The clinical and genetic spectrum of autosomal-recessive TOR1A-related disorders.

In the field of rare diseases, progress in molecular diagnostics led to the recognition that variants linked to autosomal-dominant neurodegenerative diseases of later onset can, in the context of biallelic inheritance, cause devastating neurodevelopmental disorders and infantile or childhood-onset neurodegeneration. TOR1A-associated arthrogryposis multiplex congenita 5 (AMC5) is a rare neurodevelopmental disorder arising from biallelic variants in TOR1A, a gene that in the heterozygous state is associated to torsion dystonia-1 (DYT1 or DYT-TOR1A), an early-onset dystonia with reduced penetrance. While 15 individuals with TOR1A-AMC5 have been reported (less than 10 in detail), a systematic investigation of the full disease-associated spectrum has not been conducted. Here, we assess the clinical, radiological and molecular characteristics of 57 individuals from 40 families with biallelic variants in TOR1A. Median age at last follow-up was 3 years (0-24 years). Most individuals presented with severe congenital flexion contractures (95%) and variable developmental delay (79%). Motor symptoms were reported in 79% and included lower limb spasticity and pyramidal signs, as well as gait disturbances. Facial dysmorphism was an integral part of the phenotype, with key features being a broad/full nasal tip, narrowing of the forehead and full cheeks. Analysis of disease-associated manifestations delineated a phenotypic spectrum ranging from normal cognition and mild gait disturbance to congenital arthrogryposis, global developmental delay, intellectual disability, absent speech and inability to walk. In a subset, the presentation was consistent with fetal akinesia deformation sequence with severe intrauterine abnormalities. Survival was 71% with higher mortality in males. Death occurred at a median age of 1.2 months (1 week - 9 years) due to respiratory failure, cardiac arrest, or sepsis. Analysis of brain MRI studies identified non-specific neuroimaging features, including a hypoplastic corpus callosum (72%), foci of signal abnormality in the subcortical and periventricular white matter (55%), diffuse white matter volume loss (45%), mega cisterna magna (36%) and arachnoid cysts (27%). The molecular spectrum included 22 distinct variants, defining a mutational hotspot in the C-terminal domain of the Torsin-1A protein. Genotype-phenotype analysis revealed an association of missense variants in the 3-helix bundle domain to an attenuated phenotype, while missense variants near the Walker A/B motif as well as biallelic truncating variants were linked to early death. In summary, this systematic cross-sectional analysis of a large cohort of individuals with biallelic TOR1A variants across a wide age-range delineates the clinical and genetic spectrum of TOR1A-related autosomal-recessive disease and highlights potential predictors for disease severity and survival

A multi-centre student survey on weighing disciplines in medical curricula - a pilot study

Aim: Initiated by students, this pilot study examines how obtaining medical students' perspectives via a structured online survey may prove useful for curriculum deliberation. Methods: In 2012, 747 students of 32 medical faculties in Germany assessed disciplines specified in the Medical Licensure Act (AApprO) thereby concerning the allocation of teaching time, perceived usefulness regarding preparation for state examination and medical practice, their interest and motivation for studying as well as consideration for future work. Results: Internal medicine, surgery, paediatrics, gynaecology/obstetrics and general medicine rank amongst the upper third regarding allocation of teaching time and perceived usefulness for future medical practice. Concerning both preparation for state examination and medical practice internal medicine ranks second, while surgery only 22nd and 28th of 32, respectively. Some clinical-theoretical disciplines (e.g. pharmacology) are in the top ten regarding perceived preparation for state examination, too. Students who consider choosing internal medicine for future work rate associated disciplines significantly higher regarding usefulness for clinical practice (e.g. pharmacology) or motivation for studying (e.g. microbiology) than other students do. Conclusion: A simple survey reveals interesting data on students' perceptions and ideas of medical studies. Though the data are plausible, interpretations should be done with caution. Nonetheless, data like these should give rise to further questions and discussions, e.g. as part of curriculum deliberation

Deficient body structural description contributes to apraxic end-position errors in imitation

Apraxia is a common cognitive deficit after left hemisphere (LH) stroke. It has been suggested that a disturbed representation of the human body underlies apraxic imitation deficits. Thus, we here tested the hypothesis that a deficient body structural description (BSD), i.e., a deficient representation of a body part's position (relative to a standard human body), contributes to apraxic end-position errors in imitation, while controlling for deficits in the semantic representation of the human body (body image, BI) and naming deficits. A quantitative pointing task to assess putative BSD deficits and an apraxia assessment, including imitation and pantomime tasks, were applied to 27 patients with LH stroke and 19 healthy subjects. While LH stroke patients without apraxia (n = 15) did not differ from control subjects in their pointing performance, patients suffering from imitation apraxia (n = 10) showed a differential deficit when pointing to body parts of other humans compared to object parts. Voxel-based lesion symptom mapping (VLSM) revealed an association of these differential pointing deficits (indicating a deficient BSD) with lesions in the angular gyrus of the left inferior parietal cortex. This first quantitative group study of BSD deficits in LH stroke patients supports the notion that apraxic end-position errors in imitation are - at least in part - due to a deficient coding of the position of human body parts

Novel Genetic and Phenotypic Expansion in Ameliorated <i>PUF60</i>-Related Disorders

Heterozygous variants in the Poly(U) Binding Splicing Factor 60kDa gene (PUF60) have been associated with Verheij syndrome, which has the key features of coloboma, short stature, skeletal abnormalities, developmental delay, palatal abnormalities, and congenital heart and kidney defects. Here, we report five novel patients from unrelated families with PUF60-related disorders exhibiting novel genetic and clinical findings with three truncating variants, one splice-site variant with likely reduced protein expression, and one missense variant. Protein modeling of the patient’s missense variant in the PUF60 AlphaFold structure revealed a loss of polar bonds to the surrounding residues. Neurodevelopmental disorders were present in all patients, with variability in speech, motor, cognitive, social-emotional and behavioral features. Novel phenotypic expansions included movement disorders as well as immunological findings with recurrent respiratory, urinary and ear infections, atopic diseases, and skin abnormalities. We discuss the role of PUF60 in immunity with and without infection based on recent organismic and cellular studies. As our five patients showed less-severe phenotypes than classical Verheij syndrome, particularly with the absence of key features such as coloboma or palatal abnormalities, we propose a reclassification as PUF60-related neurodevelopmental disorders with multi-system involvement. These findings will aid in the genetic counseling of patients and families

Novel mutations in SLC6A5 with benign course in hyperekplexia

Infants suffering from life-threatening apnea, stridor, cyanosis, and increased muscle tone may often be misdiagnosed with infantile seizures and inappropriately treated because of lack and delay in genetic diagnosis. Here, we report a patient with increased muscle tone after birth and hypertonic attacks with life-threatening apnea but no epileptiform patterns in EEG recordings. We identified novel compound heterozygous variants in SLC6A5 (NM_004211.4:c.[1429T> C];[1430delC]) by trio whole-exome sequencing, containing a base deletion inherited by the asymptomatic mother leading to a frameshift (c.1430delC, p.Ser477PhefsTer9) and a de novo base exchange leading to an amino acid change (c.1429T > C, p.Ser477Pro). To date, there are four known disease-associated genes for primary hyperekplexia, all of which are involved in the functioning of glycinergic synapses. SLC6A5 encodes the sodium- and chloride-dependent glycine transporter 2 (GlyT2), which recaptures glycine, a major inhibitory transmitter in the brainstem and spinal cord. The diagnosis altered the patient's medical care to his benefit because SLC6A5 mutations with rather benign courses of hyperekplexia may be spared of needless pharmacotherapy. Symptoms eventually decreased in frequency until about once in 2 mo at 2 yr age. We present the first report of halting hyperekplexia episodes by maternal soothing in multiple instances. We highlight the importance of clarifying the genetic diagnosis by rapid next-generation sequencing techniques in this group of infantile apneic attacks with hyperekplexia due to the broad differential diagnoses

Use of whole exome sequencing in the NICU: Case of an extremely low birth weight infant with syndromic features

Single gene (Mendelian) disorders are one of the leading causes of neonatal morbidity and mortality. However, in the setting of preterm birth phenotypic features of genetic diseases are often undifferentiated and are clinically very difficult to interpret based on the wide range of differential diagnoses. We report an extremely low birth weight infant (ELBW) born prematurely at 23 + 0 gestational weeks after twin pregnancy with a novel clinical manifestation with persistent hyperglycaemia as well as the known manifestations of disease-associated hypokinesia, renal salt wasting, and multifocal atrial tachycardia. The patient died of heart failure on the 72nd day of life. Whole exome sequencing (WES) revealed a previously well established, disease-causing heterozygous likely pathogenic variant in the Harvey rat sarcoma viral oncogene homolog (HRAS)-gene (c.35G > C, p. G12A, rs104894230), which implied the clinical diagnosis of Costello syndrome (CS; OMIM#190020.0004). The twin brother merely had complications related to preterm birth and did not show any CS symptoms. In conclusion, our case illustrated that CS should be considered in ELBW infants showing a life-threatening combination of complex cardiac arrhythmia and hypokinesia. If a syndromic disorder is suspected in the neonatal intensive care unit (NICU) setting, rapid WES is a useful, non-invasive diagnostic tool in critically ill ELBW infants

Novel Genetic and Phenotypic Expansion in GOSR2-Related Progressive Myoclonus Epilepsy

Biallelic variants in the Golgi SNAP receptor complex member 2 gene (GOSR2) have been reported in progressive myoclonus epilepsy with neurodegeneration. Typical clinical features include ataxia and areflexia during early childhood, followed by seizures, scoliosis, dysarthria, and myoclonus. Here, we report two novel patients from unrelated families with a GOSR2-related disorder and novel genetic and clinical findings. The first patient, a male compound heterozygous for the GOSR2 splice site variant c.336+1G>A and the novel c.364G>A,p.Glu122Lys missense variant showed global developmental delay and seizures at the age of 2 years, followed by myoclonus at the age of 8 years with partial response to clonazepam. The second patient, a female homozygous for the GOSR2 founder variant p.Gly144Trp, showed only mild fine motor developmental delay and generalized tonic–clonic seizures triggered by infections during adolescence, with seizure remission on levetiracetam. The associated movement disorder progressed atypically slowly during adolescence compared to its usual speed, from initial intention tremor and myoclonus to ataxia, hyporeflexia, dysmetria, and dystonia. These findings expand the genotype–phenotype spectrum of GOSR2-related disorders and suggest that GOSR2 should be included in the consideration of monogenetic causes of dystonia, global developmental delay, and seizures.Medicine, Faculty ofNon UBCBiochemistry and Molecular Biology, Department ofReviewedFacultyResearcherGraduateOthe