Local retinoic acid signaling directs emergence of the extraocular muscle functional unit.

Coordinated development of muscles, tendons, and their attachment sites ensures emergence of functional musculoskeletal units that are adapted to diverse anatomical demands among different species. How these different tissues are patterned and functionally assembled during embryogenesis is poorly understood. Here, we investigated the morphogenesis of extraocular muscles (EOMs), an evolutionary conserved cranial muscle group that is crucial for the coordinated movement of the eyeballs and for visual acuity. By means of lineage analysis, we redefined the cellular origins of periocular connective tissues interacting with the EOMs, which do not arise exclusively from neural crest mesenchyme as previously thought. Using 3D imaging approaches, we established an integrative blueprint for the EOM functional unit. By doing so, we identified a developmental time window in which individual EOMs emerge from a unique muscle anlage and establish insertions in the sclera, which sets these muscles apart from classical muscle-to-bone type of insertions. Further, we demonstrate that the eyeballs are a source of diffusible all-trans retinoic acid (ATRA) that allow their targeting by the EOMs in a temporal and dose-dependent manner. Using genetically modified mice and inhibitor treatments, we find that endogenous local variations in the concentration of retinoids contribute to the establishment of tendon condensations and attachment sites that precede the initiation of muscle patterning. Collectively, our results highlight how global and site-specific programs are deployed for the assembly of muscle functional units with precise definition of muscle shapes and topographical wiring of their tendon attachments.

DNAJC30 defect: a frequent cause of recessive Leber hereditary optic neuropathy and Leigh syndrome.

The recent description of biallelic DNAJC30 variants in Leber hereditary optic neuropathy (LHON) and Leigh syndrome challenged the longstanding assumption for LHON to be exclusively maternally inherited and broadened the genetic spectrum of Leigh syndrome, the most frequent paediatric mitochondrial disease. Herein, we characterize 28 so far unreported individuals from 26 families carrying a homozygous DNAJC30 p.Tyr51Cys founder variant, 24 manifesting with LHON, two manifesting with Leigh syndrome, and two remaining asymptomatic. This collection of unreported variant carriers confirms sex-dependent incomplete penetrance of the homozygous variant given a significant male predominance of disease and the report of asymptomatic homozygous variant carriers. The autosomal recessive LHON patients demonstrate an earlier age of disease onset and a higher rate of idebenone-treated and spontaneous recovery of vision in comparison to reported figures for maternally inherited disease. Moreover, the report of two additional patients with childhood- or adult-onset Leigh syndrome further evidences the association of DNAJC30 with Leigh syndrome, previously only reported in a single childhood-onset case.

Subjective and polysomnographic evaluation of sleep in mitochondrial optic neuropathies.

Leber hereditary optic neuropathy and Dominant optic atrophy are associated with a selective loss of retinal ganglion cells (RGC). A subtype of RGC is responsible for light-dependent physiological processes. The aim of our study was to evaluate both subjective and objective sleep parameters in 36 (18 males; mean age 33.8 ± 16.7) symptomatic/asymptomatic subjects with Leber hereditary optic neuropathy and dominant optic atrophy. The Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale (ESS) and nocturnal polysomnography were used to assess sleep disturbances and sleep quality. The questionnaires indicated significantly worse sleep quality (PSQI > 5; average 7.7 ± 3.8) in 21 (70%) and excessive daytime sleepiness (ESS > 10; average 6.3 ± 5.8) in six (20%) individuals. Nocturnal polysomnography has not revealed any significant changes of sleep structure. Rapid eye movement (REM) sleep without atonia was observed in two patients with Leber hereditary optic neuropathy. Obstructive sleep apnea was noted in eight cases. No correlation between subjective and polysomnographic data and no differences between symptomatic and asymptomatic groups were observed. None of the subjects fulfilled criteria for a circadian sleep disorder. In both symptomatic and asymptomatic individuals, a subjective decrease of the quality of sleep and wakefulness was noted without any correlation on polysomnography.

Knock-Out of ACBD3 Leads to Dispersed Golgi Structure, but Unaffected Mitochondrial Functions in HEK293 and HeLa Cells.

The Acyl-CoA-binding domain-containing protein (ACBD3) plays multiple roles across the cell. Although generally associated with the Golgi apparatus, it operates also in mitochondria. In steroidogenic cells, ACBD3 is an important part of a multiprotein complex transporting cholesterol into mitochondria. Balance in mitochondrial cholesterol is essential for proper mitochondrial protein biosynthesis, among others. We generated ACBD3 knock-out (ACBD3-KO) HEK293 and HeLa cells and characterized the impact of protein absence on mitochondria, Golgi, and lipid profile. In ACBD3-KO cells, cholesterol level and mitochondrial structure and functions are not altered, demonstrating that an alternative pathway of cholesterol transport into mitochondria exists. However, ACBD3-KO cells exhibit enlarged Golgi area with absence of stacks and ribbon-like formation, confirming the importance of ACBD3 in Golgi stacking. The glycosylation of the LAMP2 glycoprotein was not affected by the altered Golgi structure. Moreover, decreased sphingomyelins together with normal ceramides and sphingomyelin synthase activity reveal the importance of ACBD3 in ceramide transport from ER to Golgi.

Severe phenotype of ATP6AP1-CDG in two siblings with a novel mutation leading to a differential tissue-specific ATP6AP1 protein pattern, cellular oxidative stress and hepatic copper accumulation.

Congenital disorders of glycosylation (CDG) represent a wide range of >140 inherited metabolic diseases, continually expanding not only with regards to the number of newly identified causative genes, but also the heterogeneity of the clinical and molecular presentations within each subtype. The deficiency of ATP6AP1, an accessory subunit of the vacuolar H+ -ATPase, is a recently characterised N- and O-glycosylation defect manifesting with immunodeficiency, hepatopathy and cognitive impairment. At the cellular level, the latest studies demonstrate a complex disturbance of metabolomics involving peroxisomal function and lipid homeostasis in the patients. Our study delineates a case of two severely affected siblings with a new hemizygous variant c.221T>C (p.L74P) in ATP6AP1 gene, who both died due to liver failure before reaching 1 year of age. We bring novel pathobiochemical observations including the finding of increased reactive oxygen species in the cultured fibroblasts from the older boy, a striking copper accumulation in his liver, as well as describe the impact of the mutation on the protein in different organs, showing a tissue-specific pattern of ATP6AP1 level and its posttranslational modification.

Multisystem mitochondrial diseases due to mutations in mtDNA-encoded subunits of complex I.

BACKGROUND: Maternally inherited complex I deficiencies due to mutations in MT-ND genes represent a heterogeneous group of multisystem mitochondrial disorders (MD) with a unfavourable prognosis. The aim of the study was to characterize the impact of the mutations in MT-ND genes, including the novel m.13091 T > C variant, on the course of the disease, and to analyse the activities of respiratory chain complexes, the amount of protein subunits, and the mitochondrial energy-generating system (MEGS) in available muscle biopsies and cultivated fibroblasts. METHODS: The respiratory chain complex activities were measured by spectrophotometry, MEGS were analysed using radiolabelled substrates, and protein amount by SDS-PAGE or BN-PAGE in muscle or fibroblasts. RESULTS: In our cohort of 106 unrelated families carrying different mtDNA mutations, we found heteroplasmic mutations in the genes MT-ND1, MT-ND3, and MT-ND5, including the novel variant m.13091 T > C, in 13 patients with MD from 12 families. First symptoms developed between early childhood and adolescence and progressed to multisystem disease with a phenotype of Leigh or MELAS syndromes. MRI revealed bilateral symmetrical involvement of deep grey matter typical of Leigh syndrome in 6 children, cortical/white matter stroke-like lesions suggesting MELAS syndrome in 3 patients, and a combination of cortico-subcortical lesions and grey matter involvement in 4 patients. MEGS indicated mitochondrial disturbances in all available muscle samples, as well as a significantly decreased oxidation of [1-14C] pyruvate in fibroblasts. Spectrophotometric analyses revealed a low activity of complex I and/or complex I + III in all muscle samples except one, but the activities in fibroblasts were mostly normal. No correlation was found between complex I activities and mtDNA mutation load, but higher levels of heteroplasmy were generally found in more severely affected patients. CONCLUSIONS: Maternally inherited complex I deficiencies were found in 11% of families with mitochondrial diseases in our region. Six patients manifested with Leigh, three with MELAS. The remaining four patients presented with an overlap between these two syndromes. MEGS, especially the oxidation of [1-14C] pyruvate in fibroblasts might serve as a sensitive indicator of functional impairment due to MT-ND mutations. Early onset of the disease and higher level of mtDNA heteroplasmy were associated with a worse prognosis.

Sideroblastic anemia associated with multisystem mitochondrial disorders.

BACKGROUND: Sideroblastic anemia represents a heterogeneous group of inherited or acquired diseases with disrupted erythroblast iron utilization, ineffective erythropoiesis, and variable systemic iron overload. In a cohort of 421 patients with multisystem mitochondrial diseases, refractory anemia was found in 8 children. RESULTS: Five children had sideroblastic anemia with increased numbers of ring sideroblasts >15%. Two of the children had a fatal course of MLASA1 syndrome (mitochondrial myopathy, lactic acidosis, and sideroblastic anemia [SA]) due to a homozygous, 6-kb deletion in the PUS1 gene, part of the six-member family of pseudouridine synthases (pseudouridylases). Large homozygous deletions represent a novel cause of presumed PUS1-loss-of-function phenotype. The other three children with SA had Pearson syndrome (PS) due to mtDNA deletions of 4 to 8 kb; two of these children showed early onset of PS and died due to repeated sepsis; the other child had later onset of PS and survived as the hematological parameters normalized and the disease transitioned to Kearns-Sayre syndrome. In addition, anemia without ring sideroblasts was found in three other patients with mitochondrial disorders, including two children with later onset of PS and one child with failure to thrive, microcephaly, developmental delay, hypertrophic cardiomyopathy, and renal tubular acidosis due to the heterozygous mutations c.610A>G (p.Asn204Asp) and c.674C>T (p.Pro225Leu) in the COX10 gene encoding the cytochrome c oxidase assembly factor. CONCLUSIONS: Sideroblastic anemia was found in fewer than 1.2% of patients with multisystem mitochondrial disease, and it was usually associated with an unfavorable prognosis.

Attenuated Type of Asphyxiating Thoracic Dysplasia due to Mutations in DYNC2H1 Gene.

Asphyxiating thoracic dysplasia (ATD) represents a heterogeneous group of skeletal dysplasias with short ribs, narrow chest and reduced thoracic capacity. Mutations in several genes including IFT80, DYNC2H1, TTC21B and WDR19 have been found in patients with ATD. Both severe and milder course of the disease were described in correlation with secondary involvement of lung's function. Two children with attenuated form of ATD are described. Their anthropometric parameters for birth weight, length and head circumference were normal but narrow thorax was observed in both of them in early infancy with chest circumference < -3 SD (standard deviation) in comparison to age related controls. The postnatal adaptation and development of both children was uneventful except for mild tachypnoea in one of them which persisted till the age of 6 months. In both children, radiographs revealed narrow upper half of the chest with shorter ribs and atypical configuration of pelvis with horizontally running acetabula and coarse internal edges typical for ATD. Molecular analyses using whole exome sequencing in one family revealed that the patient is compound heterozygote in DYNC2H1 gene for a frame-shift mutation c.4458delT resulting in premature stop-codon p.Phe1486Leufs*11 and a missense mutation c.9044A>G (p.Asp3015Gly). The second family refused the DNA analysis. Regular monitoring of anthropometric parameters during childhood is of big importance both in health and disease. In addition, measurement of the chest circumference should be included, at least at birth and during infancy.

POLR3B-associated leukodystrophy: clinical, neuroimaging and molecular-genetic analyses in four patients: clinical heterogeneity and novel mutations in POLR3B gene.

INTRODUCTION AND AIM OF THE STUDY: White matter disorders represent a spectrum of neurological diseases frequently associated with an unfavourable prognosis and a delay in diagnostics. We report the broad phenotypic spectrum of a rare hypomyelinating leukodystrophy and three novel mutations. Further, we aim to explore the role of the combined clinical and neuroimaging diagnostic approach in the era of whole exome sequencing. MATERIALS AND METHODS: We present a clinical, neuroimaging and molecular-genetic characterisation of four patients from three families suffering from a rare genetic leukoencephalopathy. Two severely affected siblings (P1, P2) manifested a profound developmental delay, cerebellar symptomatology, microcephaly, failure to thrive, short stature and delayed teeth eruption with oligodontia. The other two patients (P3, P4), on the contrary, suffer from substantially less serious impairment with mild to moderate developmental delay and cerebellar symptomatology, delayed teeth eruption, or well-manageable epilepsy. In all four patients, magnetic resonance revealed cerebellar atrophy and supratentorial hypomyelination with T2-weight hypointensities in the areas of the ventrolateral thalamic nuclei, corticospinal tract and the dentate nuclei. RESULTS: Using whole-exome sequencing in P1, P2 and P3, and targeted sequencing in P4, pathogenic variants were disclosed in POLR3B, a gene encoding one of 17 subunits of DNA-dependent RNA polymerase III - all patients were compound heterozygotes for point mutations. Three novel mutations c.727A>G (p.Met243Val) and c.2669G>A (p.Arg890His) (P1, P2), and c.1495G>A (p.Met499Val) (P3) were found. Magnetic resonance revealed the characteristic radiological pattern of POLR3-leukodystrophies in our patients. CONCLUSION AND CLINICAL IMPLICATIONS: The diagnosis of POLR3-associated leukodystrophies can be significantly accelerated using the combined clinical and neuroradiological recognition pattern. Therefore, it is of crucial importance to raise the awareness of this rare disorder among clinicians. Molecular-genetic analyses are indispensable for a swift diagnosis confirmation in cases of clear clinical suspicion, and for diagnostic search in patients with less pronounced symptomatology. They represent an invaluable tool for unravelling the complex genetic background of heritable white matter disorders.

Revisiting mitochondrial diagnostic criteria in the new era of genomics.

PurposeDiagnosing primary mitochondrial diseases (MDs) is challenging in clinical practice. The mitochondrial disease criteria (MDC) have been developed to quantify the clinical picture and evaluate the probability of an underlying MD and the need for a muscle biopsy. In this new genetic era with next-generation sequencing in routine practice, we aim to validate the diagnostic value of MDC.MethodsWe retrospectively studied MDC in a multicenter cohort of genetically confirmed primary MD patients.ResultsWe studied 136 patients (61 male, 91 nuclear DNA (nDNA) mutations). Forty-five patients (33%) had probable MD and 69 (51%) had definite MD according to the MDC. A muscle biopsy was performed in 63 patients (47%). Patients with nDNA mutations versus mitochondrial DNA mutations were younger (6.4 ± 9.7 versus 19.5 ± 17.3 y) and had higher MDC (7.07 ± 1.12/8 versus 5.69 ± 1.94/8). At a cutoff of 6.5/8, the sensitivity to diagnose patients with nDNA mutations is 72.5% with a positive predictive value of 69.5%. In the nDNA mutation group, whole-exome sequencing could diagnose patients with lower scores (MDC (6.84 ± 1.51/8) compared to Sanger sequencing MDC (7.44 ± 1.13/8, P = 0.025)). Moreover 7/8 patients diagnosed with possible MD by MDC were diagnosed by whole-exome sequencing.ConclusionMDC remain very useful in the clinical diagnosis of MD, in interpreting whole-exome results and deciding on the need for performing muscle biopsy.

Periodic fevers and other autoinflammatory diseases.

Autoinflammatory diseases represent a relatively new and rapidly evolving group of rare disorders associated with mutations of genes encoding proteins with a key regulatory role in inflammatory response. Gradual discovery of mechanisms that link genetic disorder with its biochemical and immunological consequences leading to continuous or episodic inflammatory stimulation has enabled introduction of directed immunotherapies. Periodic fever syndromes belong to the so far best-known entities: familial Mediterranean fever, mevalonate kinase deficiency, cryopyrinopathies and TNF-receptor associated periodic syndrome. These inherited disorders usually manifest in childhood with variably long febrile episodes accompanied with the spectrum of other skin and organ inflammatory features and elevation of laboratory markers of inflammation. Uncontrolled disease may lead to secondary amyloidosis. Directed anti-inflammatory therapy can prevent evolution of organ damage. In children benign syndrome of periodic fever with aphtae, pharyngitis and cervical adenitis is the most common self-limited disorder without clear genetic disposition. Following other autoinflammatory disease groups are described - pyogenic syndromes, disorders with skin and bone manifestations, granulomatous diseases, monogenic vasculopathies and diseases associated with proteasome disorder. Diagnosis of autoinflammatory diseases is often delayed due to their extreme rarity. Increasing efficacy and availability of molecular-genetic testing and centralization of diagnostics and clinical care in a specialized center for children as well as adults can in the future improve quality of care for patients with these rare conditions. Keywords: autoinflammatory diseases (AID), periodic fever syndromes, FMF, CAPS, MKD, TRAPS, PFAPA, NGS.

Thymidine kinase 2 and alanyl-tRNA synthetase 2 deficiencies cause lethal mitochondrial cardiomyopathy: case reports and review of the literature.

Cardiomyopathy is a common manifestation in neonates and infants with mitochondrial disorders. In this study, we report two cases manifesting with fatal mitochondrial hypertrophic cardiomyopathy, which include the third known patient with thymidine kinase 2 deficiency and the ninth patient with alanyl-tRNA synthetase 2 deficiency. The girl with thymidine kinase 2 deficiency had hypertrophic cardiomyopathy together with regression of gross motor development at the age of 13 months. Neurological symptoms and cardiac involvement progressed into severe myopathy, psychomotor arrest, and cardiorespiratory failure at the age of 22 months. The imaging methods and autoptic studies proved that she suffered from unique findings of leucoencephalopathy, severe, mainly cerebellar neuronal degeneration, and hepatic steatosis. The girl with alanyl-tRNA synthetase 2 deficiency presented with cardiac failure and underlying hypertrophic cardiomyopathy within 12 hours of life and subsequently died at 9 weeks of age. Muscle biopsy analyses demonstrated respiratory chain complex I and IV deficiencies, and histological evaluation revealed massive mitochondrial accumulation and cytochrome c oxidase-negative fibres in both cases. Exome sequencing in the first case revealed compound heterozygozity for one novel c.209T>C and one previously published c.416C>T mutation in the TK2 gene, whereas in the second case homozygozity for the previously described mutation c.1774C>T in the AARS2 gene was determined. The thymidine kinase 2 mutations resulted in severe mitochondrial DNA depletion (to 12% of controls) in the muscle. We present, for the first time, severe leucoencephalopathy and hepatic steatosis in a patient with thymidine kinase 2 deficiency and the finding of a ragged red fibre-like image in the muscle biopsy in a patient with alanyl-tRNA synthetase 2 deficiency.

Hereditary Multiple Exostoses: Clinical, Molecular and Radiologic Survey in 9 Families.

Hereditary multiple exostoses (HME) represents a heterogeneous group of diseases often associated with progressive skeletal deformities. Most frequently, mutations in EXT1 and EXT2 genes with autosomal dominant inheritance are responsible for HME. In our group of 9 families with HME we evaluated the clinical course of the disease and analysed molecular background using Sanger sequencing and MLPA in EXT1 and EXT2 genes. The mean age in our group of patients, when the first exostosis was recognised was 4.5 years (range 2-10 years) and the number of exostoses per one patient documented on X-ray ranged from 2 to 54. Most of the exostoses developed before the growth was completed and they were dominantly localised in the distal femurs, proximal tibia, proximal humerus and distal radius. In all patients, at least one to 8 surgeries were necessary due to complaints and local complications, but neither patient developed malignant transformation. In half of the patients, the disease resulted in short stature. DNA analyses were positive in 7 families. In five probands, different EXT1 gene mutations resulting in premature stop-codon (p.Gly124Argfs*65, p.Leu191*, p.Trp364Lysfs*11, p.Val371Glyfs*10, p.Leu490Profs*31) were found. In two probands, nonsense mutations were found in EXT2 gene (p.Val187Profs*115, p.Cys319fs*46). Five mutations have been novel and two mutations have occurred de novo in probands. Although the risk for malignant transformation is usually low, especially in patients with low number of exostoses, early diagnostics and longitudinal follow up of patients is of a big importance, because early surgery can prevent progression of secondary bone deformities.

Neuroinflammation, mitochondrial defects and neurodegeneration in mucopolysaccharidosis III type C mouse model.

Severe progressive neurological paediatric disease mucopolysaccharidosis III type C is caused by mutations in the HGSNAT gene leading to deficiency of acetyl-CoA: α-glucosaminide N-acetyltransferase involved in the lysosomal catabolism of heparan sulphate. To understand the pathophysiology of the disease we generated a mouse model of mucopolysaccharidosis III type C by germline inactivation of the Hgsnat gene. At 6-8 months mice showed hyperactivity, and reduced anxiety. Cognitive memory decline was detected at 10 months and at 12-13 months mice showed signs of unbalanced hesitant walk and urinary retention. Lysosomal accumulation of heparan sulphate was observed in hepatocytes, splenic sinus endothelium, cerebral microglia, liver Kupffer cells, fibroblasts and pericytes. Starting from 5 months, brain neurons showed enlarged, structurally abnormal mitochondria, impaired mitochondrial energy metabolism, and storage of densely packed autofluorescent material, gangliosides, lysozyme, phosphorylated tau, and amyloid-ß. Taken together, our data demonstrate for the first time that deficiency of acetyl-CoA: α-glucosaminide N-acetyltransferase causes lysosomal accumulation of heparan sulphate in microglial cells followed by their activation and cytokine release. They also show mitochondrial dysfunction in the neurons and neuronal loss explaining why mucopolysaccharidosis III type C manifests primarily as a neurodegenerative disease.

Two novel mutations in seven Czech and Slovak kindreds with familial neurohypophyseal diabetes insipidus-benefit of genetic testing.

UNLABELLED: Familial neurohypophyseal diabetes insipidus (FNDI) is a rare hereditary disorder with unknown prevalence characterized by arginine-vasopressin hormone (AVP) deficiency resulting in polyuria and polydipsia from early childhood. We report the clinical manifestation and genetic test results in seven unrelated kindreds of Czech or Slovak origin with FNDI phenotype. The age of the sign outset ranged from 2 to 17 years with remarkable interfamilial and intrafamilial variability. Inconclusive result of the fluid deprivation test in three children aged 7 and 17 years old might cause misdiagnosis; however, the AVP gene analysis confirmed the FNDI. The seven families segregated together five different mutations, two of them were novel (c.164C > A, c.298G > C). In addition, DNA analysis proved mutation carrier status in one asymptomatic 1-year-old infant. CONCLUSIONS: The present study together with previously published data identified 38 individuals with FNDI in the studied population of 16 million which predicts a disease prevalence of 1:450,000 for the Central European region. The paper underscores that diagnostic water deprivation test may be inconclusive in polyuric children with partial diabetes insipidus and points to the clinical importance and feasibility of molecular genetic testing for AVP gene mutations in the proband and her/his first degree relatives. WHAT IS KNOWN: • At least 70 different mutations were reported to date in about 100 families with neurohypophyseal diabetes insipidus (FNDI), and new mutations appear sporadically. What is New: • Two novel mutations of the AVP gene are reported • The importance of molecular testing in children with polyuria and inconclusive water deprivation test is emphasized.

TMEM70 deficiency: long-term outcome of 48 patients.

OBJECTIVES: TMEM70 deficiency is the most common nuclear-encoded defect affecting the ATP synthase. In this multicentre retrospective study we characterise the natural history of the disease, treatment and outcome in 48 patients with mutations in TMEM70. Eleven centers from eight European countries, Turkey and Israel participated. RESULTS: All 27 Roma and eight non-Roma patients were homozygous for the common mutation c.317-2A > G. Five patients were compound heterozygotes for the common mutation and mutations c.470 T > A, c.628A > C, c.118_119insGT or c.251delC. Six Arab Muslims and two Turkish patients were homozygous for mutations c.238C > T, c.316 + 1G > T, c.336 T > A, c.578_579delCA, c.535C > T, c.359delC. Age of onset was neonatal in 41 patients, infantile in six cases and two years in one child. The most frequent symptoms at onset were poor feeding, hypotonia, lethargy, respiratory and heart failure, accompanied by lactic acidosis, 3-methylglutaconic aciduria and hyperammonaemia. Symptoms further included: developmental delay (98%), hypotonia (95%), faltering growth (94%), short stature (89%), non-progressive cardiomyopathy (89%), microcephaly (71%), facial dysmorphism (66%), hypospadias (50% of the males), persistent pulmonary hypertension of the newborn (22%) and Wolff-Parkinson-White syndrome (13%). One or more acute metabolic crises occurred in 24 surviving children, frequently followed by developmental regression. Hyperammonaemic episodes responded well to infusion with glucose and lipid emulsion, and ammonia scavengers or haemodiafiltration. Ten-year survival was 63%, importantly for prognostication, no child died after the age of five years. CONCLUSION: TMEM70 deficiency is a panethnic, multisystemic disease with variable outcome depending mainly on adequate management of hyperammonaemic crises in the neonatal period and early childhood.

Glycogen storage disease-like phenotype with central nervous system involvement in a PGM1-CDG patient.

OBJECTIVES: A 10-year-old boy presented with cleft palate, hepatopathy, cholecystolithiasis, myopathy, coagulopathy, hyperlipidemia, hypoglycemia, hyperuricemia, short stature, obesity, hypothyroidism, microcephaly and mild intellectual disability. The multi-systemic manifestation involving certain distinct clinical features prompted us to search for a subtype of congenital disorders of glycosylation (CDG). METHODS: The patient was screened for CDG by examining the distribution of transferrin (TRF) and apolipoprotein C-III (ApoC-III) sialylated isoforms using isoelectric focusing of serum. This was followed by spectrophotometric measurement of phosphoglucomutase 1 (PGM1) activity in fibroblasts and molecular analysis including sequencing and PCR-RFLP of PGM1 gene. Selected bioinformatics tools were used to evaluate the data. RESULTS: Increased relative levels of di-, mono- and asialotransferrin reflected a defect of N-glycosylation in the patient. Markedly decreased activity of PGM1 corresponding to less than 5% of control´s was found. Sequencing of PGM1 gene revealed the presence of two heterozygous missense mutations c.1010C>T (p.T337M) and c.1508G>A (p.R503Q), whose pathogenicity was confirmed by in silico analysis. CONCLUSION: We report the first Czech patient with a glycosylation disorder due to PGM1 deficiency. Compared to the described cases, no dilated cardiomyopathy was noted in our patient. However, he suffered from a mild neurological impairment, which is an uncommon feature that extends the phenotype associated with PGM1-CDG. Lactose-rich diet, which was previously reported to have ameliorated the clinical symptoms in some PGM1-CDG patients, did not result in any improvement in our patient.

[Psychiatric disturbances in five patients with MELAS syndrome]. / Zaburzenia psychiczne u pieciu pacjentów cierpiacych na zespól MELAS.

OBJECTIVES: Mitochondrial disorders of energetic metabolism (MD) represent a heterogeneous group of diseases manifesting at any age with a broad spectrum of clinical symptoms, including psychiatric disorders. METHODS: The aim of the study was to characterize psychiatric symptoms and diagnoses in five patients with MELAS syndrome between the ages of 17 and 53 years. RESULTS: Four of MELAS patients them harbored the prevalent mitochondrial DNA (mtDNA) mutation 3243A>G, and one patient had the mtDNA mutation 12706T>C. Three patients had positive family histories for MELAS syndrome. In one patient, depression was diagnosedas the first symptom ofMELAS syndrome. Depression also preceded a stroke-like episode in one patient. Four patients had disturbed cognitive functions, confusional states occurred in three patients. One patient manifested psychotic (schizophrenia-like) symptoms. CONCLUSION: Mitochondrial disorders deserve consideration as part of the differential diagnosis, especially, if there is suspected involvement of other organ groups or positive family history of MD.

Different laboratory and muscle biopsy findings in a family with an m.8851T>C mutation in the mitochondrial MTATP6 gene.

We report the second known family with a very rare, maternally inherited missense m.8851T>C mutation in the mitochondrial MTATP6 gene. A failure to thrive, microcephaly, psychomotor retardation and hypotonia were present in a 3-year-old girl with a high mtDNA mutation load (87-97%). Ataxia and Leigh syndrome were subsequently documented in a neurological examination and brain MRI. A muscle biopsy demonstrated decreased ATP synthase and an accumulation of succinate dehydrogenase products, indicating mitochondrial myopathy. Her 36-year-old mother (68% blood heteroplasmy) developed peripheral neuropathy and muscle weakness at the age of 22 years. Our findings extend the clinical and laboratory phenotype associated with the m.8851T>C mutation.