Hypotrichosis with cone-rod dystrophy in a patient with cadherin 3 (CDH3) mutation.

PURPOSE: To investigate a very rare case of hypotrichosis with cone-rod dystrophy caused by a P-cadherin CDH3 mutation. METHODS: A 16-year-old Syrian girl was examined at age 9 and 14 years with an ophthalmological examination, fundus imaging, OCT and electrophysiological recordings (ERG and PERG). A disease-targeted gene panel sequencing was performed. RESULTS: Fundus images showed pigmentations at the posterior eye pole to the mid periphery, as well as vessel tortuosity. OCT images revealed a loss of the outer retinal segments and IS/OS in the central macula. The scotopic and photopic ERGs showed moderately reduced amplitudes at age 9 years that became severely reduced at age of 14 years. The PERG was undetectable at age 9 years. In color vision testing, protan-deutan confusion errors occurred. Gene panel analysis revealed one homozygous mutation in CDH3 (c.1508G>A; p.Arg503His). CONCLUSION: This case shows that a CDH3 mutation besides macula dystrophy can cause widespread cone-rod dystrophy with hypotrichosis without any other pathology besides hypoplastic nails. This points to a common pathway of hair growth and photoreceptor development that can be disturbed by a CDH3 mutation (c.1508G>A; p.Arg503His) located in the EC4 repeat region of the gene.

Why is it necessary to examine retina when the patient suffers from aplastic anemia?

PURPOSES: To inform about a case of Revesz syndrome (RS) with initial ophthalmological symptomatology of severe proliferative vitreoretinopathy of the left eye (LE). After the aplastic anemia had developed, RS was established. The exudative retinopathy was successfully treated with photocoagulation on the right eye (RE). BACKGROUND: RS is characterized by fatal bone marrow failure, exudative retinopathy, neuroradiographic abnormalities, neurodevelopmental delay and skin abnormalities. Non-treated exudative retinopathy leads to blindness. METHODS: We report ophthalmological findings as follows: fundus photography and fluorescein angiography (FA) acquired by examinations under general anesthesia in patient with RS. Results of genetic tests helped to establish the diagnosis. RESULTS: Two­year old Caucasian male was examined due to total retinal detachment on LE and signs of chorioretinal scarring on RE. In preoperative screening, thrombocytopenia was detected; later, severe pancytopenia developed. Considering the hematological findings and clinical appearance, we suspected RS, which was confirmed by genetic tests. We found a pathogenic mutation in gene TINF2 (variant c.865C>T;p.Pro289Ser) in a mosaic state with autosomal dominant mode of inheritance. This mutation has not been described in RS yet. Blind LE was enucleated because of dolorous neovascular glaucoma. FA of RE shows excessive areas of capillary nonperfusion with vascular abnormalities and exudation. After the photocoagulation, the visual acuity (VA) on RE remains 0.9 at the age of 7 years. CONCLUSIONS: RS is an extremely rare condition.  The initial symptomatology could be ophthalmological or hematological. The positive finding of TINF2 gene mutation helped in establishing the correct diagnosis. The ischemic retinopathy was successfully treated by photocoagulation (Fig. 6, Ref. 6). Text in PDF www.elis.sk.

A novel heterozygous variant in ERLIN2 causes autosomal dominant pure hereditary spastic paraplegia.

BACKGROUND AND PURPOSE: Hereditary spastic paraplegias (HSPs) are clinically and genetically heterogeneous monogenic disorders. To date, nearly 70 genes are known to be causative. The aim of this project was to identify the genetic cause of autosomal dominantly inherited pure HSP in two large, unrelated non-consanguineous families. METHODS: The two families were characterized clinically and selected members underwent whole exome sequencing. Potentially disease-causing variants were confirmed by Sanger sequencing and their functional consequences on protein function were predicted by bioinformatic prediction tools. RESULTS: The patients presented with pure spastic paraplegia with age of onset between 9 and 46 years. In both families, a novel heterozygous missense variant in ERLIN2, c.386G>C; p.Ser129Thr, was the only potentially pathogenic variant identified that segregated with the disease. CONCLUSIONS: Biallelic variants in ERLIN2 are known to cause recessive HSP type SPG18. Here, the first two families with an autosomal dominant, pure form of HSP caused by a novel ERLIN2 heterozygous missense variant are described. These findings expand the mutational and inheritance spectrum of SPG18. ERLIN2 variants should also be considered in the diagnostic evaluation of patients with autosomal dominant HSP.

Combined PET/MRI: Global Warming-Summary Report of the 6th International Workshop on PET/MRI, March 27-29, 2017, Tübingen, Germany.

The 6th annual meeting to address key issues in positron emission tomography (PET)/magnetic resonance imaging (MRI) was held again in Tübingen, Germany, from March 27 to 29, 2017. Over three days of invited plenary lectures, round table discussions and dialogue board deliberations, participants critically assessed the current state of PET/MRI, both clinically and as a research tool, and attempted to chart future directions. The meeting addressed the use of PET/MRI and workflows in oncology, neurosciences, infection, inflammation and chronic pain syndromes, as well as deeper discussions about how best to characterise the tumour microenvironment, optimise the complementary information available from PET and MRI, and how advanced data mining and bioinformatics, as well as information from liquid biomarkers (circulating tumour cells and nucleic acids) and pathology, can be integrated to give a more complete characterisation of disease phenotype. Some issues that have dominated previous meetings, such as the accuracy of MR-based attenuation correction (AC) of the PET scan, were finally put to rest as having been adequately addressed for the majority of clinical situations. Likewise, the ability to standardise PET systems for use in multicentre trials was confirmed, thus removing a perceived barrier to larger clinical imaging trials. The meeting openly questioned whether PET/MRI should, in all cases, be used as a whole-body imaging modality or whether in many circumstances it would best be employed to give an in-depth study of previously identified disease in a single organ or region. The meeting concluded that there is still much work to be done in the integration of data from different fields and in developing a common language for all stakeholders involved. In addition, the participants advocated joint training and education for individuals who engage in routine PET/MRI. It was agreed that PET/MRI can enhance our understanding of normal and disrupted biology, and we are in a position to describe the in vivo nature of disease processes, metabolism, evolution of cancer and the monitoring of response to pharmacological interventions and therapies. As such, PET/MRI is a key to advancing medicine and patient care.

Mutations in the sodium channel gene SCN2A cause neonatal epilepsy with late-onset episodic ataxia.

Mutations in SCN2A cause epilepsy syndromes of variable severity including neonatal-infantile seizures. In one case, we previously described additional childhood-onset episodic ataxia. Here, we corroborate and detail the latter phenotype in three further cases. We describe the clinical characteristics, identify the causative SCN2A mutations and determine their functional consequences using whole-cell patch-clamping in mammalian cells. In total, four probands presented with neonatal-onset seizures remitting after five to 13 months. In early childhood, they started to experience repeated episodes of ataxia, accompanied in part by headache or back pain lasting minutes to several hours. In two of the new cases, we detected the novel mutation p.Arg1882Gly. While this mutation occurred de novo in both patients, one of them carries an additional known variant on the same SCN2A allele, inherited from the unaffected father (p.Gly1522Ala). Whereas p.Arg1882Gly alone shifted the activation curve by -4 mV, the combination of both variants did not affect activation, but caused a depolarizing shift of voltage-dependent inactivation, and a significant increase in Na(+) current density and protein production. p.Gly1522Ala alone did not change channel gating. The third new proband carries the same de novo SCN2A gain-of-function mutation as our first published case (p.Ala263Val). Our findings broaden the clinical spectrum observed with SCN2A gain-of-function mutations, showing that fairly different biophysical mechanisms can cause a convergent clinical phenotype of neonatal seizures and later onset episodic ataxia.

GBA-associated parkinsonism and dementia: beyond α-synucleinopathies?

BACKGROUND AND PURPOSE: To date the role of GBA mutations beyond α-synucleinopathies in the parkinsonism-dementia spectrum is still unclear. The aim of the study was to screen for GBA mutations in progressive supranuclear palsy (PSP), corticobasal syndrome (CBS), primary progressive aphasia (PPA) and the behavioural variant of frontotemporal dementia (bvFTD). METHODS: In all, 303 patients with a clinical diagnosis of PSP (n = 157), CBS (n = 39), PPA (n = 35) and bvFTD (n = 72) and 587 neurologically healthy controls were screened for the most common GBA mutations. RESULTS: GBA mutations were detected in one healthy control and four patients with a clinical diagnosis of PSP (n = 1), probable CBS (n = 2) and PPA (n = 1, with concomitant C9orf72 expansion). Overall the prevalence of GBA mutations was low in non-α-synucleinopathies but significantly higher in the CBS subgroup compared to controls. CONCLUSION: Although numbers are small, our findings indicate that the clinical phenotype of GBA-associated neurodegenerative disease is more heterogeneous than previously assumed, including phenotypes not usually associated with underlying α-synucleinopathies. This may be of relevance, once causal therapeutic strategies for GBA-associated neurodegenerative disease are developed.

Variability in hepatic expression of organic anion transporter 7/SLC22A9, a novel pravastatin uptake transporter: impact of genetic and regulatory factors.

Human organic anion transporter 7 (OAT7, SLC22A9) is a hepatic transport protein poorly characterized so far. We therefore sought to identify novel OAT7 substrates and factors contributing to variable hepatic OAT7 expression. Using OAT7-expressing cells, pravastatin was identified as a substrate. Hepatic SLC22A9/OAT7 mRNA and protein expression varied 28-fold and 15-fold, respectively, in 126 Caucasian liver samples. Twenty-four variants in SLC22A9 were genotyped, including three rare missense variants (rs377211288, rs61742518, rs146027075), which occurred only heterozygously. No variant significantly affected hepatic SLC22A9/OAT7 expression. The three missense variants, however, showed functional consequences when expressed in vitro. Hepatic nuclear factor 4-alpha (HNF4α) emerged as a major transcriptional regulator of SLC22A9 by a series of in silico and in vitro analyses. In conclusion, pravastatin is the first identified OAT7 drug substrate. Substantial inter-individual variability in hepatic OAT7 expression, majorly driven by HNF4α, may contribute to pravastatin drug disposition and might affect response.The Pharmacogenomics Journal advance online publication, 4 August 2015; doi:10.1038/tpj.2015.55.

A new case of UDP-galactose transporter deficiency (SLC35A2-CDG): molecular basis, clinical phenotype, and therapeutic approach.

Congenital disorders of glycosylation (CDG) are a group of hereditary metabolic diseases characterized by abnormal glycosylation of proteins and lipids. Often, multisystem disorders with central nervous system involvement and a large variety of clinical symptoms occur. The main characteristics are developmental delay, seizures, and ataxia. In this paper we report the clinical and biochemical characteristics of a 5-year-old girl with a defective galactosylation of N-glycans, resulting in developmental delay, muscular hypotonia, epileptic seizures, inverted nipples, and visual impairment. Next generation sequencing revealed a de novo mutation (c.797G > T, p.G266V) in the X-chromosomal gene SLC35A2 (solute carrier family 35, UDP-galactose transporter, member A2; MIM 300896). While this mutation was found heterozygous, random X-inactivation of the normal allele will lead to loss of normal SLC35A2 activity in respective cells. The functional relevance of the mutation was demonstrated by complementation of UGT-deficient MDCK-RCA(r) and CHO-Lec8 cells by normal UGT-expression construct but not by the mutant version. The effect of dietary galactose supplementation on glycosylation was investigated, showing a nearly complete normalization of transferrin glycosylation.

[Hereditary diffuse leukencephalopathy with spheroids: a microgliopathy due to CSF1 receptor impairment]. / Hereditäre diffuse Leukenzephalopathie mit Sphäroiden : Eine Mikrogliopathie durch Fehlfunktion des CSF1-Rezeptors.

Hereditary diffuse leukencephalopathy with spheroids (HDLS) is a rare progressive form of leukodystrophy with variable clinical presentation and little known pathophysiology. Characteristic pathological features at brain biopsy or postmortem can support the diagnosis. The genetic basis of HDLS was elusive until 2011 when mutations in the colony-stimulating factor 1 receptor (CSF1R) gene were identified as the cause. Mutations in the CSF1R gene had previously been associated with tumor development, including hematological malignancies. We report three patients with HDLS who carried missense mutations in the CSF1R gene, two of them novel (p.L582P and p.V383L). Particularly in younger patients with rapid cognitive decline and/or leukencephalopathy of unknown origin, HDLS appears to be more common than previously thought. Various compounds acting on the CSF1 receptor are available from the treatment of hemato-oncological malignancies, so novel therapeutic approaches could be developed for this devastating condition.

[Genetic diagnostic testing in inherited retinal dystrophies]. / Genetische diagnostik bei erblichen netzhautdystrophien.

Inherited retinal dystrophies are clinically and genetically highly heterogeneous. They can be divided according to the clinical phenotype and course of the disease, as well as the underlying mode of inheritance. Isolated retinal dystrophies (i.e., retinitis pigmentosa, Leber's congenital amaurosis, cone and cone-rod dystrophy, macular dystrophy, achromatopsia, congenital stationary nightblindness) and syndromal forms (i.e., Usher syndrome, Bardet-Biedl syndrome) can be differentiated. To date almost 180 genes and thousands of distinct mutations have been identified that are responsible for the different forms of these blinding illnesses. Until recently, there was no adequate diagnostic genetic testing available. With the development of the next generation sequencing technologies, a comprehensive genetic screening analysis for all known genes for inherited retinal dystrophies has been established at reasonable costs and in appropriate turn-around times. Depending on the primary clinical diagnosis and the presumed mode of inheritance, different diagnostic panels can be chosen for genetic testing. Statistics show that in 55-80 % of the cases the genetic defect of the inherited retinal dystrophy can be identified with this approach, depending on the initial clinical diagnosis. The aim of any genetic diagnostics is to define the genetic cause of a given illness within the affected patient and family and thereby i) confirm the clinical diagnosis, ii) provide targeted genetic testing in family members, iii) enable therapeutic intervention, iv) give a prognosis on disease course and progression and v) in the long run provide the basis for novel therapeutic approaches and personalised medicine.