ATAXIA TELANGIECTASIS. A DYSGAMMAGLOBULINAEMIA WITH DEFICIENT GAMMA-1-A (BETA-2-A)-GLOBULIN

The natural history of ataxia-telangiectasia (A-T): A systematic review

BACKGROUND

Ataxia-telangiectasia is an autosomal recessive, multi-system, and life-shortening disease caused by mutations in the ataxia-telangiectasia mutated gene. Although widely reported, there are no studies that give a comprehensive picture of this intriguing condition.

OBJECTIVES

Understand the natural history of ataxia-telangiectasia (A-T), as reported in scientific literature.

SEARCH METHODS

107 search terms were identified and divided into 17 searches. Each search was performed in PubMed, Ovid SP (MEDLINE) 1946-present, OVID EMBASE 1980 -present, Web of Science core collection, Elsevier Scopus, and Cochrane Library.

SELECTION CRITERIA

All human studies that report any aspect of A-T.

DATA COLLECTION AND ANALYSIS

Search results were de-duplicated, data extracted (including author, publication year, country of origin, study design, population, participant characteristics, and clinical features). Quality of case-control and cohort studies was assessed by the Newcastle-Ottawa tool. Findings are reported descriptively and where possible data collated to report median (interquartile range, range) of outcomes of interest.

MAIN RESULTS

1314 cases reported 2134 presenting symptoms. The most common presenting symptom was abnormal gait (1160 cases; 188 studies) followed by recurrent infections in classical ataxia-telangiectasia and movement disorders in variant ataxia-telangiectasia. 687 cases reported 752 causes of death among which malignancy was the most frequently reported cause. Median (IQR, range) age of death (n = 294) was 14 years 0 months (10 years 0 months to 23 years 3 months, 1 year 3 months to 76 years 0 months).

CONCLUSIONS

This review demonstrates the multi-system involvement in A-T, confirms that neurological symptoms are the most frequent presenting features in classical A-T but variants have diverse manifestations. We found that most individuals with A-T have life limited to teenage or early adulthood. Predominance of case reports, and case series demonstrate the lack of robust evidence to determine the natural history of A-T. We recommend population-based studies to fill this evidence gap.

Interstitial lung disease in patients with ataxia-telangiectasia

Ataxia-telangiectasia (A-T) is an autosomal-recessive multiorgan disease characterized by progressive neurologic deterioration in which the most common causes of death are diseases of the respiratory system and cancers. The aim of this retrospective study was to delineate the clinical, radiographic, and pathologic manifestations of the chronic progressive interstitial lung disease seen in patients with A-T. The medical records of 97 patients with A-T and chronic lung disease were reviewed. Interstitial lung disease (ILD) was specifically diagnosed in 25 of 97 patients. None of these patients had evidence of an infectious process preceding the onset of their lung disease, and none had lasting clinical improvement after treatment with antibiotics. Although many medications were used to treat their ILD, only treatment with systemic corticosteroids early in the course of their illness was associated with clinical and radiographic improvement. Nineteen of these 25 patients with ILD died within 24 months of the onset of their ILD, and of 7 patients treated with corticosteroids, 5 are still alive. Recognition of interstitial lung disease in patients with A-T and its early treatment could reduce or eliminate pulmonary disease as a leading cause of death for these patients.

Oligo-/monoclonal gammopathy and hypergammaglobulinemia in ataxia-telangiectasia. A study of 90 patients

We investigated the presence of hypergammaglobulinemia and oligo-/monoclonal gammopathy in 90 patients (from 80 families) with ataxia-telangiectasia ranging in age from 2 to 29 years. Of the 90 patients, 38.8% displayed hypergammaglobulinemia. An isolated increase in IgM was the most common finding (23.3%) followed by a simultaneous increase in IgM and IgG (8.8%), an isolated increase in IgA (3.3%), an elevated level of IgG (2.2%) and a concomitant increase in IgM and IgA (1.1%), respectively. Seven of the patients (8.1%) had oligo-/monoclonal gammopathy. The gammopathies included all major immunoglobulin isotypes. Chemotherapeutic intervention in 2 cases precipitated the emergence of new clones within a matter of weeks. Further investigation of oligo-/monoclonal gammopathies in these patients may lead to a clearer understanding of the clinical course and provide further insight into the underlying mechanisms of B-cell abnormalities in ataxia-telangiectasia.

The genetic defect in ataxia-telangiectasia

The autosomal recessive human disorder ataxia-telangiectasia (A-T) was first described as a separate disease entity 40 years ago. It is a multisystem disease characterized by progressive cerebellar ataxia, oculocutaneous telangiectasia, radiosensitivity, predisposition to lymphoid malignancies and immunodeficiency, with defects in both cellular and humoral immunity. The pleiotropic nature of the clinical and cellular phenotype suggests that the gene product involved is important in maintaining stability of the genome but also plays a more general role in signal transduction. The chromosomal instability and radiosensitivity so characteristic of this disease appear to be related to defective activation of cell cycle checkpoints. Greater insight into the nature of the defect in A-T has been provided by the recent identification, by positional cloning, of the responsible gene, ATM. The ATM gene is related to a family of genes involved in cellular responses to DNA damage and/or cell cycle control. These genes encode large proteins containing a phosphatidylinositol 3-kinase domain, some of which have protein kinase activity. The mutations causing A-T completely inactivate or eliminate the ATM protein. This protein has been detected and localized to different subcellular compartments.

Ataxia-without-telangiectasia. Progressive multisystem degeneration with IgE deficiency and chromosomal instability

Three of five siblings developed a progressive neurological disorder during infancy or early childhood characterized by cerebellar ataxia, choreoathetosis and peripheral neuropathy. Immunological studies revealed a marked selective deficiency of serum IgE in all three affected siblings. There was evidence of chromosomal instability in the three affected siblings and in one of the parents. One of the affected siblings also developed acute lymphoblastic leukaemia. In spite of many resemblances, this syndrome differs from classical or complete ataxia telangiectasia in that oculocutaneous telangiectases were lacking, the serum IgA and alpha-fetoprotein levels in this family were normal, there was no gonadal dysgenesis, and the cytogenetic findings were atypical.

Common and uncommon cutaneous findings in patients with ataxia-telangiectasia

This series describes some common and uncommon cutaneous findings in twelve patients with ataxia-telangiectasia (A-T). All patients had the characteristic telangiectasia as described previously. However, the telangiectases did not conform to a classic photodistribution . Our series did include one patient with a pathologic reaction to light-simulating hydroa aestivale or vacciniforme . In addition, there were three patients with acanthosis nigricans in two unrelated families. Vitiligo, impetigo, recurrent herpetic gingivostomatitis, hirsutism, lipoatrophy, gray hair, progeroid changes and hyper- and hypopigmented macules were noted in our patients. Many of our patients had one or more caf'e au lait like-lesions in a dermatomal distribution. In addition, several of the family members showed one or more café au lait-like lesions, suggesting the possibility that this finding may represent a phenotypic expression in the skin of carriers of this cancer-prone syndrome.

Chromosomal instability in ataxia telangiectasia

We have examined various aspects of lymphocyte chromosomal instability in three families comprised of five individuals affected with ataxiatelangiectasia (AT), their obligate heterozygous parents, and their unaffected sibs. We found that neither baseline sister chromatid exchanges (SCEs) nor mitomycin-C-induced increments in SCEs showed any significant differences among family members or between AT heterozygotes or homozygotes. Chromosome breakage in first-division metaphases was found to be moderately elevated in three of the five AT homozygotes (range 1-12%); breakage in the six AT obligate heterozygotes was within normal limits (0-4%). Analysis of Giemsa-banded metaphases indicated the presence of a clone bearing a paracentric inversion of chromosome #14 in addition to other chromosome #14 abnormalities in one AT homozygote. The same inversion was also found in this individual's affected sister and his obligate heterozygous father. A discussion regarding the relationship of the specificity of breakage and reunion of bands q12 and q23 on chromosome #14 and the high incidence of malignancy in AT is included.

Disseminated Herpes simplex virus infection in ataxia-telangiectasia

The clinical and pathological features are described in a child with ataxia-telangiectasia, complicated by fatal disseminated herpes simplex virus infection. Herpes simplex virus was isolated from the patient's blood, and the histopathological findings in the skin, liver and adrenals were consistent with herpes simplex virus infection. The patient had a combined immune deficiency state, as a part of the ataxia-telangiectasia syndrome. She had imparied cellular immune response to herpes simplex virus and developed no antibodies against the virus. To our knowledge, this is the first fatal case of disseminated herpes simplex virus infection in ataxiatelangiectasia.

Extreme insulin resistance in ataxia telangiectasia: defect in affinity of insulin receptors

The syndrome of ataxia telangiectasia is associated with glucose intolerance and insulin resistance. We examined the status of insulin receptors on circulating monocytes and on cultured fibroblasts from two siblings with ataxia telangiectasia and severe insulin resistance. 125I-insulin binding to monocytes of the two patients consistently demonstrated an 80 to 85 per cent decrease in receptor affinity. In contrast, the defect in receptor affinity was not expressed on the patients' cultured fibroblasts or on monocytes or fibroblasts obtained from unaffected family members. Whole plasma and immunoglobulin-enriched fractions of plasma from the patients inhibited the normal binding of insulin to its receptors on cultured human lymphocytes (IM -9 line) and on human placental membranes. We conclude that the insulin resistance in the two siblings with ataxia telangiectasia was associated with defects in the affinity of the receptors for insulin, probably caused by circulating inhibitors of insulin binding.

A study of serum IgA levels in children undergoing tonsillectomy

Earlier work has suggested that up to 25% of children undergoing tonsillectomy because of recurrent sore throats are relatively deficient in IgA immunoglobulin and that they do less well after the operation than 'normal' children. Measurements of serum immunoglobulin levels were carried out in 96 children undergoing tonsillectomy for recurrent sore throats. Levels of IgA, IgM and IgG were found to be similar to those in healthy children, 7-29% of those studied had 'low' IgA serum levels. There was a significant relationship between serum IgA levels and the age of the child. No relationship could be established between IgA levels and pre- or postoperative clinicaal state of the children. Low IgA serum levels are probably the result of delayed immunological maturation rather than a true immunodeficient state. IgA estimations, therefore, have no bearing on selection for operation or the prognosis after operation.

Abnormalities in sensory and mixed evoked potentials in ataxia-telangiectasia

Electromography, motor, sensory and mixed nerve conduction velocity, and H reflex were studied in four patients with ataxia-telangiectasia. The earliest and most striking electrophysiologial finding was the reduced amplitude of evoked nerve potentials. In the oldest patient, findings suggestive of spinal atrophy and mild reduction of the motor and sensory nerve conduction velocities were found. Reduced amplitude in the evoked nerve potentials can be observed without clinical evidence of peripheral neuropathy. Electrophysiological abnormalities are more severe in older than in young patients. Sural nerve biopsy in one patient showed mild changes: loss of the largest myelinated fibres and demyelination of some fibres. The ratio between maximum conduction velocity of the sural nerve and the diameter of the largest fibres was in the lower limits of the normal range. The resemblance between electrophysiological abnormalities in Friedreich's ataxia and ataxia-telangiectasia is discussed.

Immunoglobulin abnormalities in epileptic patients treated with diphenylhydantoin

An immunologic study was made on 170 epileptic patients treated with antiepileptic drugs. The most noteworthy finding was that the serum IgA was decreased in 22 patients, and an IgA deficiency noticed in 12 of them. The blastic transformation rate of lymphocytes in PHA-containing cultures appeared low in seven out of 12 patients. Other findings included decreased serum IgM and IgG in some patients. These abnormalities were not encountered in epileptic patients taking no anti-epileptic drugs. Therefore, they could be considered as the side effects of antiepileptic drugs. In all patients manifesting these abnormalities, diphenylhydantoin was used in common. It was surmised that the above-mentioned immunologic abnormalities caused by anti-epileptic drugs, especially diphenylhydantoin, had resulted from disorders of the antibody producing organs in the bone marrow-thymus-lymphatic system.

Protein patterns of cerebrospinal fluid in hereditary ataxias and hereditary spastic paraplegia

The CSF findings in hereditary ataxias and allief disorders have hitherto mostly been reported as normal if one excludes Refsum's syndrome. The CSF-protein patterns found on isoelectric focusing and quantitative paper electrophoresis were studied in 12 patients with hereditary ataxias and hereditary spastic paraplegia. Using a recently-developed technique of isoelectric focusing of CSF-proteins in flat beds of polyacrylamide gel, the authors could show abnormal CSF-protein patterns in all but 1 of the present cases. The aberrant CSF-protein patterns found showed differences between the syndromes studied. Two unique patterns with conspicuous fractions in the acid range were observed in patients with Marie-Sanger-Brown's ataxia (mother and daughter) and Holmes' ataxia. A third CSF-protein pattern was found in a sibship with Friedreich's ataxia including a double fraction in the acid region (pI 5.9-6.1) in all 4 subjects and a highly alkaline fraction (HAF) with pI about 9.3, in 3 of them. Similar acid fractions (pI 5.9-6.1) were also detected in 3 of 4 patients with hereditary spastic paraplegia, a brother and sister showing a very similar CSF-protein pattern. Double fractions with pI 5.9-6.1 and/or HAF may also occur in other neurological diseases, mostly, however, associated with other distinctive features of their CSF-protein patterns. A possibility in the future of distinguishing hereditary CNS-diseases by examination of the CSF-protein pattern is suggested.

A hereditary immunoglobulin A abnormality: absence of light-heavy-chain assembly. Study of immunoglobulin synthesis in tonsillar cells

A new immunoglobulin A abnormality, absence of assembly of alpha-chain and light-chain, was found in an adult female suffering from recurrent upper respiratory infection and tonsillitis since childhood, but otherwise healthy. The IgA abnormality was manifest in her serum by the presence of free alpha-chains, in her saliva by the presence of alpha-chains bound to secretory piece, and in her urine by the presence of free alpha-chains and free light-chains. The serum IgG and IgM were found to be complete, containing both heavy-chains and light-chains. Evidence for this immunoglobulin A abnormality was also found in the proposita's mother and elder son, demonstrating it to be a hereditary disorder. Studies performed with patient's tonsillar cells in short-term culture, using amino acids-(14)C, revealed synthesis and secretion of both free alpha-chains and free light-chains, in addition to synthesis and secretion of normally assembled IgG and IgM.

Immunoglobulin metabolism in ataxia telangiectasia

Immunoglobulin metabolism has been studied in five patients with ataxia telangiectasia and in control subjects. Serum IgG levels were normal, increased, or decreased, reflecting normal, increased, or decreased synthetic rates, respectively. Serum IgM concentration was normal in three cases and slightly elevated in two cases. IgM turnover studies in the three cases with normal serum IgM levels showed normal IgM synthetic and catabolic rates. None of the five patients with ataxia telangiectasia had detectable serum IgA, and the maximum IgA synthetic rates possible for these patients were 0.3-10% of the normal mean synthetic rate (24 +/- 15 mg/kg per day) of 12 control individuals. Three of the patients had normal IgA fractional catabolic rates: 22% of the intravascular pool per day vs. 25 +/- 4% in controls. In two patients, fractional catabolic rates 4 and 20 times normal were found. In these cases, metabolic turnover, in vitro precipitation, radioimmunoelectrophoresis, and (or) the C'la fixation and transfer test provided evidence for the presence of a circulating antibody directed against IgA causing immune elimination of the molecule. These studies suggest that therapy with exogenous IgA may not be possible in some patients with ataxia telangiectasia or in other subjects with dysgammaglobulinemia.