BACKGROUND AND PURPOSE:

Ataxia-telangiectasia (A-T) is a rare neurodegenerative disease, due to A-T mutated (ATM) gene mutations, which typically presents with signs of progressive neurological dysfunction, cerebellar ataxia and uncoordinated movements. A-T severely affects patients' quality of life. Successful treatment options are still not available. The aim of this multicenter study, performed with a blind evaluation procedure, was to define the minimal effective dosage of oral betamethasone, thus preventing the occurrence of side effects.

METHODS:

Nine A-T patients were enrolled to receive betamethasone at increasing dosages of 0.001, 0.005 and 0.01 mg/kg/day. Neurological assessment and the evaluation of quality of life were performed through the Scale for the Assessment and Rating of Ataxia and the Italian version of the Childhood Health Assessment Questionnaire (CHAQ) at each time-point. The drug safety profile was evaluated. Patients were categorized as responders, partial responders and non-responders.

RESULTS:

Four of nine patients had a benefit at a dose of 0.005 mg/kg/day of oral betamethasone. Using the higher dosage, only one additional patient had a positive response. Conversely, a daily dose of 0.001 mg/kg was ineffective. A correlation between the serum adrenocorticotropic hormone levels and the clinical response was observed. Five of 30 CHAQ items improved in four patients.

CONCLUSIONS:

These data suggest that a short-term betamethasone oral treatment, at a daily dosage of 0.005 mg/kg, is effective in some patients. Pre-existing risk factors for side effects should be taken into account before therapy.

© 2018 EAN.

Ataxia telangiectasia (AT) is a rare genetic disease, still incurable, resulting from biallelic mutations in the ataxia telangiectasia-mutated (ATM) gene. Recently, short term treatment with glucocorticoid analogues improved neurological symptoms characteristic of this syndrome. Nevertheless, the molecular mechanism involved in glucocorticoid action in AT patients is not yet known. Here we describe, for the first time in mammalian cells, a short direct repeat-mediated noncanonical splicing event induced by dexamethasone, which leads to the skipping of mutations upstream of nucleotide residue 8450 of ATM coding sequence. The resulting transcript provides an alternative ORF translated in a new ATM variant with the complete kinase domain. This miniATM variant was also highlighted in lymphoblastoid cell lines from AT patients and was shown to be likely active. In conclusion, dexamethasone treatment may partly restore ATM activity in ataxia telangiectasia cells by a new molecular mechanism that overcomes most of the mutations so far described within this gene.

Hereditary deficiencies in DNA damage signaling are invariably associated with cancer predisposition, immunodeficiency, radiation sensitivity, gonadal abnormalities, premature aging, and tissue degeneration. ATM kinase has been established as a central player in DNA double-strand break repair and its deficiency causes ataxia telangiectasia, a rare, multi-system disease with no cure. So ATM represents a highly attractive target for the development of novel types of gene therapy or transplantation strategies. Atm tamoxifen-inducible mouse models were generated to explore whether Atm reconstitution is able to restore Atm function in an Atm-deficient background. Body weight, immunodeficiency, spermatogenesis, and radioresistance were recovered in transgenic mice within 1 month from Atm induction. Notably, life span was doubled after Atm restoration, mice were protected from thymoma and no cerebellar defects were observed. Atm signaling was functional after DNA damage in vivo and in vitro. In summary, we propose a new Atm mouse model to investigate novel therapeutic strategies for ATM activation in ataxia telangiectasia disease.

This study compared the antioxidant status and major lipophilic antioxidants in patients with ataxia-telangiectasia (AT) and Nijmegen breakage syndrome (NBS). Total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), and concentrations of coenzyme Q10 (CoQ10) and vitamins A and E were estimated in the plasma of 22 patients with AT, 12 children with NBS, and the healthy controls. In AT patients, TAS (median 261.7 μmol/L) was statistically lower but TOS (496.8 μmol/L) was significantly elevated in comparison with the healthy group (312.7 μmol/L and 311.2 μmol/L, resp.). Tocopherol (0.8 μg/mL) and CoQ10 (0.1 μg/mL) were reduced in AT patients versus control (1.4 μg/mL and 0.3 μg/mL, resp.). NBS patients also displayed statistically lower TAS levels (290.3 μmol/L), while TOS (404.8 μmol/L) was comparable to the controls. We found that in NBS patients retinol concentration (0.1 μg/mL) was highly elevated and CoQ10 (0.1 μg/mL) was significantly lower in comparison with those in the healthy group. Our study confirms disturbances in redox homeostasis in AT and NBS patients and indicates a need for diagnosing oxidative stress in those cases as a potential disease biomarker. Decreased CoQ10 concentration found in NBS and AT indicates a need for possible supplementation.

A 19-year-old ataxia-telangiectasia patient with T-cell prolymphocytic leukemia harbored 2 JAK3-activating hotspot mutations.The patient suffered toxicities with chemotherapy, but demonstrated a clinical response to novel use of a JAK3 inhibitor (tofacitinib).

OBJECTIVE:

Ataxia telangiectasia (A-T) is a rare genetic disease involving multiple organs, but, to our knowledge, data on long-term gastrointestinal and nutritional involvement are scarce. The aim of this study was to longitudinally review the nutritional and gastrointestinal aspects of A-T.

METHODS:

This was a retrospective chart review of patients followed from 1986 to 2015 at one center. Demographic, laboratory, and nutritional data were retrieved. Body mass index (BMI) values were converted to BMI Z-score (BMI-Z). Caloric intake was estimated by food diaries and compared with estimated energy requirements for sex and age with a physical activity level factor for light physical activity.

RESULTS:

The study included 53 patients (28 males [53%], ages 14.6 ± 5.2 y). BMI-Z was inversely correlated with age (r = 0.48; P < 0.004). A decline below minimal BMI percentiles was observed after the age of 4 y in boys and 7 y in girls. The relative percentage of caloric intake decreased with age (r = -0.5; P < 0.002), and was positively correlated with BMI-Z (r = 0.35; P < 0.05). Presence of cough during meals was associated with recurrent lower respiratory tract infections (Fisher exact test, P < 0.01). Gastrostomy tubes were inserted in 12 patients, leading to improvement in BMI-Z from -5.1 ± 2.4 to -4 ± 2.9 (P < 0.05).

CONCLUSIONS:

There is a progressive growth failure and low nutritional intake with age in patients with A-T, starting in early childhood in males, and more prominent in patients with cough and choking during meals. A proactive approach and insertion of a percutaneous gastrostomy tube as soon as the BMI-Z starts to decrease should be considered.

Copyright © 2017 Elsevier Inc. All rights reserved.

Ataxia Telangiectasia (AT) is named after the two key clinical features that characterize its classical phenotype, namely a progressive cerebellar gait disorder (ataxia) and vascular anomalies (telangiectasias) visible in the conjunctivae and skin. AT is an autosomal recessively inherited disorder, caused by mutations in the ATM gene that encodes the ATM protein. While the ataxia is subject of many publications, the telangiectasias are under emphasised. We here describe the observation that the absence or presence of ATM protein and the level of residual ATM kinase activity are related to the occurrence of telangiectasias and describe the clinical consequences of these vascular malformations. Finally, we hypothesize that ATM dysfunction dysregulates angiogenesis.

Ataxia-telangiectasia (AT) is a rare autosomal recessive neurodegenerative disease caused by mutations in the ATM gene with progressive neurological dysfunction, multisystem abnormalities and cancer predisposition. Classically, AT is associated with cerebellar ataxia, oculocutaneous telangiectasia and oculomotor apraxia. The aim of this review is to describe the movement disorders observed in patients with AT. Movement disorders in AT patients described in the literature are reviewed. The selected articles were analyzed with a focus on clinical presentation, presence of movement disorders, and atypical cases or variants of the syndrome. In AT patients, particularly adults, chorea and dystonia are the most common movement disorders, besides cerebellar ataxia. Myoclonus, tremor and parkinsonism have been described less frequently in patients with AT. Archetypal findings, such as oculocutaneous abnormalities may not be uniformly present. AT can present with different movement disorders, in isolation or combined, with or without cerebellar ataxia or oculocutaneous telangiectasias. Neurologists with expertise in movement disorders should be aware of AT when investigating patients with movement disorders of unknown etiology.

OBJECTIVE:

To investigate cerebellar dysfunctions and quantitatively characterize specific oculomotor changes in ataxia-telangiectasia-like disorder (ATLD), a rare autosomal recessive disease caused by mutations in the MRE11 gene. Additionally, to further elucidate the pathophysiology of cerebellar damage in the ataxia-telangiectasia (AT) spectrum disorders.

METHODS:

Saccade dynamics, metrics, and visual fixation deficits were investigated in two Italian adult siblings with genetically confirmed ATLD. Visually guided saccades were compared with those of 40 healthy subjects. Steady fixation was tested in primary and eccentric positions. Quantitative characterization of saccade parameters, saccadic intrusions (SI), and nystagmus was performed.

RESULTS:

Patients showed abnormally hypermetric and fast horizontal saccades to the left and greater inaccuracy than healthy subjects in all saccadic eye movements. Eye movement abnormalities included slow eye movements that preceded the initial saccade. Horizontal and vertical spontaneous jerk nystagmus, gaze-evoked, and rebound nystagmus were evident. Fixation was interrupted by large square-wave jerk SI and macrosaccadic oscillations.

CONCLUSION:

Slow eye movements accompanying saccades, SI, and cerebellar nystagmus are frequently seen in AT patients, additionally our ATLD patients showed the presence of fast and hypermetric saccades suggesting damage of granule cell-parallel fiber-Purkinje cell synapses of the cerebellar vermis. A dual pathogenetic mechanism involving neurodevelopmental and neurodegenerative changes is hypothesized to explain the peculiar phenotype of this disease.

OBJECTIVE:

To evaluate the potential link between systemic inflammation and impaired lung function in people with ataxia-telangiectasia (A-T), we hypothesized that serum levels of interleukin (IL)-6, a proinflammatory cytokine, would correlate inversely with lung function in subjects with A-T.

STUDY DESIGN:

Consecutive subjects with A-T were recruited from the Johns Hopkins Outpatient A-T Clinical Center. Serum levels of IL-6 and 8 were measured by enzyme-linked immunosorbent assay. Spirometry was performed in subjects ≥ 6 years of age on the same day that serum was obtained for measurements of cytokines.

RESULTS:

Approximately 80% of subjects had elevated serum IL-6 levels (> 1.0 pg/mL). No association was found between elevated IL-6 and age. Elevated IL-8 levels were found in 23.6% of subjects, and all subjects with elevated IL-8 levels had elevated IL-6 levels. Subjects with elevated IL-6 levels (mean: 6.14 ± 7.47 pg/mL) had significantly lower mean percent forced vital capacity (FVC%, 50.5% ± 17.8%) compared with subjects with normal serum IL-6 levels(FVC% of 66.2 ± 16.1, P = .018). Greater IL-6 levels were associated with lower FVC% even after adjustment for receiving gamma globulin therapy (P = .024) and supplemental nutrition (P = .055).

CONCLUSIONS:

An association was found between elevated serum IL-6 levels and lower lung function in subjects with A-T. In addition, subjects with both elevated IL-6 and IL-8 had the lowest mean lung function. These findings indicate that markers for systemic inflammation may be useful in identifying individuals with A-T at increased risk for lower lung function and may help in assessing response to therapy.

Copyright © 2016 Elsevier Inc. All rights reserved.

BACKGROUND AND AIMS:

Evaluate the nutritional status, plasma concentration of vitamin E and markers of cardiovascular risk in ataxia telangiectasia (AT) patients.

METHODS:

Cross-sectional study with 13 patients with AT and 22 healthy controls, evaluating the following factors: nutritional status, food intake, lipid profile, plasma concentration of vitamin E, malondialdehyde and high sensitivity C-reactive protein, linking them with atherosclerosis risk in AT patients.

RESULTS:

Average age was 14.6 in the AT group, 30.8% were malnourished and 23.1% had stunting. A greater impairment of lean body mass was found in these patients. Concentrations of triglycerides (TG), total cholesterol (CT), LDL-c, non-HDL cholesterol (NHDL-c) were significantly higher in patients and HDL-c, lower. Vitamin E/total lipids and vitamin E/TG ratios were lower in the AT group, and significant inverse correlation between these ratios and NHDL-c, CT/HDL-c, and LDL-c/HDL-c, log TG/HDL-c was observed in the AT group. Alanine aminotransferase correlated directly and significantly with NHDL-c, CT/HDL-c and LDL-c/HDL-c, in patients.

CONCLUSION:

The alterations of lipid metabolism biomarkers suggestive of atherosclerotic risk of male AT patients coupled with lower vitamin E/total lipids ratio and low lean body mass may complicate the clinical course of the disease and emphasizes the importance of multidisciplinary care, routine monitoring of cardiovascular biomarkers and appropriate nutritional guidance.

2015 S. Karger AG, Basel.

OBJECTIVE:

Ataxia telangiectasia (A-T) is a rare genetic multiorgan disease. Although gastrointestinal involvement is known, hepatic involvement in A-T has not been investigated. We aimed to study the hepatic involvement in a large cohort of patients with A-T.

METHODS:

A retrospective review of patients, studied from January 1986 to January 2015 at a National A-T Center. Clinical data including demographic, genetic, laboratory, nutritional, radiographic, and histological data were retrieved.

RESULTS:

Fifty-three patients, 27 (49%) boys, age 14.6 ± 5.2 years (range 5.9-26.1 years), were included. Twenty-three patients (43.4%), age 9.9 ± 5.1 years, had consistently abnormal liver enzymes. The mean enzyme levels were alanine aminotransferase 76.8 ± 73.8 IU/L, aspartate aminotransferase 70 ± 50 IU/L, alkaline phosphatase 331 ± 134 IU/L, and gamma glutamyl transferase 114.7 ± 8 IU/L. Evaluation of other etiology of liver disease was negative. Ultrasonography revealed fatty liver in 9 of them (39%). Liver biopsy was performed in 2 patients, revealing mild-to-moderate steatosis in both, and fibrosis in 1 patient. Progression to advanced liver disease occurred in 2 of 23 (9%) patients within 2 to 5 years. Dyslipidemia was significantly associated with abnormal liver enzymes: 3 of 30 (10%) patients without abnormal liver enzymes versus 10 of 23 (45.5%) patients with abnormal liver enzymes, respectively (P < 0.05, Fisher exact test). No correlation was found between hepatic involvement and HbA1C, sex, presence of malignancy, or type of mutation.

CONCLUSIONS:

Abnormal liver enzymes and fatty liver are common in patients with A-T and may progress to advanced liver disease at a young age. These findings are novel and implicate that patients with A-T with abnormal liverenzymes should be evaluated for the presence of liver disease.

BACKGROUND:

Ataxia-telangiectasia (A-T) is a devastating human autosomal recessive disorder that causes progressive cerebellar ataxia, immunodeficiency, premature aging, chromosomal instability and increased cancer risk. Affected patients show growth failure, poor weight gain, low body mass index (BMI), myopenia and increased fatigue during adolescence. The prevalence of alterations in body composition, muscle strength and hormonal status has not been well described in classical A-T patients. Additionally, no current guidelines are available for the assessment and management of these changes.

METHODS:

We analyzed body composition, manual muscle strength and hormonal status in 25 A-T patients and 26 age-matched, healthy controls. Bioelectrical impedance analysis (BIA) was performed to evaluate the bodycomposition, fat-free mass (FFM), body cell mass (BCM), extracellular matrix (ECM), phase angle (PhA), fat mass (FM) and ECM to BCM ratio. Manual muscle strength was measured using a hydraulic hand dynamometer.

RESULTS:

The BMI, FFM and PhA were significantly lower in A-T patients than in controls (BMI 16.56 ± 3.52 kg/m(2) vs. 19.86 ± 3.54 kg/m(2); Z-Score: -1.24 ± 1.29 vs. 0.05 ± 0.92, p <0.001; FFM 25.4 ± 10.03 kg vs. 41.77 ± 18.25 kg, p < 0.001; PhA: 4.6 ± 0.58° vs. 6.15 ± 0.88°, p < 0.001). Manual muscle strength was significantly impaired in A-T patientscompared with controls (10.65 ± 10.97 kg vs. 26.8 ± 30.39 kg, p < 0.0001). In addition, cortisol and dehydroepiandrosterone sulfate (DHEAS) levels were significantly lower in A-T patients than in controls.

CONCLUSION:

Altered body composition, characterized by depleted BMI, PhA and BCM; by the need to sit in a wheelchair; by altered hormone levels; and by poor muscle strength, is a major factor underlying disease progression and increased fatigue in A-T patients.

TRIAL REGISTRATION:

ClinicalTrials.gov NCT02345200.

AIM:

Ataxia-telangiectasia (A-T) is a rare genomic syndrome resulting in severe disability. Chronic childhood disorders can profoundly influence growth and development. Nutrition-related issues in A-T are not well described, and there are no nutritional guidelines. This study investigated the nutrition-related characteristics and behaviours of Australian A-T patients attending a national clinic.

METHODS:

A cross-sectional analysis of 13 A-T patients (nine females; aged: 4-23 years): nutritional status was assessed by anthropometric and body cell mass (BCM) calculations. Parents reported their child's diet history and physical and behavioural factors that affect nutrition including fatigue and need for assistance.

RESULTS:

Ten (77%) had short stature (height for age z scores <-1), and seven (54%) were underweight for height (weight/height z scores <-1). Significant malnutrition (BCM z scores <-2) was detected in nine (69%) including the one adult who was severely malnourished. Malnutrition increased significantly with age (BCM for height z scores and age, r = -0.937, P < 0.001). Eight (62%) patients ate poorly compared with estimated energy requirement for weight. Poor diet quality was characterised by high fat and sugar choices. Parents reported significant nutritional barriers as chronic tiredness and the need for care giver assistance with meals.

CONCLUSIONS:

This study confirms profound malnutrition in Australian A-T patients. Poor intakes and diet quality suggest the need for early nutrition intervention. Ongoing support for families and early discussions on tube feeding are required to address changing needs in childhood and likely nutritional decline into adulthood. A prospective study is required to assess feasibility and effectiveness of nutrition interventions in young people with A-T.

© 2015 The Authors. Journal of Paediatrics and Child Health © 2015 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

AIM:

To assess the relationship between genotype and neurological progression in ataxia-telangiectasia (A-T).

METHODS:

Clinical and laboratory data were extracted retrospectively from the records of patients attending the UK National Ataxia-Telangiectasia Clinic. Neurological assessments were performed using the A-T Index (Crawford Score) and the A-T Neurological Examination Scale Toolkit (A-T NEST). Variables influencing phenotype were identified by using an information-theoretic approach starting from a maximal model to generate estimates of coefficients for each variable. Per-individual progression was assessed for patients with three or more clinic attendances.

RESULTS:

The genotype could be determined for 125/135 patients. Crawford and A-T NEST scores were well correlated. For both scoring systems the estimated coefficients were significantly positive for Age x kinase activity but not Age x protein expression. Unlike the per-genotype analysis, the individual progression of neurological scores in the 34 patients that attended on three or more occasions was not smooth and linear (and in some cases improved over time).

INTERPRETATION:

Residual kinase activity confers a milder phenotype but there is no difference between kinase-dead and protein-null genotypes. The non-linear progression of individual patients' neurological scores may reflect biological complexity, day-to-day variability, limitations of the assessment methods or a combination of all three.

© 2016 Mac Keith Press.

Ataxia-telangiectasia (AT) is an autosomal recessive neurodegenerative disorder with immunodeficiency and an increased risk of developing cancer, caused by mutations in the ataxia-telangiectasia mutated (ATM) gene. Logically, blood relatives may also carry a pathogenic ATM mutation. Female carriers of such a mutation have an increased risk of breast cancer. Other health risks for carriers are suspected but have never been studied systematically. Consequently, evidence-based guidelines for carriers are not available yet. We systematically analyzed all literature and found that ATM mutation carriers have a reduced life expectancy because of mortality from cancer and ischemic heart diseases (RR 1.7, 95% CI 1.2-2.4) and an increased risk of developing cancer (RR 1.5, 95% CI 0.9-2.4), in particular breast cancer (RRwomen 3.0, 95% CI 2.1-4.5), and cancers of the digestive tract. Associations between ATM heterozygosity and other health risks have been suggested, but clear evidence is lacking. Based on these results, we propose that all female carriers of 40-50 years of age and female ATM c.7271T>G mutation carriers from 25 years of age onwards be offered intensified surveillance programs for breast cancer. Furthermore, all carriers should be made aware of lifestyle factors that contribute to the development of cardiovascular diseases and diabetes.

Ataxia-telangiectasia (A-T), or Louis-Bar syndrome, is a rare neurodegenerative disorder associated with immunodeficiency. For families with at least one affected child, timely A-T genotyping during any subsequent pregnancy allows the parents to make an informed decision about whether to continue to term when the fetus is affected. Mutations in the ATM gene, which is 150 kb long, give rise to A-T; more than 600 pathogenic variants in ATM have been characterized since 1990 and new mutations continue to be discovered annually. Therefore, limiting genetic screening to previously known SNPs by PCR or hybridization with microarrays may not identify the specific pathogenic genotype in ATM for a given A-T family. However, recent developments in next-generation sequencing technology offer prompt high-throughput full-length sequencing of genomic fragments of interest. This allows the identification of the whole spectrum of mutations in a gene, including any novel ones. We report two A-T families with affected children and current pregnancies. Both families are consanguineous and originate from Caucasian regions of Russia and Azerbaijan. Before our study, no ATM mutations had been identified in the older children of these families. We used ion semiconductor sequencing and an Ion AmpliSeq™ Inherited Disease Panel to perform complete ATM gene sequencing in a single member of each family. Then we compared the experimentally determined genotype with the affected/normal phenotype distribution in the whole family to provide unambiguous evidence of pathogenic mutations responsible for A-T. A single novel SNP was allocated to each family. In the first case, we found a mononucleotide deletion, and in the second, a mononucleotide insertion. Both mutations lead to truncation of the ATM protein product. Identification of the pathogenic mutation in each family was performed in a timely fashion, allowing the fetuses to be tested and diagnosed. The parents chose to continue with both pregnancies as both fetuses had a healthy genotype and thus were not at risk of A-T.

Ataxia-telangiectasia (A-T) is a rare genetic disorder caused by loss of function of the ataxia-telangiectasia-mutated kinase and is characterized by a predisposition to cancer, pulmonary disease, immune deficiency and progressive degeneration of the cerebellum. As animal models do not faithfully recapitulate the neurological aspects, it remains unclear whether cerebellar degeneration is a neurodevelopmental or neurodegenerative phenotype. To address the necessity for a human model, we first assessed a previously published protocol for the ability to generate cerebellar neuronal cells, finding it gave rise to a population of precursors highly enriched for markers of the early hindbrain such as EN1 and GBX2, and later more mature cerebellar markers including PTF1α, MATH1, HOXB4, ZIC3, PAX6, and TUJ1. RNA sequencing was used to classify differentiated cerebellar neurons generated from integration-free A-T and control induced pluripotent stem cells. Comparison of RNA sequencing data with datasets from the Allen Brain Atlas reveals in vitro-derived cerebellar neurons are transcriptionally similar to discrete regions of the human cerebellum, and most closely resemble the cerebellum at 22 weeks post-conception. We show that patient-derived cerebellar neurons exhibit disrupted gene regulatory networks associated with synaptic vesicle dynamics and oxidative stress, offering the first molecular insights into early cerebellar pathogenesis of ataxia-telangiectasia.

Ataxia-telangiectasia (A-T) a multisystem disorder primarily characterized by cerebellar degeneration, telangiectasia, immunodeficiency, cancer susceptibility and radiation sensitivity. Identification of the gene defective in this syndrome, ataxia-telangiectasia mutated gene (ATM), and further characterization of the disorder together with a greater insight into the function of the ATM protein have expanded our knowledge about the molecular pathogenesis of this disease. Area covered: In this review, we have attempted to summarize the different roles of ATM signaling that have provided new insights into the diverse clinical phenotypes exhibited by A-T patients. Expert commentary: ATM, in addition to DNA repair response, is involved in many cytoplasmic roles that explain diverse phenotypes of A-T patients. It seems accumulation of DNA damage, persistent DNA damage response signaling, and chronic oxidative stress are the main players in the pathogenesis of this disease.