Increased enhancer-promoter interactions during developmental enhancer activation in mammals.

Remote enhancers are thought to interact with their target promoters via physical proximity, yet the importance of this proximity for enhancer function remains unclear. Here we investigate the three-dimensional (3D) conformation of enhancers during mammalian development by generating high-resolution tissue-resolved contact maps for nearly a thousand enhancers with characterized in vivo activities in ten murine embryonic tissues. Sixty-one percent of developmental enhancers bypass their neighboring genes, which are often marked by promoter CpG methylation. The majority of enhancers display tissue-specific 3D conformations, and both enhancer-promoter and enhancer-enhancer interactions are moderately but consistently increased upon enhancer activation in vivo. Less than 14% of enhancer-promoter interactions form stably across tissues; however, these invariant interactions form in the absence of the enhancer and are likely mediated by adjacent CTCF binding. Our results highlight the general importance of enhancer-promoter physical proximity for developmental gene activation in mammals.

Rapid and Quantitative Functional Interrogation of Human Enhancer Variant Activity in Live Mice.

Functional analysis of non-coding variants associated with human congenital disorders remains challenging due to the lack of efficient in vivo models. Here we introduce dual-enSERT, a robust Cas9-based two-color fluorescent reporter system which enables rapid, quantitative comparison of enhancer allele activities in live mice of any genetic background. We use this new technology to examine and measure the gain- and loss-of-function effects of enhancer variants linked to limb polydactyly, autism, and craniofacial malformation. By combining dual-enSERT with single-cell transcriptomics, we characterize variant enhancer alleles at cellular resolution, thereby implicating candidate molecular pathways in pathogenic enhancer misregulation. We further show that independent, polydactyly-linked enhancer variants lead to ectopic expression in the same cell populations, indicating shared genetic mechanisms underlying non-coding variant pathogenesis. Finally, we streamline dual-enSERT for analysis in F0 animals by placing both reporters on the same transgene separated by a synthetic insulator. Dual-enSERT allows researchers to go from identifying candidate enhancer variants to analysis of comparative enhancer activity in live embryos in under two weeks.

Dihydropteridine Reductase Deficiency - A Rare and Potentially Treatable Cause Mimicking Cerebral Palsy.

INTRODUCTION: Dihydropteridine reductase deficiency (DHPRD) is a rare genetic disorder of tetrahydrobiopterin (BH4) regeneration, a cofactor for several enzymes, including phenylalanine hydroxylase. Due to hyperphenylalaninemia (HPA), patients can be detected by the newborn metabolic screening, when available. The most common symptoms of DHPRD may mimic cerebral palsy: developmental/cognitive impairment, hypotonia, peripheral hypertonia, dystonia, feeding difficulties, epilepsy, and microcephaly. The long-term neurodevelopmental outcome is strongly influenced by the early initiation of effective treatment. CASE REPORT: A 2-year-old boy, born in Guinea, was evaluated in our center with the diagnosis of "cerebral palsy". He was born after a prolonged labor, and had feeding difficulties and severe developmental delay. Examination revealed microcephaly, axial hypotonia, and dyskinetic movements without hypertension. No seizures or oculogyric crisis were reported. Brain MRI showed slight brain atrophy and hyperintensity T2/FLAIR in basal ganglia. The diagnosis of cerebral palsy was questioned, and further investigation was carried out. HPA raised the possibility of BH4 deficiency, supported by increased biopterin in urine, decreased neurotransmitters in CSF, and low DHPR enzyme activity. A variant (128_130del (p.(Val43del)) in apparent homozygosity was later detected in the QPDR gene. At 4 years old, he started L-dopa/carbidopa, oxitriptan, and a phenylalanine-restrictive diet with moderate clinical improvement. CONCLUSION: When the diagnosis of "cerebral palsy" is questionable, other etiologies should be investigated, particularly disorders that have specific disease-modifying treatment. In our patient, the atypical constellation of neurological signs, brain MRI findings, and the nonexistence of newborn metabolic screening in the country of origin supported additional investigation. The presence of HPA-associated dystonia was crucial to the investigation and was later confirmed as DHPRD. Unfortunately, at this stage, the reversibility of the neurological damage in response to treatment is doubtful.

Metabolic Myopathies: Experience of a Reference Center of Inherited Metabolic Diseases.

INTRODUCTION: Metabolic myopathies (MM) are a heterogeneous group of genetic disorders affecting metabolic pathways involved in energy production during rest, exercise and physiologic stress (fever, fasting, …). Impairments in the pathways of glycolysis/ glycogenolysis, fatty acid transport/oxidation or in the mitochondrial respiratory chain present primarily with exercise intolerance, myalgias, weakness, cramps, or rhabdomyolysis. Depending on aetiology, the diagnosis can be made through neonatal screening, pre-symptomatic or in the set of clinical manifestations for which a high level of suspicion is important. METHODS: Retrospective descriptive study of the clinical, biochemical, and molecular features of patients with a confirmed diagnosis of MM followed by the multidisciplinary team of the Reference Center of Inherited Metabolic Diseases of Centro Hospitalar Universitário de Lisboa Central from 2009 to 2022. RESULTS: Twenty-three patients with MM were included: 9 (39%) glycogen storage diseases (7 McArdle and 2 Pompe), 7 (30%) fatty acid oxidation disorders (3 CPT2, 3 LCHAD and 1 MAD deficiencies), 6 (26%) mitochondrial disease with significant muscle involvement (2 Pearson, 1 Kearns Sayre, 1 VARS2, 1 SUCLA2 and 1 MT-TL1 deficiencies), and 1 myoadenylate deaminase deficiency. Ages varied from 15 months to 35 years. Eighteen (78%) patients were diagnosed by clinical symptoms, 3 by newborn screening (LCHAD) and 2 were asymptomatic (1 Pompe and 1 McArdle). Frequent symptoms were rhabdomyolysis triggered by illness or exercise 12 (52%), fatigue 11 (48%), exercise intolerance 10 (43%), and myalgia 9 (43%). Eight (35%) patients (LCHAD and mitochondrial) had multisystemic involvement. In 20 (87%) patients, the diagnosis was confirmed by biochemical and/or genetic analysis and 3 (McArdle) by muscle biopsy. CONCLUSION: MM are a heterogeneous set of disorders, but a careful history may guide the differential diagnosis among biochemical pathways and other etiologies. Nowadays, molecular testing has become a powerful tool for diagnosis confirmation, surpassing muscular biopsy in most cases. Accurate diagnosis is important to identify who may benefit from specific therapeutic options, such as enzyme replacement therapy, restricted diets, emergency regime and cofactors. All patients benefit from adequate lifestyle modifications, individualized exercise prescription, nutritional intervention, and genetic counselling.

Clinical, Biochemical and Molecular Features of a Cohort of 8 Patients with Inherited Disorders of Vitamin B12 Metabolism in a Metabolic Reference Center.

BACKGROUND: Vitamin B12, or cobalamin (Cbl), undergoes a complex series of absorptive and intracellular processing steps before serving as a cofactor for the enzymes methylmalonyl-CoA mutase and methionine synthase. Disorders of intracellular cobalamin metabolism have variable phenotypes and age of onset related to the location of the defect in the metabolic pathway leading to a combined methylmalonic acidemia and homocystinuria (cblC, cblD, cblF and cblJ), Isolated methylmalonic acidemia (cblA, cblB and cblDv2) and isolated homocystinuria (cblDv1, cblE and cblG). OBJECTIVE AND METHODS: We conducted a retrospective study of the clinical biochemical and molecular features of a cohort of patients with disorders of intracellular Cbl metabolism followed in our Reference Centre of Inherited Metabolic Diseases (CR-IMD) for the last 23 years (2000-2023). RESULTS: CblC: P1 and P2, pré-newborn screening (NBS), had an early and severe presentation evolving to multiorgan failure and death. P3 was asymptomatic at NBS with an excellent evolution except for nystagmus and retinitis pigmentosa. P4 presented at 19Y with an atypical hemolytic uremic syndrome and is presently on hemodialysis. CblD: P5 had a developmental delay (DD) and hypotonia and presented at 14m with seizures. CblDv2: P6 had DD and failure to thrive (FTT) and presented at 4Y with acute metabolic acidosis. CblDv1: P7 had DD, FTT, and hypotonia and presented at 16m with seizures and anemia. CblG: P8 had DD and FTT and presented at 15m with macrocytic anemia. In all, characteristic biochemical profiles guided the diagnosis, afterward confirmed by genetic analysis (4 MMACHC, 3 MMADHC, 1 MTR). All patients received either betaine, hydroxycobalamin, or both (P3 is on a very high dosage). CONCLUSION: Our cohort of patients has similar clinical and biochemical characteristics to the ones described in the literature. Outcomes of patients reinforce the importance of newborn screening and the need for consensus guidelines for optimal doses of parenteral hydroxocobalamin.

Diversities in Leigh Syndrome Associated with MT-ATP6 Gene Variants.

INTRODUCTION: Leigh syndrome (LS) is clinically and genetically heterogeneous and presents defective mitochondrial bioenergetics. Patients present neurological symptoms and imagiological features that may result in early death [1]. The LS has been associated with mitochondrial DNA (mtDNA) variants, e.g., m.8993T>G (L156R) and m.8993T>C (L156P), in the MT-ATP6 gene. They lead to the substitution of a highly conserved amino acid in subunit 6 of ATP synthase, affecting the F0 domain and ATP synthesis [1-3]. We present five cases with m.8993T>G and a family harbouring m.8993T>C+m.1555A>G (proband and four relatives). METHODS: Our laboratory received 48 samples from LS-suspected patients. The samples (various tissues) were assessed for bioenergetics (activity of mitochondrial respiratory chain (MRC) complexes, ubiquinone content) and genetic analyses (mtDNA copy number, Sequencing and PCR-RFLP) by established protocols. RESULTS/CASE REPORT: Bioenergetics were assessed in 5 patients (various tissues) with varying levels of MRC/ATP synthase impairment. Six cases had a mtDNA pathogenic variant in the 8993 nucleotide associated with LS. Five cases presented the m.8993T>G variant, one of which (P5) possibly de novo. This variant was homoplasmy (P1-3) or very high heteroplasmy (P4/5, 90-95%). Of the four patients with bioenergetics assessment, three (P1/3/4) had deficiencies of MRC complexes, and P5 had small deficits. The other case (familial, proband and 4 relatives) presented a combination of m.1555A>G (homoplasmy) and m.8993T>C (heteroplasmy) variants. The proband presents m.8993T>C in 95% heteroplasmy and 85-35% in three relatives. All have m.1555A>G in homoplasmy, including the fourth relative without m.8993T>C. A deficiency (31%) was found in complex V activity in muscle for proband. CONCLUSION: We present a case series of patients harbouring pathogenic variants in the 8993 nucleotide of mtDNA, which have been associated with LS and impairment of MRC's complex V. These cases highlight the variability in clinical symptoms and their severity, as well as genetic heterogeneity within LS. Many patients will not present a classic pathogenic variant and there are many cases of asymptomatic relatives (carriers). It is important to get a broader view of the cases - classical methods and multiple tissue analysis are still valuable tools for the comprehensive characterization of patients.

TANGO2 Deficiency Disorder: Two Cases of Developmental Delay Preceding Metabolic Crisis.

BACKGROUND: TANGO2 deficiency disorder is a rare genetic disease caused by biallelic defects in TANGO2 gene. METHODS: We report the clinical phenotype of two children with TANGO2 deficiency disorder. RESULTS: Patient 1 is a female child presenting with developmental delay and microcephaly during the second year of life, who evolved with severe cognitive impairment, facial dysmorphisms, spastic paraparesis, and atonic seizures. At age 13 years, she was hospitalized due to an episode of rhabdomyolysis complicated with cardiac arrhythmia and hypothyroidism. Patient 2 is a female child with dysmorphic facial features, cleft palate, and developmental delay who was diagnosed with DiGeorge syndrome. At age three years, she presented with an acute episode of severe rhabdomyolysis in the context of human herpesvirus 6 infection. After the resolution of this acute episode, she maintained recurrent muscle weakness with axial hypotonia and progressive spasticity of the lower extremities. In both patients, diagnosis of TANGO2 deficiency disorder was only confirmed after an acute metabolic crisis. CONCLUSIONS: A high index of suspicion for TANGO2 deficiency disorder is needed in patients with developmental delay or other neurological symptoms and episodic rhabdomyolysis.

Salmonellosis in Children at a Portuguese Hospital: A Retrospective Study.

INTRODUCTION: Salmonellosis represents a considerable health, social and economic burden in both high- and low-income countries. Recently, in Portugal, most cases of Salmonella infections have been reported in children under 15 years of age. The main aim of this study was to characterize, from an epidemiological, microbiological, and clinical perspective, cases of Salmonella isolation among children. MATERIAL AND METHODS: The authors performed a descriptive study using retrospective analysis of cases of salmonellosis, in pediatric age, at a Portuguese Level II Hospital, between January 2015 and July 2020. RESULTS: The population included a total of 63 children, of which 81% were Portuguese. Ethnicity was identified in 13 children, most of whom were African. The median age at diagnosis was four years old (3.5 - 9 years old). Despite the small number of cases per year in our study (11), one-third were severe enough to require hospitalization. Overall, 13% of patients were treated with antibiotics. In 63% of the isolates, serotype was identified: Salmonella Enteriditis (38%), Salmonella Typhimurium (22%), and Salmonella Typhi (3%). Antibiotic resistance rates were 19% for ampicillin and 6.4% for amoxicillinclavulanic acid and cotrimoxazole. No resistance to third-generation cephalosporins was found. CONCLUSION: Given the obtained results, we intend to improve knowledge on salmonellosis in Portugal and, consequently improve prevention strategies, treatment and its notification. Although the incidence of salmonellosis has been decreasing in recent years it is the second most frequent gastrointestinal infection in the European Union, contributing to significant rates of hospitalizations and use of antibiotics in Portugal.

A noncoding single-nucleotide polymorphism at 8q24 drives IDH1-mutant glioma formation.

Establishing causal links between inherited polymorphisms and cancer risk is challenging. Here, we focus on the single-nucleotide polymorphism rs55705857, which confers a sixfold greater risk of isocitrate dehydrogenase (IDH)-mutant low-grade glioma (LGG). We reveal that rs55705857 itself is the causal variant and is associated with molecular pathways that drive LGG. Mechanistically, we show that rs55705857 resides within a brain-specific enhancer, where the risk allele disrupts OCT2/4 binding, allowing increased interaction with the Myc promoter and increased Myc expression. Mutating the orthologous mouse rs55705857 locus accelerated tumor development in an Idh1R132H-driven LGG mouse model from 472 to 172 days and increased penetrance from 30% to 75%. Our work reveals mechanisms of the heritable predisposition to lethal glioma in ~40% of LGG patients.

MPV17 Mutations Are Associated With a Quiescent Energetic Metabolic Profile.

Mutations in the MPV17 gene are associated with hepatocerebral form of mitochondrial depletion syndrome. The mechanisms through which MPV17 mutations cause respiratory chain dysfunction and mtDNA depletion is still unclear. The MPV17 gene encodes an inner membrane mitochondrial protein that was recently described to function as a non-selective channel. Although its exact function is unknown, it is thought to be important in the maintenance of mitochondrial membrane potential (ΔΨm). To obtain more information about the role of MPV17 in human disease, we investigated the effect of MPV17 knockdown and of selected known MPV17 mutations associated with MPV17 disease in vitro. We used different approaches in order to evaluate the cellular consequences of MPV17 deficiency. We found that lower levels of MPV17 were associated with impaired mitochondrial respiration and with a quiescent energetic metabolic profile. All the mutations studied destabilized the protein, resulting in reduced protein levels. We also demonstrated that different mutations caused different cellular abnormalities, including increased ROS production, decreased oxygen consumption, loss of ΔΨm, and mislocalization of MPV17 protein. Our study provides novel insight into the molecular effects of MPV17 mutations and opens novel possibilities for testing therapeutic strategies for a devastating group of disorders.

ERRγ Preserves Brown Fat Innate Thermogenic Activity.

Brown adipose tissue (BAT) adaptively transfers energy from glucose and fat into heat by inducing a gene network that uncouples mitochondrial electron transport. However, the innate transcription factors that enable the rapid adaptive response of BAT are unclear. Here, we identify estrogen-related receptor gamma (ERRγ) as a critical factor for maintaining BAT identity. ERRγ is selectively expressed in BAT versus WAT, in which, in the absence of PGC1α, it drives a signature transcriptional network of thermogenic and oxidative genes in the basal (i.e., thermoneutral) state. Mice lacking ERRγ in adipose tissue (ERRγKO mice) display marked downregulation of BAT-selective genes that leads to a pronounced whitening of BAT. Consistent with the transcriptional changes, the thermogenic capacity of ERRγKO mice is severely blunted, such that they fail to survive an acute cold challenge. These findings reveal a role for ERRγ as a critical thermoneutral maintenance factor required to prime BAT for thermogenesis.

Diplopia, Convergent Strabismus, and Eye Abduction Palsy in a 12-Year-Old Boy with Autoimmune Thyroiditis.

Pseudotumor cerebri (PTC) is defined by clinical criteria of increased intracranial pressure, elevated intracranial pressure with normal cerebrospinal fluid (CSF) composition, and exclusion of other causes such tumors, vascular abnormalities, or infections. The association of PTC with levothyroxine (LT4) has been reported. A 12-year-old boy has been followed up for autoimmune thyroiditis under LT4. Family history was irrelevant for endocrine or autoimmune diseases. A TSH level of 4.43 µUI/mL (0.39-3.10) motivated a LT4 adjustment from 75 to 88 µg/day. Five weeks later, he developed horizontal diplopia, convergent strabismus with left eye abduction palsy, and papilledema. Laboratorial evaluation revealed elevated free thyroxine level (1.05 ng/dL [0.65-1.01]) and low TSH, without other alterations. Lumbar puncture was performed and CSF opening pressure was 24 cm H2O with normal composition. Blood and CSF cultures were sterile. Brain MRI was normal. LT4 was temporarily discontinued and progressive improvement was observed, with a normal fundoscopy at day 10 and reversion of diplopia one month later. LT4 was restarted at lower dose and gradually titrated. The boy is currently asymptomatic. This case discloses the potential role of LT4 in inducing PTC. Despite its rarity and unclear association, PTC must be seen as a potential complication of LT4, after excluding all other intracranial hypertension causes.

LYRM7 mutations cause a multifocal cavitating leukoencephalopathy with distinct MRI appearance.

This study focused on the molecular characterization of patients with leukoencephalopathy associated with a specific biochemical defect of mitochondrial respiratory chain complex III, and explores the impact of a distinct magnetic resonance imaging pattern of leukoencephalopathy to detect biallelic mutations in LYRM7 in patients with biochemically unclassified leukoencephalopathy. 'Targeted resequencing' of a custom panel including genes coding for mitochondrial proteins was performed in patients with complex III deficiency without a molecular genetic diagnosis. Based on brain magnetic resonance imaging findings in these patients, we selected additional patients from a database of unclassified leukoencephalopathies who were scanned for mutations in LYRM7 by Sanger sequencing. Targeted sequencing revealed homozygous mutations in LYRM7, encoding mitochondrial LYR motif-containing protein 7, in four patients from three unrelated families who had a leukoencephalopathy and complex III deficiency. Two subjects harboured previously unreported variants predicted to be damaging, while two siblings carried an already reported pathogenic homozygous missense change. Sanger sequencing performed in the second cohort of patients revealed LYRM7 mutations in three additional patients, who were selected on the basis of the magnetic resonance imaging pattern. All patients had a consistent magnetic resonance imaging pattern of progressive signal abnormalities with multifocal small cavitations in the periventricular and deep cerebral white matter. Early motor development was delayed in half of the patients. All patients but one presented with subacute neurological deterioration in infancy or childhood, preceded by a febrile infection, and most patients had repeated episodes of subacute encephalopathy with motor regression, irritability and stupor or coma resulting in major handicap or death. LYRM7 protein was strongly reduced in available samples from patients; decreased complex III holocomplex was observed in fibroblasts from a patient carrying a splice site variant; functional studies in yeast confirmed the pathogenicity of two novel mutations. Mutations in LYRM7 were previously found in a single patient with a severe form of infantile onset encephalopathy. We provide new molecular, clinical, and neuroimaging data allowing us to characterize more accurately the molecular spectrum of LYRM7 mutations highlighting that a distinct and recognizable magnetic resonance imaging pattern is related to mutations in this gene. Inter- and intrafamilial variability exists and we observed one patient who was asymptomatic by the age of 6 years.

A novel postoperative immobilization model for murine Achilles tendon sutures.

The body's motion and function are all in part effected by a vital tissue, the tendon. Tendon injury often results in limited functioning after postoperative procedures and even for a long time after rehabilitation. Although numerous studies have reported surgical procedures using animal models which have contributed to both basic and clinical research, modeling of tendon sutures or postoperative immobilizations has not been performed on small experimental animals, such as mice. In this study we have developed an easy Achilles tendon suture and postoperative ankle fixation model in a mouse. Right Achilles tendons were incised and 10-0 nylons were passed through the proximal and distal ends using a modified Kessler method. Subsequently, the right ankle was immobilized in a plantarflexed position with novel splints, which were made from readily available extension tubes. Restriction of the tendon using handmade splints reduced swelling, as opposed to fixating with the usual plaster of Paris. Using this method, the usage of the right Achilles tendons began on postoperative days 13.5 ± 4.6, which indicated healing within two weeks. Therefore our simple short-term murine Achilles tendon suture procedure is useful for studying immediate tendon repair mechanisms in various models, including genetically-modified mice.

ERRs Mediate a Metabolic Switch Required for Somatic Cell Reprogramming to Pluripotency.

Cell metabolism is adaptive to extrinsic demands; however, the intrinsic metabolic demands that drive the induced pluripotent stem cell (iPSC) program remain unclear. Although glycolysis increases throughout the reprogramming process, we show that the estrogen-related nuclear receptors (ERRα and ERRγ) and their partnered co-factors PGC-1α and PGC-1ß are transiently induced at an early stage, resulting in a burst of oxidative phosphorylation (OXPHOS) activity. Upregulation of ERRα or ERRγ is required for the OXPHOS burst in both human and mouse cells, respectively, as well as iPSC generation itself. Failure to induce this metabolic switch collapses the reprogramming process. Furthermore, we identify a rare pool of Sca1(-)/CD34(-) sortable cells that is highly enriched in bona fide reprogramming progenitors. Transcriptional profiling confirmed that these progenitors are ERRγ and PGC-1ß positive and have undergone extensive metabolic reprogramming. These studies characterize a previously unrecognized, ERR-dependent metabolic gate prior to establishment of induced pluripotency.

Intestinal FXR agonism promotes adipose tissue browning and reduces obesity and insulin resistance.

The systemic expression of the bile acid (BA) sensor farnesoid X receptor (FXR) has led to promising new therapies targeting cholesterol metabolism, triglyceride production, hepatic steatosis and biliary cholestasis. In contrast to systemic therapy, bile acid release during a meal selectively activates intestinal FXR. By mimicking this tissue-selective effect, the gut-restricted FXR agonist fexaramine (Fex) robustly induces enteric fibroblast growth factor 15 (FGF15), leading to alterations in BA composition, but does so without activating FXR target genes in the liver. However, unlike systemic agonism, we find that Fex reduces diet-induced weight gain, body-wide inflammation and hepatic glucose production, while enhancing thermogenesis and browning of white adipose tissue (WAT). These pronounced metabolic improvements suggest tissue-restricted FXR activation as a new approach in the treatment of obesity and metabolic syndrome.

Methylome, transcriptome, and PPAR(γ) cistrome analyses reveal two epigenetic transitions in fat cells.

Although DNA modification is adaptive to extrinsic demands, little is known about epigenetic alterations associated with adipose differentiation and reprogramming. We systematically characterized the global trends of our methylome and transcriptome data with reported PPAR(γ) cistrome data. Our analysis revealed that DNA methylation was altered between induced pluripotent stem cells (iPSCs) and adipose derived stem cells (ADSCs). Surprisingly, DNA methylation was not obviously changed in differentiation from ADSCs to mature fat cells (FatCs). This indicates that epigenetic predetermination of the adipogenic fate is almost established prior to substantial expression of the lineage. Furthermore, the majority of the PPAR(γ) cistrome corresponded to the pre-set methylation profile between ADSCs and FatCs. In contrast to the pre-set model, we found that a subset of PPAR(γ)-binding sites for late-expressing genes such as Adiponectin and Adiponectin receptor2 were differentially methylated independently of the early program. Thus, these analyses identify two types of epigenetic mechanisms that distinguish the pre-set cell fate and later stages of adipose differentiation.

Atypical phenotype in two patients with LAMA2 mutations.

Congenital muscular dystrophy type 1A is caused by mutations in the LAMA2 gene, which encodes the α2-chain of laminin. We report two patients with partial laminin-α2 deficiency and atypical phenotypes, one with almost exclusive central nervous system involvement (cognitive impairment and refractory epilepsy) and the second with marked cardiac dysfunction, rigid spine syndrome and limb-girdle weakness. Patients underwent clinical, histopathological, imaging and genetic studies. Both cases have two heterozygous LAMA2 variants sharing a potentially pathogenic missense mutation c.2461A>C (p.Thr821Pro) located in exon 18. Brain MRI was instrumental for the diagnosis, since muscular examination and motor achievements were normal in the first patient and there was a severe cardiac involvement in the second. The clinical phenotype of the patients is markedly different which could in part be explained by the different combination of mutations types (two missense versus a missense and a truncating mutation).

Ophthalmoplegic migraine and infundibular dilatation of a cerebral artery.

Ophthalmoplegic migraine (OM) is a childhood disorder of uncertain etiology manifesting recurrent unilateral headache associated with a transitory oculomotor (usually IIIrd nerve) palsy. Recent publications emphasize the finding on MRI of contrast enhancement in the IIIrd nerve suggesting that OM may be a recurrent inflammatory neuropathy. We report the case of a 7-year-old boy with typical symptoms of this disorder. Angio MR and Angio CT revealed the presence of an infundibular dilatation of a perforating branch of the posterior cerebral artery adjacent to the symptomatic IIIrd nerve. We speculate that this and perhaps other cases of OM may have a different pathophysiology related to compression of the IIIrd nerve by an adjacent vascular structure that could activate the trigeminovascular system and produce migrainous pain.