Whole-Exome Sequencing Identified Two Novel Pathogenic Mutations in the PTCH1 Gene in BCNS.

Basal cell nevus syndrome (BCNS, OMIM 109400) is a familial cancer syndrome characterized by the development of numerous basal cell cancers and various other developmental abnormalities, including epidermal cysts of the skin, calcified dural folds, keratocysts of the jaw, palmar and plantar pits, ovarian fibromas, medulloblastomas, lymphomesenteric cysts, and fetal rhabdomyomas. BCNS shows autosomal dominant inheritance and is caused by mutations in the patched 1 (PTCH1) gene and the suppressor of the fused homolog (SUFU) gene. In a few cases, variants of patched 2 (PTCH2) have been found in patients who met the criteria for BCNS. In an investigation of 11 Hungarian families who fulfilled the diagnostic criteria for BCNS, whole-exome sequencing (WES) and multiplex ligation-dependent probe amplification (MLPA) identified two novel pathogenic variants (c.2994C>A; p.Cys998Ter and c.814_818del; p.Asn272SerfsTer11), one recently identified variant (c.1737_1745del p.Val580_Val582del), and three recurrent disease-causing variants of the PTCH1 gene with a diagnosis rate of 63.6%. Disease-causing variants were not found for the SUFU and PTCH2 genes. These applied methods could not fully elucidate the genetic background of all the BCNS cases that we investigated. To uncover the missing heritability of BCNS, whole-genome sequencing or an epigenetic approach might be considered in the future.

Whole Exome Sequencing in a Series of Patients with a Clinical Diagnosis of Tuberous Sclerosis Not Confirmed by Targeted TSC1/TSC2 Sequencing.

BACKGROUND: Approximately fifteen percent of patients with tuberous sclerosis complex (TSC) phenotype do not have any genetic disease-causing mutations which could be responsible for the development of TSC. The lack of a proper diagnosis significantly affects the quality of life for these patients and their families. METHODS: The aim of our study was to use Whole Exome Sequencing (WES) in order to identify the genes responsible for the phenotype of nine patients with clinical signs of TSC, but without confirmed tuberous sclerosis complex 1/ tuberous sclerosis complex 2 (TSC1/TSC2) mutations using routine molecular genetic diagnostic tools. RESULTS: We found previously overlooked heterozygous nonsense mutations in TSC1, and a heterozygous intronic variant in TSC2. In one patient, two heterozygous missense variants were found in polycystic kidney and hepatic disease 1 (PKHD1), confirming polycystic kidney disease type 4. A heterozygous missense mutation in solute carrier family 12 member 5 (SLC12A5) was found in one patient, which is linked to cause susceptibility to idiopathic generalized epilepsy type 14. Heterozygous nonsense variant ring finger protein 213 (RNF213) was identified in one patient, which is associated with susceptibility to Moyamoya disease type 2. In the remaining three patients WES could not reveal any variants clinically relevant to the described phenotypes. CONCLUSION: Patients without appropriate diagnosis due to the lack of sensitivity of the currently used routine diagnostic methods can significantly profit from the wider application of next generation sequencing technologies in order to identify genes and variants responsible for their symptoms.

Hereditary and non-hereditary etiologies associated with extensive brain calcification: case series.

Cerebral calcification may be caused by several potentially treatable conditions, however, in most cases it does not receive special attention in clinical practice. From the point of view of etiology, the diseases associated with cerebral calcification can be divided into two main groups: idiopathic (mostly incurable) and secondary (potentially treatable). The first group includes mainly the hereditary diseases identified before 2021 (primary familial brain calcification subtypes, previously known as Fahr's disease or Fahr's syndrome). In contrast, the second group includes diseases with cerebral calcification that develop generally as a consequence of metabolic/endocrine/autoimmune abnormalities. The aim of our research was to present hereditary and non-hereditary etiologies associated with extensive brain calcification. We compare the detailed clinical, radiological and laboratory results of 6 patients with prominent cerebral calcification identified in our clinic in the last 3 years (idiopathic and secondary etiologies as well). Our research draws attention to the complexity of the etiologies in the context of cerebral calcification. We recommend, beside NGS-based sequence analyses, the application of array comparative genomic hybridization as well, to identify potential genetic etiologies associated with brain calcification.

[Zonisamide treatment in myoclonus-dystonia]. / Zonisamidkezelés myoclonusdystoniában.

Myoclonus-dystonia (DYT11) is a rare, autosomal dominant hereditary disorder clinically characterized by myoclonus and/or dystonia. The disease is most commonly caused by the mutations of the SGCE gene. Causative therapy is not available currently. Regarding symptomatic treatment, zonisamide, insulin therapy, carbamazepine and zolpidem may be utilized. If these drugs are not effective, bilateral globus pallidus internus deep brain stimulation may come into consideration. The aim of this study is to demonstrate the efficacy of zonisamide treatment in a Hungarian patient with genetically proven myoclonus-dystonia. Our 25-year-old female patient has had jerky, lightning-like movements since her childhood, mainly localized to her right upper limb. In addition, muscle cramps associated with writing and walking were also present. The symptoms were reduced by alcohol consumption. Brain MRI did not show any abnormality. Neurophysiological studies raised the possibility of subcortical myoclonus. After detailed phenotyping, genetic testing was performed, yielding the diagnosis of myoclonus-dystonia. A heterozygous mutation in the 6th exon of the SGCE gene at the position 709, resulting in an early stop codon (c.709C> T, p.Arg237*) was demonstrated. After considering the risk-benefit ratio, we decided to start zonisamide treatment. The dose was titrated gradually to 300 mg/d over 6 weeks. Myoclonus- and dystonia-specific tests demonstrated significant improvement compared to the pre-treatment status. The aim of this case report is to draw attention to this rare condition, its treatment and the importance of collaboration between medical subspecialties. Orv Hetil. 2019; 160(34): 1353-1357.

[Multiple ischemic stroke in Osler-Rendu-Weber disease]. / Multiplex ischaemiás stroke Osler-Rendu-Weber-kórban.

Hereditary hemorrhagic teleangiectasia (HHT, Osler-Rendu-Weber disease) is an autosomal dominantly inherited disorder caused by the mutation of several possible genes and characterized by malformations of the arteriovenous system in multiple organs. The clinical diagnosis is based on the Curaçao criteria ((1) spontaneous, recurrent epistaxis; (2) teleangiectasias in characteristic sites (lips, oral cavity, nose, fingers); (3) visceral lesions (gastrointestinal, pulmonary, cerebral, spinal); (4) affected first degree relative). The aim of this study is to present the first genetically confirmed Hungarian case of hereditary hemorrhagic teleangiectasia with multiple ischemic strokes. Our 70-year-old woman has been suffering from severe epistaxis since her childhood and presented gastrointestinal bleeding during her adulthood as well. The characteristic skin lesions developed in the 5th decade of life. She was admitted to our department with loss of consciousness and fluctuating speech and swallowing problems. MRI of the brain supplemented with angiography revealed multiple arteriovenous malformations and multiple subacute ischemic lesions. The EEG demonstrated slowing of electric activity in the left frontal lobe. The neuropsychological assessment showed deficits in anterograde memory and executive functions. The diagnostic work-up for other characteristic alterations identified an arteriovenous malformation in the left lung. The genetic analysis demonstrated a heterozygous mutation in the 7th exon of the ENG gene at position 834 resulting in a thymine duplication and an early stop codon by a frame shift. The present case is largely similar to those already described in literature and draws the attention to the importance of multidisciplinary collaboration in the care of HHT patients.

Genetic investigation confirmed the clinical phenotype of congenital chloride diarrhea in a Hungarian patient: a case report.

BACKGROUND: Congenital chloride diarrhea (CCD, OMIM 214700) is a rare autosomal recessively inherited condition characterized by watery diarrhea, hypochloremia and metabolic alkalosis. Mutations of the solute carrier family 26, member 3 (SLC26A3, OMIM 126650) gene are responsible for the disease. The gene encodes a transmembrane protein, which is essential for intestinal chloride absorption. CASE PRESENTATION: Here we report a Hungarian boy, presenting the clinical phenotype of CCD. The patient born at 32 weeks of gestation and underwent surgery for abdominal distension and intestinal obstruction related to malrotation. After recovery, electrolyte replacement therapy was necessary due to several periods of diarrhea. After exclusion of other possible causes, increased chloride concentration in the feces supported the diagnosis of CCD. The diagnosis was confirmed by molecular genetic testing. Direct sequencing revealed compound-heterozygosity for a frameshift mutation c.1295delT (p.Leu432Argfs*11) and the known Polish founder mutation c.2024_2026dupTCA (p.Ile675_Arg676insLeu). CONCLUSIONS: Here we present the clinical symptoms of the first patient in Hungary diagnosed with CCD. Based on the clinical symptoms, stool analysis and genetic testing, the diagnosis of CCD was established. Our study provides expansion for the mutation spectrum of the SLC26A3 gene and the genetic background of CCD.

Somatic mosaicism of the PIK3CA gene identified in a Hungarian girl with macrodactyly and syndactyly.

Isolated macrodactyly (OMIM 155500) belongs to a heterogeneous group of overgrowth syndromes. It is a congenital anomaly resulting in enlargement of all tissues localized to the terminal portions of a limb and caused by somatic mutations in the phosphatidylinositol 3-kinase catalytic alpha (PIK3CA, OMIM 171834) gene. Here we report a Hungarian girl with macrodactyly and syndactyly. Genetic screening at hotspots in the PIK3CA gene identified a mosaic mutation (c.1624G > A, p.Glu542Lys) in the affected tissue, but not in the peripheral blood. To date, this somatic mutation has been reported in eight patients affected by different forms of segmental overgrowth syndromes. Detailed analysis of the Hungarian child and previously reported cases suggests high phenotypic diversity associated with the p.Glu542Lys somatic mutation. The identification of the mutation provides a novel therapeutic modality for the affected patients: those who carry somatic mutations in the PIK3CA gene are potential recipients of a novel "repurposing" approach of rapamycin treatment.

Nemaline myopathy type 2 (NEM2): two novel mutations in the nebulin (NEB) gene.

Nemaline myopathy is a type of the heterogeneous group of congenital myopathies. Generalized hypotonia, weakness, and delayed motor development are the main clinical features of the typical congenital form. Histopathology shows characteristic nemaline rods in the muscle biopsy. Mutations in at least 7 genes, including nebulin gene (NEB), proved to be responsible for this muscle disease. We present a boy with nemaline myopathy type 2 (NEM2) caused by compound heterozygosity for 2 novel mutations, a deletion and a duplication in the NEB gene. The deletion was inherited from the father and the duplication from the mother. Testing all family members supports genetic counseling.

[Difficulties of genetic counselling in rare, mainly neurogenetic disorders]. / Genetikai tanácsadási nehézségek ritka, foként neurogenetikai kórképekben.

INTRODUCTION: In recent decades methods used for the investigation of the genetic background of rare diseases showed a great improvement. AIM: The aim of the authors was to demonstrate difficulties of genetic counselling and investigations in case of five rare, mainly neurogenetic diseases. METHOD: During pre-test genetic counselling, the disease suspected from the clinical symptoms and the available genetic tests were considered. During post-test genetic counselling, the results of the genetic tests were discussed. RESULTS: In three of the five cases genetic tests identified the disease-causing genetic abnormalities, while in two cases the causative abnormalities were not identified. CONCLUSIONS: Despite a great improvement of the available genetic methods, the causative genetic abnormalities cannot be identified in some cases. The genetic counsellor has a key role in the assessment and interpretation of the results and in helping the family planning.

Identification of a novel missense GLRA1 gene mutation in hyperekplexia: a case report.

INTRODUCTION: Hereditary hyperekplexia is a neurological disorder characterized by excessive startle responses with violent jerking to noise or touch, stiffening of the trunk and limbs, clenching of the fists and attacks of a high-frequency trembling. Hyperekplexia has a heterogeneous genetic background with several identified causative genes and demonstrates both dominant and recessive inheritance. Mutations in the glycine receptor alpha 1 subunit gene occur in about 30 percent of hyperekplexia cases. CASE PRESENTATION: In this study, we report the case of a Hungarian boy whose abnormal movements, muscle stiffness and convulsions were first noted when he was 4 days old. Neurological and electrophysiological investigation suggested the clinical diagnosis of hyperekplexia. CONCLUSIONS: Direct sequencing of the coding regions and the flanking introns of the glycine receptor alpha 1 subunit gene revealed a novel heterozygous missense mutation (c.211A/T, p.Ile71Phe). Genetic screening of our patient's family revealed that the clinically unaffected parents and sister do not carry the mutation, suggesting that the identified sequence change is a de novo mutation. Since hyperekplexia can have severe consequences, including sudden infant death due to laryngospasm and cardiorespiratory failure, identification of the causative genetic alteration(s) of the disease is high priority. Such knowledge is necessary for prenatal diagnosis, which would allow informed family planning and greater parental sensitivity to hyperekplexia 1-associated risks.

Nasal bone length: prenasal thickness ratio: a strong 2D ultrasound marker for Down syndrome.

OBJECTIVES: To evaluate the feasibility of incorporating two-dimensional ultrasound measurements of nasal bone length (NBL) and prenasal thickness (PT) into the second-trimester anomaly scan and to determine whether the NBL : PT ratio could help in differentiating euploid and Down syndrome fetuses. METHOD: Two-dimensional measurements of NBL and PT were obtained from the midsagittal plane of the fetal head at 14-28 weeks of gestation in a Caucasian population at risk for aneuploidy. The screening performances of NBL, PT, and the ratios NBL : PT and PT : NBL were analyzed in euploid (n = 1330) and Down syndrome (n = 33) fetuses. RESULTS: Nasal bone length and PT alone showed strong correlations with Down syndrome (sensitivity: 76% at 1.88% and 2.35% false positive rate, respectively). However, the NBL : PT ratio showed an even stronger correlation with Down syndrome (false positive rate: 0.9%, sensitivity: 97%). The mean NBL : PT ratio showed a gradual increase from 1.48 to 1.79 (a 21.2% increase) between 14 and 28 weeks of gestation. CONCLUSION: Two-dimensional ultrasound measurements of NBL and PT, particularly the NBL : PT ratio, are highly sensitive markers for Down syndrome fetuses.

Early detection of Angelman syndrome resulting from de novo paternal isodisomic 15q UPD and review of comparable cases.

BACKGROUND: Angelman syndrome is a rare neurogenetic disorder that results in intellectual and developmental disturbances, seizures, jerky movements and frequent smiling. Angelman syndrome is caused by two genetic disturbances: either genes on the maternally inherited chromosome 15 are deleted or inactivated or two paternal copies of the corresponding genes are inherited (paternal uniparental disomy). A 16-month-old child was referred with minor facial anomalies, neurodevelopmental delay and speech impairment. The clinical symptoms suggested angelman syndrome. The aim of our study was to elucidate the genetic background of this case. RESULTS: This study reports the earliest diagnosed angelman syndrome in a 16-month-old Hungarian child. Cytogenetic results suggested a de novo Robertsonian-like translocation involving both q arms of chromosome 15: 45,XY,der(15;15)(q10;q10). Molecular genetic studies with polymorphic short tandem repeat markers of the fibrillin-1 gene, located in the 15q21.1, revealed that both arms of the translocated chromosome were derived from a single paternal chromosome 15 (isodisomy) and led to the diagnosis of angelman syndrome caused by paternal uniparental disomy. CONCLUSIONS: AS resulting from paternal uniparental disomy caused by de novo balanced translocation t(15q;15q) of a single paternal chromosome has been reported by other groups. This paper reviews 19 previously published comparable cases of the literature. Our paper contributes to the deeper understanding of the phenotype-genotype correlation in angelman syndrome for non-deletion subclasses and suggests that patients with uniparental disomy have milder symptoms and higher BMI than the ones with other underlying genetic abnormalities.

Role of the vascular endothelial growth factor in the inverse relationship between increased nuchal translucency thickness and fetomaternal transfusion.

OBJECTIVE: To elucidate the possible etiological role of the vascular endothelial growth factor (VEGF) in the inverse correlation between nuchal translucency (NT) thickness and fetomaternal transfusion (FMT). METHODS: The level of FMT was determined prospectively in 80 viable, singleton pregnancies in which 10-14-week ultrasonographic scanning, NT thickness measurement; chorionic villus sampling (CVS) for fetal karyotyping and VEGF concentration determination were performed. The grouping procedures were based either on NT thickness (<2 MoM in Group I, and ≥2 MoM in Group II), or on karyotype (euploid in Group A, and aneuploid in Group B). The level of FMT was determined via maternal serum α-fetoprotein levels before and after CVS. The FMT and the VEGF concentration of the chorionic tissue were analysed in comparisons between Groups I and II, and between Groups "A" and "B". RESULTS: The mean level of FMT after CVS was 72.5±21.3 µL and 19.28±5.4 µL in Groups I (n=44) and II (n=36), respectively (P<0.02). The VEGF concentration of the chorionic tissue in Groups I and II was 40.6±16.7 pg/mg protein and 21.1±6.3 pg/mg protein, respectively (P=0.28). The mean level of FMT was 57.9±15.0 µL and 8.1±3.9 µL in Groups A and B, respectively (P<0.003). The VEGF concentration of the chorionic tissue in Groups A and B was 25.9±10.7 pg/mg protein and 21.3±11.3 pg/mg protein, respectively (P=0.77). CONCLUSION: No difference exists in the VEGF concentration in the aspirated chorionic tissue between Groups I and II and between Groups A and B. A higher level of FMT was observed among the aneuploid pregnancies after CVS than among the euploid cases. Chorionic VEGF does not influence the inverse relationship between the pre-CVS NT thickness and FMT.

Cystic Dilation of the Aqueductus Sylvii in Case of Trisomy 17p11.2-pter with the Deletion of the Terminal Portion of the Chromosome 6.

Since the 1970s, about 30 cases of partial or complete trisomy 17p have been presented in the literature. Partial trisomies of the short arm of chromosome 17 are somewhat more common, but complete trisomy is quite rare. Most of these cases were described in infants and newborns; and to our knowledge only 3 cases of trisomy 17p have been detected intrauterine. Phenotypic features of trisomy 17p in fetuses are intrauterine growth retardation, ventriculomegaly, cleft lip and cleft palate, micrognathia, horseshoe kidneys, single umbilical artery, and congenital heart defects. The sonographic and foetopathologic findings of a pregnancy trisomy 17p11.2-pter with the deletion of the terminal portion of the chromosome 6 due to paternal balanced translocation are described in this case report.

Leiden mutation, bed rest and infection: simultaneous triggers for maternal deep-vein thrombosis and neonatal intracranial hemorrhage?

The possible etiologic roles of infection and bed rest are discussed in connection with a case of maternal homozygous Leiden mutation leading to prematurity, maternal deep-vein thrombosis and neonatal intracranial hemorrhage in a heterozygous premature baby. Maternal bacterial infection and bed rest may trigger deep-vein femoral thrombosis in women with a homozygous Leiden mutation on tocolytic therapy for the treatment of premature labor. The neonate carrying at least one mutated allele of factor V Leiden might be at risk for the development of intracranial hemorrhage.