Late-onset Tay-Sachs disease presenting with a neuromuscular phenotype-a case series.

BACKGROUND AND PURPOSE: Tay-Sachs disease is a rare and often fatal, autosomal recessive, lysosomal storage disease. Deficiency in ß-hexosaminidase leads to accumulation of GM2 ganglioside resulting in neuronal swelling and degeneration. Typical onset is in infancy with developmental regression and early death. Late-onset Tay-Sachs disease (LOTS) is extremely rare, especially in the non-Ashkenazi Jewish population, and is characterized by a more indolent presentation typically encompassing features of cerebellar and anterior horn cell dysfunction in addition to extrapyramidal and neuropsychiatric symptoms. CASES: A case series of four unrelated patients of non-Ashkenazi Jewish origin with a predominantly, and in some cases pure, neuromuscular phenotype with evidence of a motor neuronopathy on electromyography is presented. Cerebellar atrophy, reported to be a ubiquitous feature in LOTS, was absent in all patients. CONCLUSION: This case series provides evidence to support a pure neuromuscular phenotype in LOTS, which should be considered in the differential diagnosis of anterior horn cell disorders.

Diagnostic Tips from a Video Series and Literature Review of Patients with Late-Onset Tay-Sachs Disease.

Background: Late-Onset Tay-Sachs (LOTS) disease is a rare, progressive neurological condition that can dramatically affect the life of these patients. The diagnosis of LOTS is easily missed because of the multifaced presentation of these patients, who can initially be assessed by neuromuscular or movement disorder specialists, or psychiatrists. Clinical trials are now becoming available for LOTS. Therefore, early diagnosis can be detrimental for these patients and for insuring informative research outcomes. Methods: We characterized a cohort of nine patients with LOTS through a detailed clinical and video description. We then reviewed the available literature regarding the clinical description of patients with LOTS. Our findings were summarized based on the predominant phenotype of presentation to highlight diagnostic clues to guide the diagnosis of LOTS for different neurology specialists (neuromuscular, movement disorders) and psychiatrist. Results: We described a cohort of 9 new patients with LOTS seen at our clinic. Our literature review identified 76 patients mainly presenting with a neuromuscular, cerebellar, psychiatric, stuttering, or movement disorder phenotype. Diagnostic tips, such as the triceps sign, distinct speech patterns, early psychiatric presentation and impulsivity, as well as neurological symptoms (cerebellar or neuromuscular) in patients with a prominent psychiatric presentation, are described. Discussion: Specific diagnostics clues can help neurologists and psychiatrists in the early diagnosis of LOTS disease. Our work also represent the first video presentation of a cohort of patients with LOTS that can help different specialists to familiarize with these features and improve diagnostic outcomes. Highlights: Late-Onset Tay-Sachs (LOTS) disease, a severe progressive neurological condition, has multifaced presentations causing diagnostic delays that can significantly affect research outcomes now that clinical trials are available. We highlight useful diagnostic clues from our cohort (including the first video representation of a LOTS cohort) and comprehensive literature review.

Natural History of Adult Patients with GM2 Gangliosidosis.

OBJECTIVE: GM2 gangliosidoses are lysosomal diseases due to biallelic mutations in the HEXA (Tay-Sachs disease [TS]) or HEXB (Sandhoff disease [SD]) genes, with subsequent low hexosaminidase(s) activity. Most patients have childhood onset, but some experience the first symptoms during adolescence/adulthood. This study aims to clarify the natural history of adult patients with GM2 gangliosidosis. METHODS: We retrospectively described 12 patients from a French cohort and 45 patients from the literature. RESULTS: We observed 4 typical presentations: (1) lower motoneuron disorder responsible for proximal lower limb weakness that subsequently expanded to the upper limbs, (2) cerebellar ataxia, (3) psychosis and/or severe mood disorder (only in the TS patients), and (4) a complex phenotype mixing the above 3 manifestations. The psoas was the first and most affected muscle in the lower limbs, whereas the triceps and interosseous were predominantly involved in the upper limbs. A longitudinal study of compound motor action potentials showed a progressive decrease in all nerves, with different kinetics. Sensory potentials were sometimes abnormally low, mainly in the SD patients. The main brain magnetic resonance imaging feature was cerebellar atrophy, even in patients without cerebellar symptoms. The prognosis was mainly related to gait disorder, as we showed that beyond 20 years of disease evolution, half of the patients were wheelchair users. INTERPRETATION: Improved knowledge of GM2 gangliosidosis in adults will help clinicians achieve correct diagnoses and better inform patients on the evolution and prognosis. It may also contribute to defining proper outcome measures when testing emerging therapies. ANN NEUROL 2020;87:609-617.

Amyotrophy, cerebellar impairment and psychiatric disease are the main symptoms in a cohort of 14 Czech patients with the late-onset form of Tay-Sachs disease.

BACKGROUND: Tay-Sachs disease (TSD) is an inherited neurodegenerative disorder caused by a lysosomal ß-hexosaminidase A deficiency due to mutations in the HEXA gene. The late-onset form of disease (LOTS) is considered rare, and only a limited number of cases have been reported. The clinical course of LOTS differs substantially from classic infantile TSD. METHODS: Comprehensive data from 14 Czech patients with LOTS were collated, including results of enzyme assays and genetic analyses. RESULTS: 14 patients (9 females, 5 males) with LOTS were diagnosed between 2002 and 2018 in the Czech Republic (a calculated birth prevalence of 1 per 325,175 live births). The median age of first symptoms was 21 years (range 10-33 years), and the median diagnostic delay was 10.5 years (range 0-29 years). The main clinical symptoms at the time of manifestation were stammering or slurred speech, proximal weakness of the lower extremities due to anterior horn cell neuronopathy, signs of neo- and paleocerebellar dysfunction and/or psychiatric disorders. Cerebellar atrophy detected through brain MRI was a common finding. Residual enzyme activity was 1.8-4.1% of controls. All patients carried the typical LOTS-associated c.805G>A (p.Gly269Ser) mutation on at least one allele, while a novel point mutation, c.754C>T (p.Arg252Cys) was found in two siblings. CONCLUSION: LOTS seems to be an underdiagnosed cause of progressive distal motor neuron disease, with variably expressed cerebellar impairment and psychiatric symptomatology in our group of adolescent and adult patients. The enzyme assay of ß-hexosaminidase A in serum/plasma is a rapid and reliable tool to verify clinical suspicions.

Late-onset Tay-Sachs disease: phenotypic characterization and genotypic correlations in 21 affected patients.

PURPOSE: The purpose of this study was to describe the phenotype (and corresponding genotype) of adult patients with late-onset Tay-Sachs disease, a clinical variant of the GM2-gangliosidoses. METHODS: A comprehensive physical examination, including neurological assessments, was performed to establish the current disease pattern and severity. In addition, the patients' past medical histories were reviewed. The patients' alpha-subunit mutations (beta-Hexosaminidase A genotype) were determined and correlated with their corresponding clinical findings and disease course. RESULTS: Twenty-one patients (current mean age: 27.0 years; range: 14-47 years) were identified. The pedigree revealed a relative with the "classic" infantile or late-onset form of Tay-Sachs disease in four (out of 18) unrelated families. The patients were predominantly male (15/21 individuals) and of Ashkenazi Jewish ancestry (15/18 families). Mean age at onset was 18.1 years; balance problems and difficulty climbing stairs were the most frequent presenting complaints. In several cases, the diagnosis was delayed (mean age at diagnosis: 27.0 years). Analysis of the beta-hex A gene revealed the G269S mutation as the most common disease allele; found in homozygosity (N = 1) or heterozygosity (N = 18; including 2 sib pairs). Disease onset (age 36 years) was delayed and progression relatively slower in the homozygous G269S patient. Two siblings (ages 28 and 31 years), of non-Jewish ancestry, were compound heterozygotes (TATC1278/W474C); their clinical course is dominated by psychiatric problems. Brain imaging studies revealed marked cerebellar atrophy in all patients (N = 18) tested, regardless of disease stage. CONCLUSIONS: Late-onset Tay-Sachs disease is an infrequent disorder and the diagnosis is often missed or delayed (by approximately 8 years). Early on, the majority of patients develop signs of either cerebellar or anterior motor neuron involvement. Affected individuals may also develop psychotic episodes. In most cases, the later-onset of expression results from the presence of at least one allele (usually the G269S mutation), associated with residual enzyme (beta-hexosaminidase A) activity. A positive family history is a valuable clue, enabling early diagnosis. Nonspecific cerebellar atrophy on brain imaging is another important finding. This entity should be considered among patients presenting with speech, gait, and balance problems, and those with psychiatric disorders even when focal neurologic deficits may be initially absent. Accurate diagnosis will permit appropriate genetic counseling regarding disease prognosis and reproductive risks.

Late onset Tay-Sachs disease in mice with targeted disruption of the Hexa gene: behavioral changes and pathology of the central nervous system.

Tay-Sachs disease is an autosomal recessive neurodegenerative disease resulting from a block in the hydrolysis of GM2 ganglioside, an intermediate in ganglioside catabolism. The mouse model of Tay-Sachs disease (Hexa -/-) has been described as behaviorally indistinguishable from wild type until at least 1 year of age due to a sialidase-mediated bypass of the metabolic defect that reduces the rate of GM2 ganglioside accumulation. In this study, we have followed our mouse model to over 2 years of age and have documented a significant disease phenotype that is reminiscent of the late onset, chronic form of human Tay-Sachs disease. Onset occurs at 11-12 months of age and progresses slowly, in parallel with increasing storage of GM2 ganglioside. The disease is characterized by hind limb spasticity, weight loss, tremors, abnormal posture with lordosis, possible visual impairment, and, late in the disease, muscle weakness, clasping of the limbs, and myoclonic twitches of the head. Immunodetection of GM2 ganglioside showed that storage varies widely in different regions, but is most intense in pyriform cortex, hippocampus (CA3 field, subiculum), amygdala, hypothalamus (paraventricular supraoptic, ventromedial and arcuate nuclei, and mammilary body), and the somatosensory cortex (layer V) in 1- to 2-year-old mutant mice. We suggest that the Tay-Sachs mouse model is a phenotypically valid model of disease and may provide for a reliable indicator of the impact of therapeutic strategies, in particular geared to the late onset, chronic form of human Tay-Sachs disease.

Neuropsychiatric aspects of the adult variant of Tay-Sachs disease.

Tay-Sachs disease (a GM2 gangliosidosis) is an inherited neuronal storage disease that can affect individuals across the age spectrum. Psychosis is reported in 30% to 50% of adult-onset patients, and many are misdiagnosed with schizophrenia. Mood disorders are present in more than 25% and cognitive impairment in more than 20%. Treatment of psychosis with neuroleptics may not have a favorable risk/benefit ratio, but treatment with benzodiazepines or electroconvulsive therapy may be efficacious. Metabolic diseases such as gangliosidosis are probably under-recognized as causes of neuropsychiatric illness. Increased awareness of these disorders will lead to accurate diagnosis, appropriate treatment selection, and genetic counseling.

Benefits and burdens of genetic carrier identification.

This qualitative study examined experiences of adults requesting genetic-carrier testing for four autosomal-recessive and X-linked-recessive disorders. The sample consisted of 34 adults with a positive family history or membership in an ethnic group at risk for the inherited disorder. A semistructured interview guide was used to collect data during an interview 1 month after receipt of test results. Noncarriers experienced benefits of emotional relief and freedom to move ahead with reproductive planning. Carriers experienced burdens of sadness and loss of reproductive expectations. Some subjects in both groups experienced difficulty disclosing results to selected family members and expressed concerns regarding disclosure of testing to insurance providers.

Late-onset Tay-Sachs disease presenting as catatonic schizophrenia: diagnostic and treatment issues.

BACKGROUND: It is not commonly appreciated that patients with hexosaminidase A deficiency (Tay-Sachs disease) can first present in adulthood with psychiatric illness. METHOD: A 17-year-old non-Jewish male patient was referred with a history of treatment-resistant catatonic schizophrenia. We uncovered coexistent neurologic abnormalities and evidence of cognitive decline. Metabolic screening revealed a severe deficiency of beta-hexosaminidase A. We reviewed the literature on late-onset gangliosidosis with attention to (1) the nature of the associated psychiatric and neurologic abnormalities and (2) the treatment of psychosis in these patients. RESULTS: The patient's catatonia responded promptly to benzodiazepine therapy. Treatment with neuroleptic medication resulted in the rapid development of neuroleptic malignant syndrome. The patient was thereafter maintained on lorazepam with resolution of his acute psychiatric disturbances and unexpected improvement in his neurologic status. CONCLUSION: Patients with hexosaminidase deficiency may first present in adolescence or adulthood with psychiatric illness, particularly schizophrenic-like psychosis. The presence of speech disturbance, gait abnormalities, movement disorders, and cognitive decline may indicate an underlying metabolic disorder. The use of traditional neuroleptics to treat the psychosis in such individuals may produce an unacceptably high risk/benefit ratio. Benzodiazepines may ameliorate the psychiatric and neurologic abnormalities in these patients.

A family history study of schizophrenia spectrum disorders suggests new candidate genes in schizophrenia and autism.

To limit genetic heterogeneity, this study focused on the widely extended pedigrees of Ashkenazi Jewish schizophrenic and autistic probands, to determine if similar causal mechanisms might obtain for both conditions. At least two previous epidemiological studies have demonstrated increased risk for schizophrenia in Ashkenazi Jews. The hypothesis posed is that increased prevalence of various rare autosomal recessive diseases among the Ashkenazim might contribute to the increased vulnerability to schizophrenia and to autism in this large genetic isolate. Rates of amyotrophic lateral sclerosis (ALS) and bleeding disorders were significantly increased among relatives of schizophrenic and autistic probands, compared to relatives of normal probands. These results suggest new candidate loci in schizophrenia and autism, particularly the chromosome 15q23-24 locus of the hexosaminidase A gene, causing various GM2 gangliosidoses, and the 21q22.1-q22.2 loci of the antioxidant, superoxide dismutase gene, and a cytokine receptor gene.

Medical conditions in Ashkenazi schizophrenic pedigrees.

To limit the genetic heterogeneity of schizophrenia, this study focused on the widely extended pedigrees of Ashkenazi Jewish schizophrenia probands. The hypothesis posed is that the increased prevalence among the Ashkenazim of the rare lysosomal enzyme disorders, Tay Sachs disease (TDS), caused by low levels of hexosaminidase A, and Gaucher's disease (GD), caused by low levels of glucocerebrosidase, might contribute to the demonstrated increased vulnerability to schizophrenia in this ethnic group. Signs and symptoms characterizing the candidate illnesses were systematically queried by the family history method. Rates and relative risks for symptoms characterizing these disorders and for several nonautosomal illnesses associated with TSD and/or GD (i.e., amyotrophic lateral sclerosis and Hodgkin's disease, leukemia and lymphoma) are significantly elevated in the schizophrenia pedigrees, compared to controls. The conditions with elevated rates and risks have been associated with chromosomal regions 1q21 and 15q23-q24. These areas are suggested as candidate regions for future targeted deoxyribonucleic acid (DNA) research in schizophrenia.

Neuropsychiatric aspects of adult-onset Tay-Sachs disease: two case reports with several new findings.

Deficiency of hexosaminidase A causes the GM2 gangliosidosis known as Tay-Sachs disease. It is now known that this condition has several late-onset variants that cause numerous neuropsychiatric disturbances. Early recognition is important because treatment with phenothiazines and heterocyclic antidepressants may worsen the course. The authors report two cases with several new findings, including prominent psychiatric symptoms without psychosis early in the course of the illness.

Effects of genetic screening on perceptions of health: a pilot study.

The aim of the current study was to determine how carriers of a recessive gene, which confers no risk to their own health, perceive their health, relative to non-carriers. Perceptions of health in three groups were compared: those screened and found to carry the gene for Tay-Sachs disease, those screened and not found to carry the gene for Tay-Sachs disease, and a community based sample who, it was presumed, had not undergone screening. The groups did not differ in their perceptions of their current health or their past health. Carriers, however, viewed their future health with less optimism than the other two groups. The causes and consequences of this altered perception need to be explored in future studies. With the advent of population based screening for cystic fibrosis carrier status, these results highlight the importance of assessing in detail people's experiences of screening before the introduction of any mass genetic screening programmes.

Psychiatric features of adult GM2 gangliosidosis.

The report describes three unrelated Ashkenazi Jewish women with adult GM2 gangliosidosis in whom mental symptoms were prominent, mimicking different psychiatric disorders, and thus delaying accurate diagnosis.

A group for parents of children with fatal genetic illnesses.

Parents whose children have progressive genetic disorders, such as Tay-Sachs, are confronted with a myriad of painful and compelling issues. This paper describes a long-term, open-ended group set up to allow parents of such children to work together on mutual concerns. The process of collaboration, the evolving structure of the group, and the challenges of working with this special population are explored.

Neuropsychological deficits in obligatory heterozygotes for metachromatic leukodystrophy.

Two groups of heterozygotes, one for metachromatic leukodystrophy (MLD) and the other for Tay-Sachs disease, were given a battery of neuropsychological tests, a standard neurological examination, and an EEG. Neurological and EEG findings were unremarkable for both groups. The MLD heterozygotes showed deficits in the neuropsychological tests involving spatial or constructional components, but not in tests involving language skills. The Tay-Sachs heterozygotes showed no consistent deficit on any component of the neuropsychological tests.