Heterozygote Missense Mutation Research Articles

Clinical Presentation and WES Analysis of a Large Iranian Pedigree in Five Successive Generation Affected to Sever Multiple Synostosis 2 (SYNS2, Farhud Type)

Background: Bone Morphogenetic Proteins and the related Growth and Differentiation Factors (GDFs) are much conserved signaling proteins. GDF5 is pivotal for skeletal development. Several skeletal dysplasia and malformation syndromes are known as a result of mutations in GDF5. Multiple Synostosis Syndrome2 (SYNS2) is characterized by tarsal-carpal coalition, humeroradial synostosis, brachydactyly, and proximal symphalangism. In this study, we analyzed a large Iranian pedigree affected with a new type of SYNS2 (Farhud Type) in five successive generations. Methods: In this family-based study (1982-2022), Genetic linkage analysis of the pedigree (58affected, 62healthy) excluded the locus on chromosome 17q21-q22 in our previous study. Thus, we focused on 20q11.22 locus and GDF5 gene. Genetic investigations were performed on 16 patients with SYNS2 and 40 healthy individuals. Results: Whole-exome-sequencing results identified a heterozygote missense mutation in exon2 of GDF5 (NG_008076.1:g.9239G>A, NM_000557.2:c.1424G>A, S475N, rs121909347). This mutation was found in all patients but not in the unaffected individuals. This missense mutation is notable because S475 is strictly conserved among different species, and it is located in a highly conserved and active mature domain of GDF5 (phyloP100way=7.64). The corresponding defect in GDF5 may have unknown interaction with normal active 3rd and 4th structure of the product. Further bioinformatics study (amino acid multiple alignments) showed that the S475 is a much-conserved residue in many different species. Conclusion: These results introduce a new role of GDF5 in pathogenesis of a SYNS2 (Farhud Type), considered in genetic counseling, prenatal diagnosis, and as a potential target for molecular therapy, if possible.

Coexistence of antithrombin deficiency and suspected inferior vena cava atresia in an adolescent and his mother \u2013 case report and clinical implications

BackgroundAntithrombin deficiency (ATD) is an autosomal dominant thrombophilia presenting with varying phenotypes. In pediatric patients with ATD, thrombosis typically develops during the neonatal period or adolescence. However, to date there are no consistent recommendations on the therapeutic management of children with ATD. Inferior vena cava atresia (IVCA) belongs to a range of congenital or acquired vena cava malformations and is described as an independent risk factor for thrombosis.The present case report explores two cases of combined ATD and IVCA in an adolescent and his mother.Case presentationA 14-year-old male presented with extensive deep venous thromboses (DVTs) of both lower extremities as well as an IVCA. The patient had previously been diagnosed with an asymptomatic ATD without therapeutic consequences at that time. His mother was suffering from an ATD and had herself just been diagnosed with IVCA, too.The DVTs in the adolescent were treated by systemic anticoagulation and catheter-directed local thrombolysis causing favourable results. Yet, despite adequate oral anticoagulation the DVTs in both lower extremities reoccurred within 1 week after the patient was discharged from hospital. This time, thrombolysis could not be fully achieved. Surprisingly, probing and stenting of the IVCA was achieved, indicating an acquired IVCA which could have occurred after undetected thrombosis in early childhood.Genetic analyses showed the same mutation causing ATD in both son and mother: heterozygote missense mutation c.248 T > C, p.(Leu83Pro), within the heparin binding domain of antithrombin. This mutation was never reported in mutation databases before.ConclusionsTo our knowledge this is the first case report discussing combined ATD and IVCA in two family members. Since ATDs present with clinical heterogeneity, taking a thorough family history is crucial for the anticipation of possible complications in affected children and decisions on targeted diagnostics and therapeutic interventions. Affected families must be educated on risk factors and clinical signs of thrombosis and need an immediate diagnostic workup in case of clinical symptoms. IVCA in patients with ATD could occur due to thrombotic occlusion at a very early age. Therefore, in case of family members with IVCA and ATD ultrasound screening in newborns should be considered.

Co-occurrence of Moyamoya syndrome and Kartagener syndrome caused by the mutation of DNAH5 and DNAH11: a case report

BackgroundKartagener syndrome is an autosomal recessive inherited disorder of primary ciliary dyskinesia. Moyamoya syndrome refers to a moyamoya angiopathy associated with other neurological and/or extra-neurological symptoms, or due to a well identified acquired or inherited cause. We herein reported a case of a 48-year-old woman who was favored the diagnosis of Kartagener syndrome and moyamoya syndrome. The whole genome sequencing and bioinformatics analysis showed a homozygotic nonsense mutation in the dynein, axonemal, heavy chain (DNAH) 5 gene, and heterozygotic missense mutation in the DNAH11 gene. This is the first report of the co-occurrence of the two rare diseases.Case presentationA case of a 48-year-old woman was presented with hemiplegia and slurred speech. The magnetic resonance imaging of the brain confirmed acute cerebral infarction in the right basal ganglia region, semi-oval center, insular lobe, and frontal parietal lobe. The electrocardiogram showed inverted “P” waves in L1 and AVL on left-sided chest leads and computed tomography scan of the chest showed bronchiectasis changes, cardiac shadow and apex on the right side, and situs inversus of aortic arch position. The digital subtraction angiography showed inversion of the aortic arch, and bilateral internal carotid arteries are occluded from the ophthalmic segment. The clinical, radiological, and laboratory findings made the diagnosis of Kartagener syndrome and moyamoya syndrome. The whole genome sequencing and bioinformatics analysis showed a homozygotic nonsense mutation in DNAH5 gene, and heterozygotic missense mutation in the DNAH11 gene.ConclusionThe combined mutation of DNAH5 and DNAH11 may lead to the overlapping dysfunction of motile and nonmotile cilia, which contribute to the co-occurrence of Kartagener syndrome and moyamoya syndrome. Our report deserves further confirm by more case reports.

SUN-032 Digenic Inheritance of PCSK1 and CHD7 Mutations in PAX4 Homozygous Diabetic Male with Normosmic Hypogonadotropic Hypogonadism

Background: Normosmic congenital hypogonadotropic hypogonadism denotes Kallmann syndrome not associated with anosmia or hyposmia. Over the past few years, the availability of next-generation sequencing has started to unravel the complex molecular basis of congenital hypogonadotrophic hypogonadism including digenic or oligogenic pathogenecity in addition to classic monogenic causality (1). Clinical Case: A 22-year-old male patient was referred to the endocrine clinic in 2018 with recent -onset hyperglycemia. His weight was 82.2 kg with a height of 180 cm (BMI of 25.3 kg/m2). Physical examination revealed small testes, micropenis, and no axillary and pubic terminal hair. His smell sense was intact. His hormonal test reveals low testosterone (0.10 ng/mL) and low free testosterone (0.65 pg/mL) levels with inappropriately low gonadotrophins levels. Secretion of LH and FSH increased 2-fold after GnRH stimulation. His bone age was 13-years 6-months old, and brain magnetic resonance imaging showed the presence of olfactory bulbs, and unremarkable findings except for small size of the pituitary gland. There were no signs associated with CHARGE syndrome (coloboma ocular, heart defects, atresia or stenosis of the choanae, retardation of growth and/or development, genitourinary anomalies, and ear abnormalities). Biochemical investigation demonstrated high serum glucose level and high HbA1c (13.8%). To identify variants to cause the phenotype of the proband, we adopted trio-based whole exome sequencing (WES) and candidate gene approach. Candidate genes was listed from the orphanet (https://www.orpha.net). WES of the proband revealed the presence of heterozygote missense mutations of the CHD7 gene (c.6107C>T, p.Pro2036Leu, rs369543203) and PCSK1 gene (c.239G>A, p.Arg80Gln, rs1799904). The missense variants were predicted to have a damaging effect on the encoded protein, by SIFT and PolyPhen-2 analyses. Genetic analyses of his family revealed that his father had the same heterozygote missense mutations of the CHD7 gene, but wild type of PCSK1. Proband’s mother had the same heterozygote missense mutations of PCSK1, but wild type of CHD7. Furthermore, the proband had homozygote missense mutation of PAX4 (c.575G>A, p.Arg192His, rs2233580) known as maturity-onset diabetes of the young (MODY) 9 gene. Both parents have the same but heterozygous mutation of PAX4 p.Arg192His, and pre-diabetic range of hyperglycemia. Conclusion: This is the first case demonstrating digenic inheritance of mutations in PCSK1 and CHD7 as a potential cause of normosmic hypogonadotrophic hypogonadism, interestingly in PAX4 homozygous diabetic male. Reference: (1) Maione L, et al. Genetic counseling for congenital hypogonadotropic hypogonadism and Kallmann syndrome: new challenges in the era of oligogenism and next-generation sequencing. Eur J Endocrinol. 2018;178(3):R55-R80.

Investigation of MYO15A and MYO7A Mutations in Iranian Patients with Nonsyndromic Hearing Loss

Background Hearing loss (HL) is the most common sensory disorder in humans, which affects individuals in both inherited and acquired forms. MYO15A and MYO7A gene mutations have a significant role in the development of deafness. In this study, we assessed the prevalence of MYO15A and MYO7A mutations in one hundred non-relative deaf Iranians. Materials and methods: The existence of MYO15A and MYO7A mutations were assessed using the tetra-primer ARMS-PCR method, High Resolution Melting (HRM) and sequencing method. Results: A heterozygote missense mutation, p.V2135L (c.6403G > T) in the MYO15A gene, was found in a patient using the sequencing method. Conclusion: These results explain the negligible prevalence of selected mutations among Iranian patients. Identifying common mutations in patients of an ethnic group can reduce the financial costs and time needed for identifying the causes of deafness.

A Novel Compound Heterozygous Mutation in ABCB4 Gene Leading to Cholelithiasis, Progressive Familial Intrahepatic Cholestasis (Type 3), and Cirrhosis in a Child

AbstractProgressive familial intrahepatic cholestasis (PFIC) is a heterogeneous group of autosomal recessive disorders of childhood which presents with intermittent or progressive episodes of cholestasis, with jaundice and pruritus as most common presenting symptoms. PFIC type 3 occurs due to mutations in the ABCB4 gene, mutation in this gene has wide spectrum of features which include intrahepatic stones, cholelithiasis, PFIC type 3, and intrahepatic cholestasis of pregnancy. Here, we are reporting a peculiar case of young male adolescent with novel variant compound heterozygote missense mutation in ABCB4 gene who had gall stone as initial symptom, followed by symptoms of PFIC and eventually decompensated chronic liver disease.

Genetic Diagnosis if a Lethal Form of Autosomal Recessive Polycystic Kidney Disease

Background Autosomal recessive polycystic kidney disease (ARPKD; OMIM number 263200) is a severe early onset hereditary form of polycystic kidney and liver disease. Case Report In the current study, we present a consanguineous couple with a history of an affected son with polycystic kidney disease (PKD), hepatic failure and epileptic seizures who died at the age of 8 months. Both parents were heterozygote for a missense mutation in PKHD1 gene (NM_170724, c.9107T>G, p.V3036G). Conclusion Unlike previous studies which showed the association between missense mutations of PKHD1 gene and mild phenotype of ARPKD, we have demonstrated the presence of a certain heterozygote missense mutation in parents of a patient affected with lethal form of disorder. Such phenotypic variations should be considered in genetic counseling of families especially those seeking prenatal diagnosis.

A novel PAX9 mutation causing oligodontia

IntroductionAn extended family presenting with several members affected by developmentally missing teeth was investigated by analysis of the MSX1 and PAX9 genes. Materials and methodsSaliva samples were collected and DNA extracted. Primers were designed to span the exons and intron-exon junctions of the MSX1 and PAX9 genes. These primers were optimised using gradient Polymerase Chain Reaction. The amplified fragments were sent for Sanger sequencing Resultsa novel heterozygote missense mutation in exon 3 of PAX9 (c.296G > C, p.A99P), was found in two severely affected members of the family as well as a potentially pathogenic heterozygote variant (c.119C > G, p.A40G) in exon 1 of the MSX1 gene. ConclusionThe PAX9 A99P mutation is in the DNA binding domain and is predicted to be pathogenic.

Atypical presentation of infantile-onset farber disease with novel ASAH1 mutations.

Farber disease is a very rare autosomal recessive disease caused by mutation of ASAH1 that results in the accumulation of ceramide in various tissues. Clinical symptoms of classic Farber disease comprise painful joint deformity, hoarseness of voice, and subcutaneous nodules. Here, we describe a patient with Farber disease with atypical presentation of early onset hypotonia, sacral mass, congenital heart disease, and dysmorphic face since birth. Severe cognitive disability, failure to gain motor skills, failure to thrive, and joint contractures developed. Using whole-exome sequencing, we identified the compound heterozygote missense mutations of ASAH1 (p.R333C and p.G235R). Because of the diagnostic delay, she underwent sacral mass excision, which revealed enlarged lysosomes and zebra bodies. We report an atypical presentation of Farber disease with her pathology and associated genetic defect. This case expands the phenotypic spectrum of Farber disease to include novel mutations of ASAH1, which pose a diagnostic challenge. We also discuss the clinical utility of whole-exome sequencing for diagnosis of ultra-rare diseases. © 2016 Wiley Periodicals, Inc.

Mutational analysis of SCN1A gene in Chinese families with generalized epilepsy with febrile seizures plus

Objective To investigate the gene mutations of SCN1A in the families with generalized epilepsy with febrile seizures plus (GEFS+ ) and analyze the genotype-phenotype correlations in GEFS+ families. Methods Genomic DNA was extracted from peripheral blood lymphocytes of the probands and other available members in the GEFS+ families.The phenotypes of the affected members were analyzed.The coding regions and flanking intronic regions of the SCN1A gene were screened for mutations using PCR and direct DNA sequencing. Results Two in 17 families(11.76%) were found with novel SCN1A mutations(C142T, S573R), presenting heterozygote missense mutations in exon 3 and exon 11 located in highly conserved region.The above 2 mutations had not been reported.The proband and other affected members in pedigree 1 all carried the mutation(C142T). Their clinical phenotype included febrile seizures(FS) and FS plus(FS+ ) with generalized tonic-clonic seizures and the penetrance rate was about 75.0%(3/4 cases). The phenotype of the proband in pedigree 2 harbored S573R were FS+ with partial seizures and the penetrance rate was about 66.7%(2/3 cases). Conclusions Two novel missense mutations were identified in the GEFS+ families, which were consistent with autosomal dominant inheritance with incomplete penetrance.C142T located in the S6 transmembrane regions at domain D1 and S573R located between S5-S6 segment at domain D4 in the voltage-gated sodium channel.Two families harbored different genetic mutations, in which the affected members had different clinical phenotypes.SCN1A is one of the pathogenic gene in Chinese GEFS+ patients and the genotypes of GEFS+ family is associated with the clinical phenotypes. Key words: Generalized epilepsy with febrile seizures plus; SCN1A gene; Mutation

P39 – 2771: Variable phenotype in epilepsy caused by KCNQ2 mutations

Objective KCNQ2 mutations have been described in infants with benign familial neonatal seizures but also in cases of epileptic encephalopathy. The objective of our study is to investigate the phenotype of KCNQ2-related epilepsy. Methods We reviewed initial seizure types, EEG and MRI data of children with infantile onset epilepsy caused by KCNQ2 mutation followed in the Pediatric Epilepsy Unit in the University Hospitals of Leuven. Results We describe 10 infants diagnosed with 9 different heterozygote missense mutations in KCNQ2. Five cases had a familial history of neonatal seizures, 5 cases were de novo. Onset of epilepsy occurred before 2 months in all cases. The predominant seizure type was tonic with deviaton of the head and eyes in 6 patients, clonic in 4 patients and co-occurence of apnea with cyanosis in 4 patients. Normal background EEG was found in 3/5 familial cases. The infants with encephalopathy showed a severely abnormal background activity with a burst-suppression pattern in 2, multifocal epileptic activity in 2 and normal background EEG in 1 case. Neuro-imaging showed no abnormalities in 9 cases. Normal developmental outcome was seen in 4 familial cases, only 1 had mild developmental delay. The encephalopathies showed moderate developmental delay in 1 and severe developmental delay in 4 cases respectively. All epileptic encephalopathies could initially be classified as drug resistant, but at last follow-up 3 of them were seizure free on medication. Conclusion There is an important phenotypical variability in patients with KCNQ2-related epilepsy. Early start of epilepsy is common, but clinical and electrographical phenotype is very variable. Neuro-imaging is not contributive. Familial occurrence has a normal developmental outcome in most cases. The majority of the de novo mutations showed a bad developmental outcome. Our results further suggest that KCNQ2 should be screened for in the diagnostic workup of early onset infantile seizures. KCNQ2 mutations have been described in infants with benign familial neonatal seizures but also in cases of epileptic encephalopathy. The objective of our study is to investigate the phenotype of KCNQ2-related epilepsy. We reviewed initial seizure types, EEG and MRI data of children with infantile onset epilepsy caused by KCNQ2 mutation followed in the Pediatric Epilepsy Unit in the University Hospitals of Leuven. We describe 10 infants diagnosed with 9 different heterozygote missense mutations in KCNQ2. Five cases had a familial history of neonatal seizures, 5 cases were de novo. Onset of epilepsy occurred before 2 months in all cases. The predominant seizure type was tonic with deviaton of the head and eyes in 6 patients, clonic in 4 patients and co-occurence of apnea with cyanosis in 4 patients. Normal background EEG was found in 3/5 familial cases. The infants with encephalopathy showed a severely abnormal background activity with a burst-suppression pattern in 2, multifocal epileptic activity in 2 and normal background EEG in 1 case. Neuro-imaging showed no abnormalities in 9 cases. Normal developmental outcome was seen in 4 familial cases, only 1 had mild developmental delay. The encephalopathies showed moderate developmental delay in 1 and severe developmental delay in 4 cases respectively. All epileptic encephalopathies could initially be classified as drug resistant, but at last follow-up 3 of them were seizure free on medication. There is an important phenotypical variability in patients with KCNQ2-related epilepsy. Early start of epilepsy is common, but clinical and electrographical phenotype is very variable. Neuro-imaging is not contributive. Familial occurrence has a normal developmental outcome in most cases. The majority of the de novo mutations showed a bad developmental outcome. Our results further suggest that KCNQ2 should be screened for in the diagnostic workup of early onset infantile seizures.

Two novel heterozygote missense mutations of the ADAMTS13 gene in a child with recurrent thrombotic thrombocytopenic purpura.

Thrombotic thrombocytopenic purpura is a rare, life-threatening disease characterised by microangiopathic haemolytic anaemia, thrombocytopenia and symptoms related to organ ischaemia, mainly involving the brain and the kidney. It is associated with a deficiency of ADAMTS13, a plasma metalloprotease that cleaves von Willebrand factor. The congenital form (Upshaw-Schulman syndrome) is rare and is associated with mutations of the ADAMTS13 gene on chromosome 9q34. The clinical symptoms of congenital thrombotic thrombocytopenic purpura are variable, with some patients developing their first episode during the neonatal period or childhood and others becoming symptomatic in adulthood. We describe a case of thrombotic thrombocytopenic purpura, who presented to our attention with a relapsing form of the disease: the first episode occurred at the age of 13 months. Phenotype and genotype tests were performed in the patient and his family. The undetectable level of ADAMTS13 in the patient was caused by two novel heterozygote missense mutations on the ADAMTS13 gene: one mutation is c.788C > T (p.Ser263Phe) on exon 7 and the second is c.3251G > A (p.Cys1084Tyr) on exon 25 of the ADAMTS13 gene. All the relatives who have been investigated were found to carry one of these missense mutations in a heterozygous state. Although Upshaw-Schulman syndrome is a rare disease, it should be considered in all children with thrombocytopenia and jaundice in the neonatal period. In fact, once a child is confirmed to carry mutations of the ADAMTS13 gene causing early thrombotic thrombocytopenic purpura, prophylactic treatment should be started to avoid recurrence of symptoms. Genotype tests of relatives would also be important for those women in the family who could be carriers of ADAMTS13 mutations, particularly during pregnancy.

Multimodal fundus imaging in fundus albipunctatus with RDH5 mutation: a newly identified compound heterozygous mutation and review of the literature

The aim of this study was to describe multimodal retinal imaging of fundus albipunctatus (FA) with the newly identified compound heterozygous RDH5 mutation and to review the relevant literature. Five family members were examined, and the RDH5 gene was analyzed by direct sequencing. The clinical features and genetic study of FA are reviewed. The proband had a compound heterozygotic missense mutation of Cys59Ser (TGC → AGC) and a nonsense mutation of Trp95ter (TGG → TGA) in the RDH5 gene. Fundus examination revealed diffuse yellow flecks with foveal sparing. Infrared reflectance (IR) imaging showed multiple discrete round lesions, and fundus autofluorescence (FAF) imaging showed decreased autofluorescence. In spectral domain optical coherence tomography (SD-OCT), the lesions spanned across the retinal pigment epithelium complex and the photoreceptor inner segment ellipsoid band. The outer nuclear layer thickness is decreased compared to normal control. Electroretinography (ERG) showed improved dark-adapted responses after a prolonged 2.5-h dark adaptation. The fundi of the patient's son and daughter both appeared unremarkable. The clinical findings, differential diagnosis, and genetic studies of these features are reviewed. This is the first time that IR imaging of this disease has been reported; IR imaging showed more detail than did FAF imaging. Although retinal imaging (fundus photographs, FAF, IR, SD-OCT) of FA showed characteristic findings, ERG and genetic study remain the most reliable tests for making the diagnosis.

Genetic and clinical characteristics of head and neck paragangliomas in a chinese population

Head and neck paragangliomas (PGLs) are rare and frequently associated with germline mutations of the succinate dehydrogenase (SDH) genes, especially for familial cases. The purpose of the study was to explore genetic and clinical characteristics of head and neck PGLs in a Chinese population. Retrospective review. One hundred thirty-two patients who had undergone resection for head and neck PGLs between 1975 and 2010 were identified. Clinical characteristics and outcomes were reviewed. Analysis of the SDH genes was performed in 29 patients and one kindred with familial PGL to identify germline mutations in the SDHB, SDHC, and SDHD genes by direct DNA sequencing. There were 69 male (52.3%) and 63 female (47.76%) patients, with a mean age of 43.6 years (range, 13-72 years). Most lesions (61.4%) were PGLs of the carotid bifurcation. Others included jugular (25.0%), vagal (9.1%), and tympanic PGLs. Twenty-one patients (15.9%) had multiple PGLs, 25 patients (18.9%) had a malignant PGL, and 15 patients (11.4%) in four families were familial PGLs. Analysis of the SDH genes in 29 patients showed that four familial cases (including two patients) carried a heterozygotic missense mutation in SDHD. The mutation was W43X, located in SDHD-exon 2. Four sporadic cases carried samesense germline mutations in SDHB-exon 1, and they were all malignant PGLs. Multifocal occurrence, potential malignancy, and genetic aspect should be considered in patients with head and neck PGLs. The high frequency of founder mutations in SDHB suggests a higher prevalence of malignancy, and the SDHD mutation is usually associated with familial cases.

Mutations in the Nuclear Encoded Novel Mitochondrial Protein CHCHD10 Cause an Autosomal Dominant Mitochondrial Myopathy (IN7-2.002)

Objective: To report a novel causative gene for an autosomal dominant mitochondrial myopathy. Background Mitochondrial myopathies belong to a larger group of systemic diseases caused by morphological or biochemical abnormalities of mitochondria. Mitochondrial disorders can be caused by mutation either in the mitochondrial or in the nuclear genome. Design/Methods: Patients are part of previously reported Hispanic kindred with autosomal dominant mitochondrial myopathy (Heiman-Patterson et al 1997). Linkage analysis was established using fluorescent microsatellite markers and illumina genome wide SNP markers. Candidate gene was identified using MitoCarta (Vamsi K. Mootha, personal communication). Candidate gene was sequenced using Beckman Coulter CEQ 8000 DNA analysis system. The cDNA of wild type, single and double mutant gene were cloned in pCMV-Myc vector and co-transfected with pDsRed2-mito in HEK293 cells. The co-localization was monitored with confocal microscopy. Results: In this five generation Hispanic family we established linkage to chromosome 22q11. Using the tools of integrative gneomics, we established CHCHD10/ C22orf16 as the high scoring mitochondrial candidate gene in our minimal candidate region. Sequence analysis revealed a double heterozygote missense mutation in this gene. These two mutations segregated with disease phenotype and were absent in 500 Caucasians and Hispanic non affected controls. Both wild types, single and double mutant proteins co-localized with mitochondria. Conclusions: We identified a new nuclear encoded mitochondrial gene ( CHCHD10 ) as the cause of an autosomal dominant mitochondrial myopathy. CHCHD10 encodes a non characterized 142 aa protein with a target mitochondrial signaling peptide and a conserved CHCH domain. This CHCH domain is present in many intermembrane space proteins, such as the family of small Tim proteins. The exact function of this protein remains to be determined. Our findings expands the spectrum of mitochondrial myopathies caused by nuclear gene dysfunction. Disclosure: Dr. Ajroud-Driss has nothing to disclose. Dr. Fecto has nothing to disclose. Dr. Ajroud has nothing to disclose. Dr. Siddique has nothing to disclose.

Percutaneous ultrasound-guided radiofrequency ablation treatment and genetic testing for renal cell carcinoma with Von Hippel-Lindau disease

Percutaneous ultrasound-guided radiofrequency ablation is increasingly being studied in the treatment of renal tumors. Because percutaneous ultrasound-guided radiofrequency ablation is a minimally invasive and nephron-sparing procedure, it is ideally suited for patients with a single kidney, multiple tumors, or contraindications to conventional surgery. We report on a patient with Von Hippel-Lindau (VHL) disease who had multicentric tumors in the single kidney that was successfully treated with percutaneous ultrasound-guided radiofrequncy ablation. The one-year follow-up showed that there was no local recurrence or metastasis. And genetic testing showed the patient had a T to G heterozygotic missense mutation at nucleotide 515 of VHL gene exon 1.

Multiple Acyl-CoA-dehydrogenase deficiency (MADD) — A novel mutation of electron-transferring-flavoprotein dehydrogenase ETFDH

This is the case of a 41year old man, suffering general weakness and elevated liver enzymes, sensitive to a treatment with riboflavin and coenzyme Q10. Tandem mass spectroscopy and molecular analysis reveal a multiple acyl-CoA-dehydrogenase deficiency (MADD) with two novel heterozygote missense mutations of the EFTDH gene.

The First Case of 3-Methylcrotonyl-CoA Carboxylase (MCC) Deficiency Responsive to Biotin

3-Methylcrotonylglycinuria is an inborn error of leucine catabolism with an autosomal recessive pattern of inheritance that results from a deficiency of 3-methylcrotonyl-CoA carboxylase (MCC). We report on a nine-year-old boy with severe psychomotor retardation who developed infantile spasms at the age of three weeks. Urine analysis at the age of two years revealed massive 3-methylcrotonylglycinuria and 3-hydroxyisovaleric aciduria suggesting MCC deficiency. Carnitine serum levels were decreased. Biotin therapy led to a dramatic decrease in the frequency of seizures, disappearance of hypsarrhythmia, and near normalisation of organic aciduria. Four months later a protein-restricted diet was introduced in addition and the boy remained clinically and metabolically stable. However, severe psychomotor delay persisted, and the seizures partially reoccurred. Biochemical findings showed partial MCC deficiency in cultured fibroblasts. Molecular genetic studies revealed a heterozygote missense mutation, MCCA-R385S, converting arginine to serine in a highly conserved region of the MCCA gene. This is the first patient with MCC deficiency caused by a heterozygote mutation and who demonstrated a substantial and sustained clinical and biochemical response to therapeutic doses of biotin. Sadly, this patient again also demonstrates that the main determinant of the outcome of even easily treatable metabolic diseases is timely diagnosis.

76 Abnormal ABCA3 Expression and Lamellar Bodies Formation in Newborns with Congenital Surfactant Deficiency.

Background: Besides surfactant protein B (SP-B), respiratory distress syndrome in term neonates is associated to mutations of ABCA3, a gene encoding a type II pneumocyte protein essential for intracellular surfactant metabolism.Study goal: To correlate mutations in surfactant-related genes with specific tissue/cell structural anomalies and alterations of surfactant-related protein expression.Methods: 4 neonates with primary, progressive respiratory failure unresponsive to exogenous surfactant. Optical microscopy (OM) on formalin-fixed lung biopsy: HE, PAS, Masson trichrome; immunohistochemestry with CD45, CD68, SP-B and SP-C antibodies; immunofluorescence with ABCA3 antibody. Electron microscopy (EM) on Karnowsky-fixed ultrathin sections. Direct sequencing of SP-B, SP-C and ABCA3 genes on PCR-amplified genomic DNA.Results: Case 1, 2 and 3 were term-born infants dead at 68, 48 and 55d; case 4 was a 32-week preterm alive with severe respiratory failure at 4 months. OM: All cases showed marked interstitial thickening with monocyte infiltrate, type II pneumocyte hyperplasia, intra-alveolar proteinaceous material and macrophage accumulation. SP-B and SP-C protein expression was normal. ABCA3, abundantly expressed with a cytoplasmic granular pattern in normal subjects, was either absent (1), low with a diffuse cytoplasmic pattern (2,4), or apparently normal (3). EM: In all cases, type II pneumocyte lamellar bodies appeared much smaller than normal and filled with homogenous material with an eccentric, denser inclusion. Pseudomyelin structures, corresponding to intracellular surfactant, were virtually absent. Molecular genetics: SP-B and SP-C gene sequences were normal. In the ABCA3 gene, homozygous frameshift (1) or double heterozygote missense mutations (2,3,4) were found.Conclusions: ABCA3 deficiency is a rare but relevant cause of progressive respiratory failure in newborns. Various recessive mutations are associated with this phenotype, leading in most cases to absent or aberrant ABCA3 protein expression and/or function. Whereas OM may be nonspecific, EM shows typical anomalies of the lamellar bodies that may contribute to early diagnosis.

Beta-catenin expression in pilomatrixomas. Relationship with beta-catenin gene mutations and comparison with beta-catenin expression in normal hair follicles.

beta-catenin functions in signal transduction in the Wnt signalling pathway, which has recently been implicated in hair follicle (HF) morphogenesis. beta-catenin gene mutations affecting exon 3 have been reported in a high percentage of human pilomatrixomas. However, the expression pattern of beta-catenin in human HFs and pilomatrixomas has not been reported. To analyse immunohistochemically the expression pattern of beta-catenin in normal anagen HFs and in 40 human pilomatrixomas. In 11 of these tumours we also studied exon 3 beta-catenin gene mutations by polymerase chain reaction and direct sequencing. As these mutations have been related to a replication error (RER) phenotype in other tumour types, we explored whether or not this association also occurs in pilomatrixomas. beta-catenin was expressed in the cell membranes of the outer and inner root sheaths and in matrix cells located at the base and periphery of the HF bulb. However, central matrix cells that differentiate into cortical cells, cortical and cuticular cells expressed beta-catenin in the nucleus, suggesting a role in signal transduction. In addition, some fibroblasts of the dermal papilla also showed nuclear expression of beta-catenin. All 40 analysed pilomatrixomas showed intense nuclear and cytoplasmic beta-catenin expression in proliferating matrix (basaloid) cells. In areas of maturation, transitional cells mainly showed cytoplasmic and membranous expression of beta-catenin, while only a few cells retained nuclear expression. Shadow or ghost cells did not show beta-catenin expression. Three of 11 tumours (26%) had beta-catenin mutations. All three had the same heterozygote mis-sense mutation: a G to T change affecting the first nucleotide at codon 32 (D32Y). None of the 11 tumours studied had a positive RER phenotype. Present and previous studies suggest that the Wnt/beta-catenin/Tcf-Lef pathway is activated in normal matrix cells of the HF to induce differentiation to the hair shaft. Additionally, the beta-catenin mutation in matrix cells of the HF stabilizes beta-catenin protein, which translocates into the nucleus, where it activates of gene transcription together with lymphoid enhancer factor-1 producing pilomatrixoma. These mutations occur without an underlying defect in DNA mismatch repair.