed exceeded values of 70, reflecting an average of 73 in the VL direction and 74.8 in the MD direction. ISQ measurements in the 10 implants in which bone dehiscence was performed on the vestibular aspect reflected a decrease in ISQ values as bone loss deepens. When generating bone loss in two opposite faces (V and L), a greater decrease in ISQ values was observed when 2/3 of the implant were affected. The average value of the measurements in the VL direction was less than 70 when the loss is 2/3. CONCLUSIONS: when bone loss occurs on only one side of the implant, the ISQ values decrease,but the implant maintains good stability. The same occurs when two opposite sides of the implant are affected, the unaffected side has the least decrease in ISQ value.

Engineering bio-brick protein scaffolds for organizing enzyme assemblies.

Enzyme scaffolding is an emerging approach for enhancing the catalytic efficiency of multi-enzymatic cascades by controlling their spatial organization and stoichiometry. This study introduces a novel family of engineered SCAffolding Bricks, named SCABs, utilizing the consensus tetratricopeptide repeat (CTPR) domain for organized multi-enzyme systems. Two SCAB systems are developed, one employing head-to-tail interactions with reversible covalent disulfide bonds, the other relying on non-covalent metal-driven assembly via engineered metal coordinating interfaces. Enzymes are directly fused to SCAB modules, triggering assembly in a non-reducing environment or by metal presence. A proof-of-concept with formate dehydrogenase (FDH) and L-alanine dehydrogenase (AlaDH) shows enhanced specific productivity by 3.6-fold compared to free enzymes, with the covalent stapling outperforming the metal-driven assembly. This enhancement likely stems from higher-order supramolecular assembly and improved NADH cofactor regeneration, resulting in more efficient cascades. This study underscores the potential of protein engineering to tailor scaffolds, leveraging supramolecular spatial-organizing tools, for more efficient enzymatic cascade reactions.

ITPR1-associated spinocerebellar ataxia with craniofacial features-additional evidence for germline mosaicism.

Inositol 1,4,5-triphosphate receptor type 1 (ITPR1) is an endoplasmic reticulum-bound intracellular inositol triphosphate receptor involved in the regulation of intracellular calcium. Pathogenic variants in ITPR1 are associated with spinocerebellar ataxia (SCA) types 15/16 and 29 and have recently been implicated in a facial microsomia syndrome. In this report, we present a family with three affected individuals found to have a heterozygous missense c.800C > T (predicted p.Thr267Met) who present clinically with a SCA29-like syndrome. All three individuals presented with varying degrees of ataxia, developmental delay, and apparent intellectual disability, as well as craniofacial involvement-an uncommon finding in patients with SCA29. The variant was identified using clinical exome sequencing and validated with Sanger sequencing. It is presumed to be inherited via parental germline mosaicism. We present our findings to provide additional evidence for germline mosaic inheritance of SCA29, as well as to expand the clinical phenotype of the syndrome.

Emerging and Novel Viruses in Passerine Birds.

There is growing interest in emerging viruses that can cause serious or lethal disease in humans and animals. The proliferation of cloacal virome studies, mainly focused on poultry and other domestic birds, reveals a wide variety of viruses, although their pathogenic significance is currently uncertain. Analysis of viruses detected in wild birds is complex and often biased towards waterfowl because of the obvious interest in avian influenza or other zoonotic viruses. Less is known about the viruses present in the order Passeriformes, which comprises approximately 60% of extant bird species. This review aims to compile the most significant contributions on the DNA/RNA viruses affecting passerines, from traditional and metagenomic studies. It highlights that most passerine species have never been sampled. Especially the RNA viruses from Flaviviridae, Orthomyxoviridae and Togaviridae are considered emerging because of increased incidence or avian mortality/morbidity, spread to new geographical areas or hosts and their zoonotic risk. Arguably poxvirus, and perhaps other virus groups, could also be considered "emerging viruses". However, many of these viruses have only recently been described in passerines using metagenomics and their role in the ecosystem is unknown. Finally, it is noteworthy that only one third of the viruses affecting passerines have been officially recognized.

903 Protein Saver cards: the best alternative for dried blood spot storage at room temperature for HCV RNA.

Hepatitis C virus (HCV) infection remains a global health problem, detected only in the early stages by molecular tests. Molecular tests detect HCV RNA, which is very prone to degradation by ribonucleases, reason why blood samples must be transported and stored at - 20 °C, or even - 70 °C for long-term storage. Flinders Technology Associates (FTA) cards are a useful sampling collecting device for dry blood spot (DBS) storage, especially for low and middle-income countries (LMIC). In this study, we analyzed viral HCV RNA integrity for long-term storage at room temperature compared to - 20 °C using two different types of cards for DBS: FTA Classic and 903 Protein Saver cards. For this purpose, DBS were prepared on these cards using blood or plasma samples from HCV infected patients, and samples were analysed by conventional RT-PCR. Our results showed that 903 Protein Saver cards are the best and cheapest alternative for DBS storage at room temperature. In these conditions, we found that HCV RNA integrity lasted for up to 9 months.

African swine fever virus ubiquitin-conjugating enzyme pI215L inhibits IFN-I signaling pathway through STAT2 degradation.

African swine fever virus (ASFV) is the causative agent of one of the most lethal diseases affecting domestic pig and wild boar, which is endangering the swine industry due to its rapid expansion. ASFV has developed different mechanisms to evade the host immune response, including inhibition of type I IFN (IFN-I) production and signaling, since IFN-I is a key element in the cellular antiviral response. Here, we report a novel mechanism of evasion of the IFN-I signaling pathway carried out by the ASFV ubiquitin-conjugating enzyme pI215L. Our data showed that pI215L inhibited IFN-stimulated response element (ISRE) activity and the consecutive mRNA induction of the IFN-stimulated genes ISG15 and IFIT1 through the ubiquitination and proteasomal degradation of STAT2. Additionally, by immunofluorescence, co-immunoprecipitation and nucleus-cytoplasm fractionation approaches, we have confirmed the interaction and colocalization of STAT2 and pI215L, in ectopic experiments and during ASFV infection. Moreover, expression of the catalytic mutant (I215L-C85A) did not inhibit the induction of ISG15 and IFIT1, nor the activity of ISRE. Furthermore, we confirmed that STAT2 degradation by pI215L is dependent on its catalytic activity, since expression of the pI215L-C85A mutant did not affect STAT2 levels, compared to the wild-type protein. Yet, our data reveal that the interaction of pI215L with STAT2 does not require the integrity of its catalytic domain since the pI215L-C85A mutant co-immunoprecipitates with STAT2. All these findings reveal, for the first time, the involvement of E2-ubiquitin-conjugating enzyme activity of pI215L in the immune response modulation.

Persistent low-Level viremia in persons living with HIV undertreatment: An unresolved status.

Antiretroviral therapy (ART) allows suppressed viremia to reach less than 50 copies/mL in most treated persons living with HIV (PLWH). However, the existence of PLWH that show events of persistent low-level viremia (pLLV) between 50 and 1000 copies/mL and with different virological consequences have been observed. PLLV has been associated with higher virological failure (VF), viral genotype resistance, adherence difficulties and AIDS events. Moreover, some reports show that pLLV status can lead to residual immune activation and inflammation, with an increased risk of immunovirological failure and a pro-inflammatory cytokine level which can lead to a higher occurrence of non-AIDS defining events (NADEs) and other adverse clinical outcomes. Until now, however, published data have shown controversial results that hinder understanding of the true cause(s) and origin(s) of this phenomenon. Molecular mechanisms related to viral reservoir size and clonal expansion have been suggested as the possible origin of pLLV. This review aims to assess recent findings to provide a global view of the role of pLLV in PLWH and the impact this status may cause on the clinical progression of these patients.

Zika Virus Pathogenesis: A Battle for Immune Evasion.

Zika virus (ZIKV) infection and its associated congenital and other neurological disorders, particularly microcephaly and other fetal developmental abnormalities, constitute a World Health Organization (WHO) Zika Virus Research Agenda within the WHO's R&D Blueprint for Action to Prevent Epidemics, and continue to be a Public Health Emergency of International Concern (PHEIC) today. ZIKV pathogenicity is initiated by viral infection and propagation across multiple placental and fetal tissue barriers, and is critically strengthened by subverting host immunity. ZIKV immune evasion involves viral non-structural proteins, genomic and non-coding RNA and microRNA (miRNA) to modulate interferon (IFN) signaling and production, interfering with intracellular signal pathways and autophagy, and promoting cellular environment changes together with secretion of cellular components to escape innate and adaptive immunity and further infect privileged immune organs/tissues such as the placenta and eyes. This review includes a description of recent advances in the understanding of the mechanisms underlying ZIKV immune modulation and evasion that strongly condition viral pathogenesis, which would certainly contribute to the development of anti-ZIKV strategies, drugs, and vaccines.

Early-onset cerebellar ataxia in a patient with CMT2A2.

A 9-yr 8-mo-old right-handed female presented with a history of gait difficulties, which first became apparent at age 9 mo of age, along with slurred speech and hand tremors while holding a tray. Her past medical history was significant for global developmental delay, and she was attending fourth grade special education classes. On examination, she had an ataxic gait, dysarthria, absent deep tendon reflexes, and flexor plantar responses. There were no signs of optic atrophy or hearing loss. Nerve conduction studies were consistent with an axonal neuropathy. A fascicular sural nerve biopsy showed a marked decrease of myelinated fibers larger than 6 µm in diameter as compared with an age-matched control. By electron microscopy, clusters of degenerating axonal mitochondria in both myelinated and unmyelinated fibers were frequently found. Whole-exome sequencing revealed a heterozygous c.314C > T (p.Thr105Met) missense variant in MFN2 in the patient but not in her mother. The father was unavailable for testing. The phenotypes with MFN2 variants can be quite variable, including intellectual disability, optic atrophy, auditory impairment, spinal atrophy with or without hydromyelia, and hydrocephalus. We report here that early onset ataxia with intellectual disability can also be associated with MFN2-related Charcot-Marie-Tooth, Type 2A2A diagnosis, the most common type of autosomal dominant axonal neuropathy.

Nanotechnology: A reality for diagnosis of HCV infectious disease.

Hepatitis C virus (HCV) is the primary etiologic agent of liver cirrhosis or hepatocellular carcinoma. HCV elevated infection rates are mostly due to the lack of an accurate and accessible screening and diagnosis, especially in low- and middle-income countries. Conventional HCV diagnostic algorithm consists of a serological test followed by a nucleic acid test. This sequence of tests is time consuming and not affordable for low-resource settings. Nanotechnology have introduced new promising tests for the diagnose of infectious diseases. Based on the employment of nanoparticles and other nanomaterials which lead to highly sensitive and specific nanoscale tests, most of them target pathogen genome. Implementation of nanoscale tests, which are affordable, portable and easy to use by non-specialized personal, would improve HCV diagnosis algorithm. In this review, we have summed up the current emerging nanotechnology tools, which will improve actual screening and treatment programs, and help to reach HCV elimination proposal.

HIV-1 Nef Targets HDAC6 to Assure Viral Production and Virus Infection.

HIV Nef is a central auxiliary protein in HIV infection and pathogenesis. Our results indicate that HDAC6 promotes the aggresome/autophagic degradation of the viral polyprotein Pr55Gag to inhibit HIV-1 production. Nef counteracts this antiviral activity of HDAC6 by inducing its degradation and subsequently stabilizing Pr55Gag and Vif viral proteins. Nef appears to neutralize HDAC6 by an acidic/endosomal-lysosomal processing and does not need the downregulation function, since data obtained with the non-associated cell-surface Nef-G2A mutant - the cytoplasmic location of HDAC6 - together with studies with chemical inhibitors and other Nef mutants, point to this direction. Hence, the polyproline rich region P72xxP75 (69-77 aa) and the di-Leucin motif in the Nef-ExxxLL160-165 sequence of Nef, appear to be responsible for HDAC6 clearance and, therefore, required for this novel Nef proviral function. Nef and Nef-G2A co-immunoprecipitate with HDAC6, whereas the Nef-PPAA mutant showed a reduced interaction with the anti-HIV-1 enzyme. Thus, the P72xxP75 motif appears to be responsible, directly or indirectly, for the interaction of Nef with HDAC6. Remarkably, by neutralizing HDAC6, Nef assures Pr55Gag location and aggregation at plasma membrane, as observed by TIRFM, promotes viral egress, and enhances the infectivity of viral particles. Consequently, our results suggest that HDAC6 acts as an anti-HIV-1 restriction factor, limiting viral production and infection by targeting Pr55Gag and Vif. This function is counteracted by functional HIV-1 Nef, in order to assure viral production and infection capacities. The interplay between HIV-1 Nef and cellular HDAC6 may determine viral infection and pathogenesis, representing both molecules as key targets to battling HIV.

VAC14 syndrome in two siblings with retinitis pigmentosa and neurodegeneration with brain iron accumulation.

Whole-exome sequencing was used to identify the genetic etiology of a rapidly progressing neurological disease present in two of six siblings with early childhood onset of severe progressive spastic paraparesis and learning disabilities. A homozygous mutation (c.2005G>T, p, V669L) was found in VAC14, and the clinical phenotype is consistent with the recently described VAC14-related striatonigral degeneration, childhood-onset syndrome (SNDC) (MIM#617054). However, the phenotype includes a distinct clinical presentation of retinitis pigmentosa (RP), which has not previously been reported in association with VAC14 mutations. Brain magnetic resonance imaging (MRI) revealed abnormal magnetic susceptibility in the globus pallidus, which can be seen in neurodegeneration with brain iron accumulation (NBIA). RP is a group of inherited retinal diseases with phenotypic/genetic heterogeneity, and the pathophysiologic basis of RP is not completely understood but is thought to be due to a primary retinal photoreceptor cell degenerative process. Most cases of RP are seen in isolation (nonsyndromic); this is a report of RP in two siblings with VAC14-associated syndrome, and it is suggested that a connection between RP and VAC14-associated syndrome should be explored in future studies.

Assessment of Dental Implants with Modified Calcium-Phosphate Surface in a Multicenter, Prospective, Non-Interventional Study: Results up to 50 Months of Follow-Up.

Prescription of implant treatments is very widespread at present, mainly due to the low rate of annual loss and, to date, few studies have assessed their survival in the routine clinical practice of dentistry. The purpose of this observational study was to evaluate the effectiveness of dental implants with a calcium-phosphate surface in the daily practice of dental clinics. A multicenter, prospective, non-interventional, observational study was performed, in which three experienced practitioners (one maxillofacial and two oral surgeons) inserted implants using standard external and internal hexagon connections in adult patients requiring ≥1 osseointegrated implants to replace missing teeth. Follow-up was performed for 24 months after implant loading. Two hundred and twelve subjects were included (51.5% men), with a mean age of 51.2 ± 11.90 years, in whom 544 implants were inserted. 87.2% of the patients received 1⁻4 implants. The preferred connection system was internal hexagon (73.5%). There were nine failures, with an interval survival rate (ISR) at 24 months of 100% and a cumulative survival rate (CSR) of 98.3%. In conclusion, implants with a modified calcium-phosphate surface are associated with a high rate of survival and may be considered a method of choice in clinical practice.

[Spirometric caracterization of cystic fibrosis patients]. / Caracterización espirométrica de pacientes con fibrosis quística.

INTRODUCTION: The prognosis of patients with cystic fibrosis (CF) has remarkably improved. The as sessment of the disease progression is based on the measurement of the FEV1 (Forced Expiratory Volume in one second). OBJECTIVES: 1. To describe forced expiratory flows and volumes and com pare their interpretation according to different reference standards (Knudson, Gutiérrez, and multi ethnic GLI); 2. To describe bronchodilator response. PATIENTS AND METHOD: The medical records and spirometries of all patients with CF controlled at the Dr. Sotero del Rio Hospital were reviewed. Demographic background, sweat test results, genetic study , and bacteriological study were obtained. In addition, Forced Vital Capacity (FVC) was recorded as well as FEV1 and FEV1/FVC ratio. Re sults: Data from 14 patients, were analyzed, seven males, aged 6-24 years, median 15 years, median BMI 18.15 (range 14.6-23.3), median sweat chloride test 76 mEq/l (range 50,2-119 mEq/l), seven patients with at least one F508del mutation. Using multi-ethnic and Gutierrez predictive formulas, lung function involvement occurred previously in relation to the use of Knudson equations. None of the patients had a significant bronchodilator response. CONCLUSION: The group of patients descri bed mostly presents functional respiratory involvement and had no bronchodilator response. The interpretation of functional respiratory involvement varies according to the theoretical values used.

Caracterización espirométrica de pacientes con fibrosis quística / Spirometric caracterization of cystic fibrosis patients

INTRODUCCIÓN: El pronóstico de los pacientes con fibrosis quística (FQ) ha mejorado en forma notable. La evaluación de la progresión de la enfermedad se basa en la medición del Volumen Espirado al primer segundo (VEF1). OBJETIVOS: 1. Describir volúmenes y flujos espiratorios forzados y comparar su interpretación según diferentes patrones de referencia (Knudson, multiétnicas Global Lung Initiative, Gutiérrez); 2. Comparar evolución de VEF1 según diferentes patrones de referencia; 3. Describir respuesta a broncodilatador. PACIENTES Y MÉTODO: Estudio retrospectivo de fichas clínicas y espirometrías de pacientes con FQ controlados en Hospital Dr. Sótero del Río. Se obtuvo antecedentes demográficos, resultados de prueba de sudor, estudio genético, estudio bacteriológico. Se evaluó respuesta a broncodilatador (salbutamol 400 ugr), considerando significativo un aumento en 12% en el VEF1. El valor de cloro en sudor se obtuvo mediante método de Gibson y Cooke. Se registraron: Capacidad Vital Forzada (CVF), Volumen Espirado al primer segundo (VEF1) y relación VEF1/CVF. Para graficar la progresión del VEF1 en el tiempo y las curvas teóricas de GLI, Knudson y Gutiérrez, se utilizó el software de libre distribución R versión 3.3.1. RESULTADOS: Se incluyeron 14 pacientes, 7 varones, edad entre 6 y 24 años, mediana 15 años, me diana índice de masa corporal (IMC) 18,15 (rango 14,6-23,3), mediana cloro en sudor 76 mEq/l (rango 50,2- 119), 7 pacientes con al menos 1 mutación F508del. Al utilizar fórmulas predictivas multiétnicas y de Gutiérrez, el compromiso de la función pulmonar ocurría con anterioridad en relación al uso de ecuaciones de Knudson. Ninguno de los pacientes presentó respuesta significativa a broncodilatador. CONCLUSIÓN: El grupo de pacientes descritos presenta en su mayoría compromiso funcional respiratorio y no tiene respuesta a broncodilatador. La interpretación del compromiso funcional respiratorio varía según los valores teóricos utilizados.

INTRODUCTION: The prognosis of patients with cystic fibrosis (CF) has remarkably improved. The as sessment of the disease progression is based on the measurement of the FEV1 (Forced Expiratory Volume in one second). OBJECTIVES: 1. To describe forced expiratory flows and volumes and com pare their interpretation according to different reference standards (Knudson, Gutiérrez, and multi ethnic GLI); 2. To describe bronchodilator response. Patients and Method: The medical records and spirometries of all patients with CF controlled at the Dr. Sotero del Rio Hospital were reviewed. Demographic background, sweat test results, genetic study , and bacteriological study were obtained. In addition, Forced Vital Capacity (FVC) was recorded as well as FEV1 and FEV1/FVC ratio. RESULTS: Data from 14 patients, were analyzed, seven males, aged 6-24 years, median 15 years, median BMI 18.15 (range 14.6-23.3), median sweat chloride test 76 mEq/l (range 50,2-119 mEq/l), seven patients with at least one F508del mutation. Using multi-ethnic and Gutierrez predictive formulas, lung function involvement occurred previously in relation to the use of Knudson equations. None of the patients had a significant bronchodilator response. CONCLUSION: The group of patients descri bed mostly presents functional respiratory involvement and had no bronchodilator response. The interpretation of functional respiratory involvement varies according to the theoretical values used.

A Conserved GPG-Motif in the HIV-1 Nef Core Is Required for Principal Nef-Activities.

To find out new determinants required for Nef activity we performed a functional alanine scanning analysis along a discrete but highly conserved region at the core of HIV-1 Nef. We identified the GPG-motif, located at the 121-137 region of HIV-1 NL4.3 Nef, as a novel protein signature strictly required for the p56Lck dependent Nef-induced CD4-downregulation in T-cells. Since the Nef-GPG motif was dispensable for CD4-downregulation in HeLa-CD4 cells, Nef/AP-1 interaction and Nef-dependent effects on Tf-R trafficking, the observed effects on CD4 downregulation cannot be attributed to structure constraints or to alterations on general protein trafficking. Besides, we found that the GPG-motif was also required for Nef-dependent inhibition of ring actin re-organization upon TCR triggering and MHCI downregulation, suggesting that the GPG-motif could actively cooperate with the Nef PxxP motif for these HIV-1 Nef-related effects. Finally, we observed that the Nef-GPG motif was required for optimal infectivity of those viruses produced in T-cells. According to these findings, we propose the conserved GPG-motif in HIV-1 Nef as functional region required for HIV-1 infectivity and therefore with a potential interest for the interference of Nef activity during HIV-1 infection.

CD2v Interacts with Adaptor Protein AP-1 during African Swine Fever Infection.

African swine fever virus (ASFV) CD2v protein is believed to be involved in virulence enhancement, viral hemadsorption, and pathogenesis, although the molecular mechanisms of the function of this viral protein are still not fully understood. Here we describe that CD2v localized around viral factories during ASFV infection, suggesting a role in the generation and/or dynamics of these viral structures and hence in disturbing cellular traffic. We show that CD2v targeted the regulatory trans-Golgi network (TGN) protein complex AP-1, a key element in cellular traffic. This interaction was disrupted by brefeldin A even though the location of CD2v around the viral factory remained unchanged. CD2v-AP-1 binding was independent of CD2v glycosylation and occurred on the carboxy-terminal part of CD2v, where a canonical di-Leu motif previously reported to mediate AP-1 binding in eukaryotic cells, was identified. This motif was shown to be functionally interchangeable with the di-Leu motif present in HIV-Nef protein in an AP-1 binding assay. However, we demonstrated that it was not involved either in CD2v cellular distribution or in CD2v-AP-1 binding. Taken together, these findings shed light on CD2v function during ASFV infection by identifying AP-1 as a cellular factor targeted by CD2v and hence elucidate the cellular pathways used by the virus to enhance infectivity.

Biopsy in a patient with PMP22 exon 2 mutation recapitulates pathology of Trembler-J mouse.

We describe a patient with a longstanding history of hypertrophic neuropathy of Dejerine-Sottas type, ultimately diagnosed with CMT1E disease due to a new p.Leu18Arg missense mutation in the first transmembrane domain of the PMP22 gene. The patient never walked independently and was wheelchair bound by age 18 years. Her parents and son were unaffected. Her peroneal muscular atrophy syndrome presented with scoliosis, bilateral hearing loss, pes planus, distal sensory loss and generalized areflexia. A nerve biopsy at age 26 years showed nerve hypertrophy, myelin uncompaction, defects in mesaxon formation, Schwann cells with irregular outline, axons incompletely surrounded by Schwann cell processes and very short internodes interspersed with denuded axons. Large, mostly denervated, onion bulb formations were also prominent. These findings indicate that demyelination continues undeterred in the advanced stages of the disease and is followed by remyelination attempts that recapitulate the early defects in Schwann cell/axon interaction seen in the Trembler-J mouse, which carries a mutation in the same transmembrane domain.

Dysmorphic features, cognitive disability, chronic inflammation, and predisposition to vascular disease in two sisters: a new autosomal recessive disorder?

A 20-year-old woman presented with mental retardation and a history of stroke related to moyamoya disease at the age of 8 years. She had cognitive impairment which became more pronounced after the stroke. This patient's parents were first cousins and six close family relatives had strokes in their 60s or 70s. The patient's 16-year-old sister had learning disability, chronic muscle pain, and an ECG suggestive of previous hypoxemic heart injury. The two sisters had similar dysmorphic facial appearance including a prominent philtrum, bulbous nose, and severe acne. They both had increased subcutaneous tissue in their faces, whereas their bodies were slim. Both sisters were found to have elevated levels of rheumatoid factor, C-reactive protein, and erythrocyte sedimentation rate on repeat measurements. Partial autoimmunity screening in one of the patients was negative. Chromosome analysis and array comparative genomic hybridization analyses were also normal. Nerve conduction findings in the younger sister were consistent with distal, predominantly motor, demyelinating neuropathy localized to the lower extremities. We propose that these two sisters suffer from a new autosomal recessive syndrome. Carrier status for this condition may predispose to later onset stroke.

Genetic spectrum of hereditary neuropathies with onset in the first year of life.

Early onset hereditary motor and sensory neuropathies are rare disorders encompassing congenital hypomyelinating neuropathy with disease onset in the direct post-natal period and Dejerine-Sottas neuropathy starting in infancy. The clinical spectrum, however, reaches beyond the boundaries of these two historically defined disease entities. De novo dominant mutations in PMP22, MPZ and EGR2 are known to be a typical cause of very early onset hereditary neuropathies. In addition, mutations in several other dominant and recessive genes for Charcot-Marie-Tooth disease may lead to similar phenotypes. To estimate mutation frequencies and to gain detailed insights into the genetic and phenotypic heterogeneity of early onset hereditary neuropathies, we selected a heterogeneous cohort of 77 unrelated patients who presented with symptoms of peripheral neuropathy within the first year of life. The majority of these patients were isolated in their family. We performed systematic mutation screening by means of direct sequencing of the coding regions of 11 genes: MFN2, PMP22, MPZ, EGR2, GDAP1, NEFL, FGD4, MTMR2, PRX, SBF2 and SH3TC2. In addition, screening for the Charcot-Marie-Tooth type 1A duplication on chromosome 17p11.2-12 was performed. In 35 patients (45%), mutations were identified. Mutations in MPZ, PMP22 and EGR2 were found most frequently in patients presenting with early hypotonia and breathing difficulties. The recessive genes FGD4, PRX, MTMR2, SBF2, SH3TC2 and GDAP1 were mutated in patients presenting with early foot deformities and variable delay in motor milestones after an uneventful neonatal period. Several patients displaying congenital foot deformities but an otherwise normal early development carried the Charcot-Marie-Tooth type 1A duplication. This study clearly illustrates the genetic heterogeneity underlying hereditary neuropathies with infantile onset.