Variant In Heterozygous State Research Articles

Dementia associated with early‐onset Parkinson’s disease: Description of a family case in Colombia

AbstractBackgroundParkinson’s Disease (PD) is a motor neurodegenerative disorder of the dopaminergic neurons in the substantia nigra1. One of the frequent complications is dementia and often is a late symptom1,2. Some studies suggest that around 10% of patients with PD develop dementia per year2,3. Mutations in PLA2G6 are responsible of PARK14, an autosomal recessive L‐DOPA responsive dystonia/parkinsonism with early/adult onset4. This phenotype presents a high clinical variability, which consists in the occurrence of cerebral and cerebellar atrophy, iron accumulation in the basal ganglia, and cognitive decline4. In this study, we describe the genotype of two brothers diagnosed with early onset PD and a phenotype with FTD‐like characteristics.MethodA complete clinical evaluation consisting of geriatric, psychyatric, neurologic and neurpsychologic evaluation, was carried out in two affected male individuals, and their family. NGS was performed (PD targeted panel, WES, WGS) and MLPA on the two affected individuals.ResultThe two affected individuals were diagnosed around their thirties, presenting classic motor symptoms of PD. Subsequently, dementia associated to frontotemporal disease was diagnosed. No iron accumulation in the basal ganglia was found in either of the affected siblings. Genetic tests showed the pathogenic variant in heterozygous state c.2132C>G, p.Pro711Arg in PLA2G6 gene in the two affected brothers and their healthy mother.ConclusionAtypical frontotemporal dementia in two siblings with early‐onset PD is described. Additional studies should be performed to identify another variant or another gene in this family. Some studies have risen the hypothesis that even heterozygous PLA2G6 mutations may cause PARK144.

Identification of two novel RRM2B variants associated with autosomal recessive progressive external ophthalmoplegia in a family with pseudodominant inheritance pattern.

RRM2B encodes the p53-inducible small subunit (p53R2) of ribonucleotide reductase, a key protein for mitochondrial DNA (mtDNA) synthesis. Pathogenic variants in this gene result in familial mitochondrial disease in adults and children, secondary to a maintenance disorder of mtDNA. This study describes two patients, mother and son, with early-onset chronic progressive external ophthalmoplegia (PEO). Skeletal muscle biopsy from the latter was examined: cytochrome c oxidase (COX)-negative fibres were shown, and molecular studies revealed multiple mtDNA deletions. A next-generation sequencing gene panel for nuclear-encoded mitochondrial maintenance genes identified two unreported heterozygous missense variants (c.514 G > A and c.682 G > A) in the clinically affected son. The clinically affected mother harboured the first variant in homozygous state, and the clinically unaffected father harboured the remaining variant in heterozygous state. In silico analyses predicted both variants as deleterious. Cell culture studies revealed that patients' skin fibroblasts, but not fibroblasts from healthy controls, responded to nucleoside supplementation with enhanced mtDNA repopulation, thus suggesting an in vitro functional difference in patients' cells. Our results support the pathogenicity of two novel RRM2B variants found in two patients with autosomal recessive PEO with multiple mtDNA deletions inherited with a pseudodominant pattern.

IgD shapes the pre-immune naïve B cell compartment in humans.

B cell maturation and immunoglobulin (Ig) repertoire selection are governed by expression of a functional B cell receptor (BCR). Naïve B cells co-express their BCR as IgM and IgD isotype. However, the role of the additionally expressed IgD on naïve B cells is not known. Here we assessed the impact of IgD on naïve B cell maturation and Ig repertoire selection in 8 individuals from 3 different families with heterozygous loss-of-function or loss-of expression mutations in IGHD. Although naïve B cells from these individuals expressed IgM on their surface, the IGHD variant in heterozygous state entailed a chimeric situation by allelic exclusion with almost half of the naïve B cell population lacking surface IgD expression. Flow cytometric analyses revealed a distinct phenotype of IgD-negative naïve B cells with decreased expression of CD19, CD20 and CD21 as well as lower BAFF-R and integrin-β7 expression. IgD-negative B cells were less responsive in vitro after engaging the IgM-BCR, TLR7/9 or CD40 pathway. Additionally, a selective disadvantage of IgD-negative B cells within the T2 transitional and mature naïve B cell compartment as well as reduced frequencies of IgMlo/- B cells within the mature naïve B cell compartment lacking IgD were evident. RNA-Ig-seq of bulk sorted B cell populations showed an altered selection of distinct VH segments in the IgD-negative mature naïve B cell population. We conclude that IgD expression on human naïve B cells is redundant for generation of naïve B cells in general, but further shapes the naive B cell compartment starting from T2 transitional B cells. Our observations suggest an unexpected role of IgD expression to be critical for selection of distinct Ig VH segments into the pre-immune Ig repertoire and for the survival of IgMlo/- naïve B cells known to be enriched in poly-/autoreactive B cell clones.

The «Amish» NM_000256.3:c.3330+2T>G splice variant in MYBPC3 associated with hypertrophic cardiomyopathy is an ancient Swiss mutation

MYBPC3 is the most frequently mutated gene in hypertrophic cardiomyopathy (HCM). Several loss-of-function founder variants have been reported in MYBPC3 from various geographic regions, altogether suggestive of a modest or absent effect of these variants on reproductive fitness. One of them, a MYBPC3 splice variant, NM_000256.3:c.3330+2T > G, was first described in homozygous state in newborns presenting with a severe, recessive form of HCM among the Amish population and was later associated with adult-onset dominant HCM in heterozygous carriers. We here report this splice variant in heterozygous state in eight unrelated Swiss families with HCM, making it the most prevalent cardiomyopathy variant in western Switzerland. This variant was identified in patients using targeted (n = 5) or full-genome sequencing (n = 3). Given the prevalence of this variant in the Old Order Amish, Mennonites and Swiss populations, and given that both Amish and Mennonites founders originated from the Bern Canton in Switzerland, the MYBPC3, NM_000256.3:c.3330+2T > G variant appears to be of Swiss origin. Neighboring regions that hosted the first Amish settlements (Alsace, South Germany) should be on the lookout for that variant. The existence of MYBPC3 founder variants in different populations suggests that individuals with early-onset clinical disease may be the tip of the iceberg of a much larger number of asymptomatic carriers. Alternatively, reproductive fitness could even be slightly increased in some variant carriers to compensate for the reduction of fitness in the more severely affected ones, but this remains to be investigated.

A Novel Homozygous Variant in the COMP Gene Causing a Multiple Epiphyseal Dysplasia 1 with Autosomal Recessive Inheritance

Multiple epiphyseal dysplasia type 1 is one of the most common autosomal dominant types of the genetically heterogeneous group of skeletal dysplasias characterized by impaired ossification of the epiphyses of long bones. To date, it is known that the disease is caused by heterozygous variants in the COMP gene and is characterized by a significant variability in the clinical manifestations. We report the first case of a patient with MED 1 caused by novel homozygous single nucleotide variant c.2170dupG (p.Val724Glyfs*20) in the COMP gene identified by whole-exome sequencing. The following segregation analysis in the family found a detected variant in heterozygous state in healthy consanguineous parents of the proband. Clinical and radiological examination revealed the atypical signs of epiphyseal dysplasia including limited range of extension and supination of both forearms, severe bilateral ulnar clubhand, plano-valgus deformity of the feet and generalized muscle weakness with gait disturbances. Among the clinical features, myopathic signs were the most prominent. The radiological and neurophysiological data can be helpful in the differential diagnostics with the congenital myopathies. The novel homozygous variant in the COMP gene that caused multiple epiphyseal dysplasia 1 with autosomal recessive inheritance can contribute to the more detailed description of genotype–phenotype correlations, which will allow research to understand better the role of the C-terminal domain of COMP.

Pseudoachondroplasia: Phenotype and genotype in 11 Indian patients.

Pseudoachondroplasia (PSACH) is an autosomal dominant disorder characterized by rhizomelic short-limbed skeletal dysplasia. The primary clinical and radiographic features include disproportionate dwarfism, joint laxity and hyperextensibility, exaggerated lumbar lordosis, and late ossification of the epiphyses. Identification of disease-causing variants in heterozygous state in COMP establishes the molecular diagnosis of PSACH. We examined 11 families with clinical features suggestive of PSACH. In nine families, we used Sanger sequencing of exons 8-19 of COMP (NM_000095.2) and in two families exome sequencing was used for confirming the diagnosis. We identified 10 de novo variants, including five known variants (c.925G>A, c.976G>A, c.1201G>T, c.1417_1419del, and c.1511G>A) and five variants (c.874T>C, c.1201G>C, c.1309G>A, c.1416_1421delCGACAA, and c.1445A>T) which are not reported outside Indian ethnicity. We hereby report the largest series of individuals with molecular diagnosis of PSACH from India and reiterate the well-known genotype-phenotype corelation in PSACH.

Identification of a novel variant in GPR56/ADGRG1 gene through whole exome sequencing in a consanguineous Pakistani family

GPR56 gene is best known for its pivotal role in cerebral cortical development. Mutations inGPR56give rise to cobblestone-like brain malformation, white matter changes and cerebellar dysplasia. This study aimed to identify causative variant in a consanguineous family having five individuals affected with developmental delay, mild to severe intellectual disability, speech impairment, strabismus and seizures. Whole exome sequencing was performed to identify mutation in affected individuals. Variants were filtered and further validated by Sanger sequencing and segregation analysis. A novel frameshift variant c.1601dupT leading to p.Ala535GlyfsTer17) was identified in GPR56 gene by whole exome sequencing and subsequent filtering. All five affected individuals were homozygous for the mutant allele while four asymptomatic individuals carried the variant in heterozygous state. Radiological findings of a representative patient presented features of GPR56-associated cobblestone like brain malformation. MRI findings suggested paucity of sulci, dilated ventricular system and brainstem atrophy. The microgyria were observed in a simplified gyral pattern (cobblestone). This single bp insertion, and the consequent frameshift, results in the truncation of GPR56 protein. This could result in a malformed cortex giving the brain a cobblestone like shape. Our study identified a 7th novel frameshift variant from Pakistani population in GPR56 gene, thus broadening mutation spectrum.

Genetics of Hearing Impairment in North-Eastern Romania-A Cost-Effective Improved Diagnosis and Literature Review.

Background: We have investigated the main genetic causes for non-syndromic hearing impairment (NSHI) in the hearing impairment individuals from the North-Eastern Romania and proposed a cost-effective diagnosis protocol. Methods: MLPA followed by Sanger Sequencing were used for all 291 patients included in this study. Results: MLPA revealed abnormal results in 141 cases (48.45%): 57 (40.5%) were c.35delG homozygous, 26 (18.44%) were c.35delG heterozygous, 14 (9.93%) were compound heterozygous and 16 (11.35%) had other types of variants. The entire coding region of GJB2 was sequenced and out of 150 patients with normal results at MLPA, 29.33% had abnormal results: variants in heterozygous state: c.71G>A (28%), c.457G>A (20%), c.269T>C (12%), c.109G>A (12%), c.100A>T (12%), c.551G>C (8%). Out of 26 patients with c.35delG in heterozygous state, 38.46% were in fact compound heterozygous. Conclusions: We identified two variants: c.109G>A and c.100A>T that have not been reported in any study from Romania. MLPA is an inexpensive, rapid and reliable technique that could be a cost-effective diagnosis method, useful for patients with hearing impairment. It can be adaptable for the mutation spectrum in every population and followed by Sanger sequencing can provide a genetic diagnosis for patients with different degrees of hearing impairment.

X Chromosome inactivation: a modifier of factor VIII and IX plasma levels and bleeding phenotype in Haemophilia carriers.

Haemophilia A and B are X-linked hemorrhagic disorders caused by gene variants in the F8 and F9 genes. Due to recessive inheritance, males are affected, while female carriers are usually asymptomatic with a wide range of factor VIII (FVIII) or IX (FIX) levels. Bleeding tendency in female carriers is extremely variable and may be associated with low clotting factor levels. This could be explained by F8 or F9 genetic variations, numerical or structural X chromosomal anomalies, or epigenetic variations such as irregular X chromosome inactivation (XCI). The aim of the study was to determine whether low FVIII or FIX coagulant activity in haemophilia carriers could be related to XCI and bleeding symptoms. HUMARA assay was performed on 73 symptomatic carriers with low clotting activity ≤50 IU/dL. Bleeding Assessment Tool (BAT) from the International Society on Thrombosis and Haemostasis (ISTH) was used to describe symptoms in the cohort of carriers. In 97% of haemophilia carriers, a specific gene variant in heterozygous state was found, which alone could not justify their low FVIII or FIX levels (≤50 IU/dL). A statistical association between XCI pattern and FVIII and FIX levels was observed. Moreover, female carriers with low coagulant activity (≤20 IU/dL) and high degree of XCI ( ≥ 80:20) had a higher ISTH-BAT score than the carriers with the opposite conditions (>20 IU/dL and <80:20). In our cohort of haemophilia carriers, XCI was significantly skewed, which may contribute to the low expression of clotting factor levels and bleeding symptoms.

SAT-093 Two Cases of Autosomal Dominant Familial Central Diabetes Insipidus: A Novel Variant in Neurophysin II Region of AVP Gene

Central diabetes insipidus (CDI) is a disorder of water balance characterized by polyuria and polydipsia owing to partial or complete deficiency of the antidiuretic hormone, arginine vasopressin (AVP). Although non-hereditary causes are the most frequent, Familial CDI forms, due to heterozygous mutations in the AVP gene, have also long been recognized. Inheritance occurs mostly in an autosomal dominant manner with almost complete penetrance. The AVP gene encodes for a 164 aminoacids preprotein: the AVP preprohormone which consists of a signal peptide, AVP hormone (9 amino acidpeptide), Neurophysin II (AVP carrier), and a glycoprotein, Copeptin. The AVP preprohormone, is produced in the hypothalamus sand is targeted to the endoplasmic reticulum (ER) by the signal peptide. After cleavage and processing, the AVP hormone is packaged within protein carrier NPII and are transported by axonal trafficking to the neurohypophysis where they can be stored and secreted.Structural changes in NPII have been associated with intracellular accumulation of mutant AVP precursors that have been postulated to be cytotoxic and decreased cell viability of vasopressin-producing neuronsin the neurohypophysis.In this study we describe two index cases from two families of four-generation kindred suspected to have Familial neurohypophyseal diabetes insipidus (FNDI), with absent or barely visibleposterior pituitary by MRI. A water deprivation test was performed in both cases, resulting confirmatory for DI in case 1 while it was inconclusive in case 2.In both cases, molecular studies revealed a pathogenic variant in heterozygous state in the NPII region of the AVP gene, in case 1 we found a previously reported and well characterized variant p.Cys116Gly, cysteine at codon 116 is involved in disulfide bridge important for the secondary structure of NPII. While in case 2 we found a novel variant, p.Gly45Val, in which all in silico tools predict deletereous, whereas there are a previously reported patogenic variant at the same amino acid residueand in 3D modeling it can be observed that structural and conformational changes occur in binding bridge of NPII.We are reporting two novel non related familial CDI cases, even though lack of functional studies, the clinical phenotype in each pedigree suggest this diagnosis, and support the genetic counseling.

Novel Missense Variant in Heterozygous State in the BRPF1 Gene Leading to Intellectual Developmental Disorder With Dysmorphic Facies and Ptosis

Intellectual developmental disorder with dysmorphic facies and ptosis is an autosomal dominant condition characterized by delayed psychomotor development, intellectual disability, delayed speech, and dysmorphic facial features, mostly ptosis. Heterozygous mutations in bromodomain and plant homeodomain (PHD) finger containing one (BRPF1) gene have been reported. In this study, whole exome sequencing (WES) was performed as a molecular diagnostic test. Bioinformatics of WES data and candidate gene prioritization identified a novel variant in heterozygous state in the exon 3 of BRPF1 gene (ENST383829: c.1054G > C and p.Val352Leu). Autosomal dominant inheritance in the family affected individuals and exclusion of non-pathogenicity in the ethnically matched healthy controls (n = 100) were performed by Sanger sequencing. To the best of our knowledge, this is the first evidence of BRPF1 variant in a Saudi family. Whole exome sequencing analysis has been proven as a valuable tool in the molecular diagnostics. Our findings further expand the role of WES in efficient disease diagnosis in Arab families and explained that the mutation in BRPF1 gene plays an important role for the development of IDDFP syndrome.

Whole exome sequencing establishes diagnosis of Charcot–Marie–Tooth 4J, 1C, and X1 subtypes

BackgroundCharcot–Marie–Tooth (CMT) hereditary polyneuropathies pose a diagnostic challenge. Our aim here is to describe CMT patients diagnosed by whole exome sequencing (WES) following years of fruitless testing.Methods/ResultsThree patients with polyneuropathy suspected to be genetic in origin, but not harboring PMP22 gene deletion/duplication, were offered WES. The first patient, a 66‐year‐old man, had been suffering from progressive weakness and atrophies in the lower and upper extremities for 20 years. Due to ambiguous electrophysiological findings, immune therapies were administered to no avail. Twelve years after PMP22 deletion/duplication testing, WES revealed two pathogenic variants in the FIG4 gene (p.Ile41Thr and p.Phe598fs, respectively), as a cause of CMT 4J. The second patient, a 19‐year‐old man, had been suffering from hearing and gait impairment since at least his infancy, and recently presented with weakness and dystonia of the lower extremities. In this patient, WES identified the p.Leu122Val LITAF gene variant in heterozygous state, suggesting the diagnosis of CMT 1C, several years after initial genetic analyses. The third patient, a 44‐year‐old man, presented with progressive weakness and atrophies of the lower and upper extremities since the age of 17 years old. In this patient, WES identified the hemizygous p.Arg164Gln pathogenic variant in the GJB1 gene, establishing the diagnosis of CMT X1, 8 years after testing for PMP22 deletion/duplication.ConclusionNovel diagnostic techniques, such as WES, offer the possibility to decipher the cause of CMT subtypes, ending the diagnostic Odyssey of the patients and sparing them from unnecessary and potentially harmful treatments.

Cryopyrin-Associated Periodic Syndrome (CAPS) Caused by c.943A&gt;G Variant of NLRP3 Gene: Clinical Case

Background. Cryopyrin-associated periodic syndromes is a g roup of rare congenital autoinflammatory diseases such as familial cold autoinflammatory syndrome, Muckle-Wells syndrome and chronic infantile neurological cutaneous articular syndrome. These syndromes are considered as clinical variants of one disease with different intensity of clinical features and severity of pathologic process. The onset of these syndromes is usually on the first year of life, and they start with fever, urticarial rash, various variants of joint diseases (from arthralgia to residual and persistent arthritis) and nervous system disturbances. There are only single case reports of cryopyrin-associated periodic syndromes in Russia. Clinical Case Description. The disease onset was at the age of 1 year 8 months with fever and rash as well as generalized joint syndrome. Autoinflammatory syndrome was suspected due to to results of blood tests, MRI, molecular genetic testing. Exons 2, 3 and 4 of TNFRSF1A gene and exon 4 of NLRP3 gene with nearby introns were studied with the method of direct automated sequencing. The c.943A&gt;G variant in heterozygous state in NLRP3 gene was revealed. The child was treated with IL-1 beta inhibitor (canakinumab) with positive effect. Conclusion. Diagnostics of cryopyrin-associated periodic syndrome in children is the serious challenge. Timely decision with help of molecular genetic methods is crucial for successful target therapy.

Rare single-nucleotide variants in oculo-auriculo-vertebral spectrum (OAVS).

BackgroundOculo‐auriculo‐vertebral spectrum (OAVS) is a craniofacial developmental disorder that affects structures derived from the first and second pharyngeal arches. The clinically heterogeneous phenotype involves mandibular, oral, and ear development anomalies. Etiology is complex and poorly understood. Genetic factors have been associated, evidenced by chromosomal abnormalities affecting different genomic regions and genes. However, known pathogenic single‐nucleotide variants (SNVs) have only been identified in MYT1 in a restricted number of patients. Therefore, investigations of SNVs on candidate genes may reveal other pathogenic mechanisms. MethodsIn a cohort of 73 patients, coding and untranslated regions (UTR) of 10 candidate genes (CRKL, YPEL1, MAPK1, NKX3‐2, HMX1, MYT1, OTX2, GSC, PUF60, HOXA2) were sequenced. Rare SNVs were selected and in silico predictions were performed to ascertain pathogenicity. Likely pathogenic variants were validated by Sanger sequencing and heritability was assessed when possible.ResultsFour likely pathogenic variants in heterozygous state were identified in different patients. Two SNVs were located in the 5’UTR of YPEL1; one in the 3’UTR of CRKL and one in the 3’UTR of OTX2.ConclusionOur work described variants in candidate genes for OAVS and supported the genetic heterogeneity of the spectrum.

Genetic Study of Hepatocyte Nuclear Factor 1 Alpha Variants in Development of Early-Onset Diabetes Type 2 and Maturity-Onset Diabetes of the Young 3 in Iran.

Background:Maturity-onset diabetes of the young (MODY) is a clinically and genetically heterogeneous group of diabetes characterized by noninsulin-dependent, autosomal-dominant disorder with strong familial history, early age of onset, and pancreatic beta-cell dysfunction. Mutations in at least 14 different genes are responsible for various MODY subtypes. Heterozygous mutations in the hepatocyte nuclear factor 1 alpha (HNF1A) gene are responsible for the MODY3 subtype, which is a common subtype of MODY in different studied populations. To date, more than 450 different variants of this gene have been reported as disease causing for MODY3. This study was carried out to evaluate HNF1A mutations in Iranian diabetic families fulfilling MODY criteria.Materials and Methods:Polymerase chain reaction and Sanger sequencing were performed. All the ten exons of the HNF1A gene were sequenced in ten families, followed by cosegregation analysis and in silico evaluation. Computational protein modeling was accomplished for the identified mutation.Results:MODY3 was confirmed in two large families by detecting a mutation (p.G253E) in coding regions of HNF1A. Compound heterozygous state for two common variants in HNF1A (p.I27 L and p.S487N) was detected in affected members of 5 families, and in one family, a rare benign variant in the coding sequence for Kozak sequence was detected. Two new nonpathogenic variants were found in noncoding regions of HNF1A.Conclusion:It seems that HNF1A mutations are a common cause of MODY in Iranian diabetic patients. Identified common variants in heterozygous state can cause diabetes Type II in earlier ages. The role of rare variant rs3455720 is unknown, and more investigation is needed to uncover the function of this variant.

Поиск и классификация генетических вариантов в генах фосфорилазкиназного комплекса у группы пациентов с подозрением на наследственные нарушения метаболизма гликогена

Glycogen storage diseases (GSD) are a heterogeneous group of inherited defects of metabolism of glycogen. GSD du to phosphorylase kinase (PhK) deficiency named GSD IX is the most common of them. It belongs to liver GSDs and occurs in several subtypes that differ in mode of inheritance and tissue-specificity. PhK consists of several subunits coding by different genes. The genes PHKA2, PHKB and PHKG2 make the main contribution to GSD IX etiology. The aim of this study is analysis of genetic specify and genotype-phenotype correlations in patients with mutations in genes of PhK complex. 36 children with liver pathology from 30 unrelated families were studied. Using massively parallel sequencing technology 47 target genes with mutations resulted in liver pathology were analyzed in patients. In 28 patients 18 different hemizygous mutant alleles of PHKA2 were found. In 4 patients 5 homozygous or compound-heterozygous mutations of PHKG2 were detected. 14 PHKA2 variants and 3 PHKG2 variantss are novel. Heterozygous mutations of PHKB and PHKG2 were found in 3 and 1 pts respectively. Clinical significance of some variants in PHKA2, PHKB and PHKG2 is unclear. Most of detected mutations are missense-mutations. There are a few unclear cases with unreliable missense variants and variants in heterozygous state combined with ambiguous clinical features. The analysis of determined novel mutations and its possible effects on PhK complex shows that the finding of a rare variant is not ample for the diagnosis. Diagnosis confirmation must be based on complex study of all available data of frequencies, homology, gene structure and enzyme activity and combine analysis of genetic, clinical and laboratory features and signs.

Santos syndrome is caused by mutation in the WNT7A gene.

We have recently described a family with a condition (Santos syndrome (SS; MIM 613005)) characterized by fibular agenesis/hypoplasia, hypoplastic femora and grossly malformed/deformed clubfeet with severe oligodactyly, ungual hypoplasia/anonychia, sometimes associated with mild brachydactyly and occasional pre-axial polydactyly. Autosomal dominant inheritance with incomplete penetrance was suggested, but autosomal recessive inheritance could not be ruled out, due to the high frequency of consanguineous matings in the region where the family lived. This report deals with linkage studies and exome sequencing, disclosing a novel variant in WNT7A, c.934G>A (p.Gly312Ser), as the cause of this syndrome. This variant was present in homozygous state in five individuals typically affected by the SS syndrome, and in heterozygous state in the son of one affected homozygous individual. The heterozygous boy presented only unilateral complex polysyndactyly and we hypothesize that he either presents a distinct defect or that his phenotype results from a rare, mild clinical manifestation of the variant in heterozygous state. Variants in WNT7A are known to cause at least two other limb defect disorders, the syndromes of Fuhrmann and Al-Awadi/Raas-Rothschild. Despite their variable degree of expressivity and overlap, the three related conditions can be differentiated phenotypically in most instances.

Familial Hemiplegic Migraine with Severe Attacks: A New Report with ATP1A2 Mutation.

Introduction. Familial hemiplegic migraine (FHM) is a rare disorder characterized by migraine attacks with motor weakness during the aura phase. Mutations in CACNA1A, ATP1A2, SCN1A, and PRRT2 genes have been described. Methods. To describe a mutation in ATP1A2 gene in a FHM case with especially severe and prolonged symptomatology. Results. 22-year-old woman was admitted due to migraine-type headache and sudden onset of right-sided weakness and aphasia; she had similar episodes in her childhood. Her mother was diagnosed with hemiplegic migraine without genetic confirmation. She presented with fever, decreased consciousness, left gaze preference, mixed aphasia, right facial palsy, right hemiplegia, and left crural paresis. Computed tomography (CT) showed no lesion and CT perfusion study evidenced oligohemia in left hemisphere. A normal brain magnetic resonance (MR) was obtained. Impaired consciousness and dysphasia began to improve three days after admission and mild dysphasia and right hemiparesis lasted for 10 days. No recurrences were reported during a follow-up of two years. We identified a variant in heterozygous state in ATP1A2 gene (p.Thr364Met), pathogenic according to different prediction algorithms (SIFT, PolyPhen2, MutationTaster, and Condel). Conclusion. Prolonged and severe attacks with diffuse hypoperfusion in a FHM seemed to be specially related to ATP1A2 mutations, and p.T364M should be considered.

Congenital macrothrombocytopenia associated with a combination of functional polymorphisms in the TUBB1 gene

Congenital thrombocytopenia in childhood and adolescence requires an extensive diagnostic workup to find the underlying reason. We report on a 13-year-old female patient who was incidentally found to have moderate thrombocytopenia which was also diagnosed in her father and brother. Within the microscopic evaluation of a peripheral blood smear macrothrombocytes were found. Immunofluorescence microscopy of the patient's platelets detected the lack of β1-tubulin. Analysis of the TUBB1 gene revealed three known missense variants in heterozygous state which in combination might explain the β1-tubulin defect.

The -13914G>A variant upstream of the lactase gene (LCT) is associated with lactase persistence/non-persistence

Background. Adult-type hypolactasia (lactase non-persistence) is a common cause of gastrointestinal symptoms. Several DNA sequence variants have been identified for the lactase-persistence/non-persistence (LP/LNP), the most common being the C to T residing -13910 bp upstream of the lactase gene (LCT). We have analysed sequence variants of LP/LNP in subjects originating from Northern Russia. Methods. A total of 148 subjects with gastrointestinal complaints were genotyped covering about 400 bp around the -13910C/T variant using direct PCR-sequencing. All patients were interviewed about milk-related symptoms using the questionnaire. Disaccharidase activities were measured from intestinal biopsy specimens of the index person. Results. The prevalence of the -13910C/C genotype among 148 patients was 28.4%. A G to A variant residing 13914 bp upstream from the LCT gene (-13914G>A) was identified in one participant carrying the -13910C/C genotype. In two biopsy specimens her lactase activity was above the generally accepted cut off level for adult-type hypolactasia, 10U/g protein. Three other family members also carried the -13914G>A genotype. Among eight family members five had the LNP genotype -13910C/C. Conclusion. A rare variant G to A residing 13914 bp upstream of the LCT gene was identified in a subject carrying the more frequent variant -13910C/C. The -13914G>A variant in heterozygous state was associated with increased lactase activity, suggesting that the increased lactase activity is most likely to be associated with the -13914G>A variant. Further studies need to be done to confirm the functional role of this variant.