Considerations for radiotherapy in Bloom Syndrome: A case series.

Bloom Syndrome (BS) is a genetic DNA repair disorder, caused by mutations in the BLM gene. The clinical phenotype includes growth retardation, immunodeficiency and a strong predisposition to different types of malignancies. Treatment of malignancies in BS patients with radiotherapy or chemotherapy is believed to be associated with increased toxicity, but clinical and laboratory data are lacking. We collected clinical data of two Dutch BS patients with solid tumors. Both were treated with radiotherapy before the diagnosis BS was made and tolerated this treatment well. In addition, we collected fibroblasts from BS patients to perform in vitro clonogenic survival assays to determine radiosensitivity. BS fibroblasts showed less radiosensitivity than the severely radiosensitive Artemis fibroblasts. Moreover, studies of double strand break kinetics by counting 53BP1 foci after irradiation showed similar patterns compared to healthy controls. In combination, the clinical cases and laboratory experiments are valuable information in the discussion whether radiotherapy is absolutely contraindicated in BS, which is the Case in other DNA repair syndromes like Ataxia Telangiectasia and Artemis.

Early diagnosis of ataxia telangiectasia in the neonatal phase: a parents' perspective.

Ataxia telangiectasia (A-T) is a severe neurodegenerative disorder with variable immunodeficiency. Together with the Dutch A-T community, we investigated the opinion of A-T parents on an early A-T diagnosis in the asymptomatic phase of the disease. During an annual national meeting for A-T patients and families, the topic of an early A-T diagnosis was discussed in relation to the recent introduction of neonatal screening for severe combined immunodeficiency (SCID) in the Netherlands. Based on the discussion, individual arguments were identified and processed into a questionnaire, which was sent out to 64 A-T parents (32 families). Arguments included were insecurity to diagnosis, possible medical advantages, appropriate genetic counseling and family planning, loss of "golden" year(s), and early cancer screening for parents. The response rate was 55% (n = 35 parents). Twenty-six (74%) parents felt that the advantages of an early diagnosis outweighed the disadvantages, five parents thought that the disadvantages would outweigh the advantages (14%), and four parents did not indicate a preference.Conclusion: The majority of parents of a child with A-T would have preferred an early diagnosis during the asymptomatic phase of the disease, because the uncertainty during the diagnostic process had had a major impact on their lives. In addition, the knowledge of being carriers of an ATM gene mutation influenced decisions about family planning. Parents who opposed against an early diagnosis emphasized the joy of having a seemingly healthy child until diagnosis.What is Known:• Ataxia telangiectasia (A-T) is a devastating DNA repair disorder with a huge impact on quality of life of patients and their parents.• Patients with A-T may incidentally be identified at birth as the consequence of neonatal screening for severe combined immunodeficiency (SCID).What is New:• The majority of Dutch parents of A-T patients (74%) would have preferred an early diagnosis of their child in the asymptomatic phase of the disease.• Major arguments for an early A-T diagnosis were (1) the experienced insecurity in diagnostic trajectories and its impact on families and (2) the knowledge of being ATM mutation carriers when deciding about family planning. An argument against an early diagnosis is losing the joy of having a seemingly healthy child until diagnosis.

Telangiectasias in Ataxia Telangiectasia: Clinical significance, role of ATM deficiency and potential pathophysiological mechanisms.

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.

Telangiectasias: Small lesions referring to serious disorders.

Telangiectasias are prominent small vessels (venules, capillaries or arterioles) that are visible as small red-purple focal lesions in the skin and mucous membranes. They can serve as a cutaneous marker for a number of primary (mostly hereditary) disorders and they can be secondary to other (systemic) diseases. Patients with telangiectasias are seen by general health practitioners, pediatricians, (pediatric) neurologists, dermatologists, and ophthalmologists. In this article we give an overview of the different disorders in which telangiectasias are a prominent feature, focusing on neurocutaneous disorders in which they serve as a marker for establishing the right diagnosis. The pattern of distribution of the telangiectasias, their age of onset and associated features are helpful to distinguish between the different disorders.

Expanding the mutation spectrum in ICF syndrome: Evidence for a gender bias in ICF2.

BACKGROUND: Immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome is a rare, genetically heterogeneous, autosomal recessive disorder. Patients suffer from recurrent infections caused by reduced levels or absence of serum immunoglobulins. Genetically, 4 subtypes of ICF syndrome have been identified to date: ICF1 (DNMT3B mutations), ICF2 (ZBTB24 mutations), ICF3 (CDCA7 mutations), and ICF4 (HELLS mutations). AIM: To study the mutation spectrum in ICF syndrome. MATERIALS AND METHODS: Genetic studies were performed in peripheral blood lymphocyte DNA from suspected ICF patients and family members. RESULTS: We describe 7 ICF1 patients and 6 novel missense mutations in DNMT3B, affecting highly conserved residues in the catalytic domain. We also describe 5 new ICF2 patients, one of them carrying a homozygous deletion of the complete ZBTB24 locus. In a meta-analysis of all published ICF cases, we observed a gender bias in ICF2 with 79% male patients. DISCUSSION: The biallelic deletion of ZBTB24 provides strong support for the hypothesis that most ICF2 patients suffer from a ZBTB24 loss of function mechanism and confirms that complete absence of ZBTB24 is compatible with human life. This is in contrast to the observed early embryonic lethality in mice lacking functional Zbtb24. The observed gender bias seems to be restricted to ICF2 as it is not observed in the ICF1 cohort. CONCLUSION: Our study expands the mutation spectrum in ICF syndrome and supports that DNMT3B and ZBTB24 are the most common disease genes.

Health risks for ataxia-telangiectasia mutated heterozygotes: a systematic review, meta-analysis and evidence-based guideline.

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.

Alpha-fetoprotein, a fascinating protein and biomarker in neurology.

Alpha-fetoprotein (AFP) is present in fetal serum in concentrations up to 5,000,000 µg/l. After birth, AFP gene expression is turned down with a subsequent fall of the serum concentrations of this albumin-like protein to 'adult values' of circa 0.5-15 µg/l from the age of 2 years onwards. Irrespective of its assumed important functions, individuals with AFP deficiency appear fully healthy. The other way around, the presence of AFP in the circulation after the first years of life doesn't seem to harm, since individuals with 'hereditary persistence of AFP' are also without clinical abnormalities. During pregnancy, AFP (in maternal serum) has long been recognized as a marker for congenital anomalies of the fetus. Equally well known is AFP as biomarker for hepatocellular carcinoma and some other malignancies. There are at least four neurodegenerative disorders, all inherited as autosomal recessive traits and characterized by the presence of cerebellar ataxia, abnormal ocular movements, and neuropathy, for which an elevated concentration of serum AFP is an important diagnostic biomarker. The availability of a reliable biomarker is not only important during screening or diagnostic processes, but is also relevant for objective follow-up during (future) therapeutic interventions.

Cutaneous granulomas in ataxia telangiectasia and other primary immunodeficiencies: reflection of inappropriate immune regulation?

BACKGROUND: Non-infective cutaneous granulomas with unknown pathogenesis occur in various primary immunodeficiencies (PIDs) including ataxia telangiectasia (A-T). OBJECTIVE: To find a common immunological denominator in these cutaneous granulomas. METHODS: The dermatological and immunological features of 4 patients with A-T and cutaneous granulomas were described. The literature on skin granulomas in A-T and in other PIDs is reviewed. RESULTS: All 4 A-T patients had progressive granulomas on their limbs and showed decreased IgG and IgA concentrations with normal IgM levels. They had a marked decrease in B cells and naïve T cells coinciding with the appearance of the cutaneous granulomas. Similar B- and T-cell abnormalities were described in patients with other PIDs with skin granulomas. CONCLUSIONS: We hypothesize that the pathogenesis of these skin granulomas is related to immune dysregulation of macrophages due to the absence of naïve T cells with an appropriate T-cell receptor repertoire and the unopposed activity of γδ T cells and/or natural killer cells.

Lymphoid tumours and breast cancer in ataxia telangiectasia; substantial protective effect of residual ATM kinase activity against childhood tumours.

BACKGROUND: Immunodeficiency in ataxia telangiectasia (A-T) is less severe in patients expressing some mutant or normal ATM kinase activity. We, therefore, determined whether expression of residual ATM kinase activity also protected against tumour development in A-T. METHODS: From a total of 296 consecutive genetically confirmed A-T patients from the British Isles and the Netherlands, we identified 66 patients who developed a malignant tumour; 47 lymphoid tumours and 19 non-lymphoid tumours were diagnosed. We determined their ATM mutations, and whether cells from these patients expressed any ATM with residual ATM kinase activity. RESULTS: In childhood, total absence of ATM kinase activity was associated, almost exclusively, with development of lymphoid tumours. There was an overwhelming preponderance of tumours in patients <16 years without kinase activity compared with those with some residual activity, consistent with a substantial protective effect of residual ATM kinase activity against tumour development in childhood. In addition, the presence of eight breast cancers in A-T patients, a 30-fold increased risk, establishes breast cancer as part of the A-T phenotype. CONCLUSION: Overall, a spectrum of tumour types is associated with A-T, consistent with involvement of ATM in different mechanisms of tumour formation. Tumour type was influenced by ATM allelic heterogeneity, residual ATM kinase activity and age.

Artemis splice defects cause atypical SCID and can be restored in vitro by an antisense oligonucleotide.

Artemis deficiency is known to result in classical T-B- severe combined immunodeficiency (SCID) in case of Artemis null mutations, or Omenn's syndrome in case of hypomorphic mutations in the Artemis gene. We describe two unrelated patients with a relatively mild clinical T-B- SCID phenotype, caused by different homozygous Artemis splice-site mutations. The splice-site mutations concern either dysfunction of a 5' splice-site or an intronic point mutation creating a novel 3' splice-site, resulting in mutated Artemis protein with residual activity or low levels of wild type (WT) Artemis transcripts. During the first 10 years of life, the patients suffered from recurrent infections necessitating antibiotic prophylaxis and intravenous immunoglobulins. Both mutations resulted in increased ionizing radiation sensitivity and insufficient variable, diversity and joining (V(D)J) recombination, causing B-lymphopenia and exhaustion of the naive T-cell compartment. The patient with the novel 3' splice-site had progressive granulomatous skin lesions, which disappeared after stem cell transplantation (SCT). We showed that an alternative approach to SCT can, in principle, be used in this case; an antisense oligonucleotide (AON) covering the intronic mutation restored WT Artemis transcript levels and non-homologous end-joining pathway activity in the patient fibroblasts.

Clinical spectrum of ataxia-telangiectasia in adulthood.

OBJECTIVE: To describe the phenotype of adult patients with variant and classic ataxia-telangiectasia (A-T), to raise the degree of clinical suspicion for the diagnosis variant A-T, and to assess a genotype-phenotype relationship for mutations in the ATM gene. METHODS: Retrospective analysis of the clinical characteristics and course of disease in 13 adult patients with variant A-T of 9 families and 6 unrelated adults with classic A-T and mutation analysis of the ATM gene and measurements of ATM protein expression and kinase activity. RESULTS: Patients with variant A-T were only correctly diagnosed in adulthood. They often presented with extrapyramidal symptoms in childhood, whereas cerebellar ataxia appeared later. Four patients with variant A-T developed a malignancy. Patients with classic and variant A-T had elevated serum alpha-fetoprotein levels and chromosome 7/14 rearrangements. The mildest variant A-T phenotype was associated with missense mutations in the ATM gene that resulted in expression of some residual ATM protein with kinase activity. Two splicing mutations, c.331 + 5G>A and c.496 + 5G>A, caused a more severe variant A-T phenotype. The splicing mutation c.331 + 5G>A resulted in less ATM protein and kinase activity than the missense mutations. CONCLUSIONS: Ataxia-telangiectasia (A-T) should be considered in patients with unexplained extrapyramidal symptoms. Early diagnosis is important given the increased risk of malignancies and the higher risk for side effects of subsequent cancer treatment. Measurement of serum alpha-fetoprotein and chromosomal instability precipitates the correct diagnosis. There is a clear genotype-phenotype relation for A-T, since the severity of the phenotype depends on the amount of residual kinase activity as determined by the genotype.

Ataxia-telangiectasia patients presenting with hyper-IgM syndrome.

Ataxia-telangiectasia (A-T) is characterised by progressive neurological abnormalities, oculocutaneous telangiectasias and immunodeficiency (decreased serum IgG subclass and/or IgA levels and lymphopenia). However, 10% of A-T patients present with decreased serum IgG and IgA with normal or raised IgM levels. As cerebellar ataxia and oculocutaneous telangiectasias are not present at very young age, these patients are often erroneously diagnosed as hyper IgM syndrome (HIGM). Eight patients with A-T, showing serum Ig levels suggestive of HIGM on first presentation, are described. All had decreased numbers of T lymphocytes, unusual in HIGM. The diagnosis A-T was confirmed by raised alpha-fetoprotein levels in all patients. To prevent mistaking A-T patients for HIGM it is proposed to add DNA repair disorders as a possible cause of HIGM.

Clinical spectrum of immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome).

BACKGROUND: Immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome) is a rare autosomal recessive disease characterised by facial dysmorphism, immunoglobulin deficiency and branching of chromosomes 1, 9 and 16 after PHA stimulation of lymphocytes. Hypomethylation of DNA of a small fraction of the genome is an unusual feature of ICF patients which is explained by mutations in the DNA methyltransferase gene DNMT3B in some, but not all, ICF patients. OBJECTIVE: To obtain a comprehensive description of the clinical features of this syndrome as well as genotype-phenotype correlations in ICF patients. METHODS: Data on ICF patients were obtained by literature search and additional information by means of questionnaires to corresponding authors. RESULTS AND CONCLUSIONS: 45 patients all with proven centromeric instability were included in this study. Facial dysmorphism was found to be a common characteristic (n = 41/42), especially epicanthic folds, hypertelorism, flat nasal bridge and low set ears. Hypo- or agammaglobulinaemia was demonstrated in nearly all patients (n = 39/44). Opportunistic infections were seen in several patients, pointing to a T cell dysfunction. Haematological malignancy was documented in two patients. Life expectancy of ICF patients is poor, especially those with severe infections in infancy or chronic gastrointestinal problems and failure to thrive. Early diagnosis of ICF is important since early introduction of immunoglobulin supplementation can improve the course of the disease. Allogeneic stem cell transplantation should be considered as a therapeutic option in patients with severe infections or failure to thrive. Only 19 of 34 patients showed mutations in DNMT3B, suggesting genetic heterogeneity. No genotype-phenotype correlation was found between patients with and without DNMT3B mutations.

Reversible hypogammaglobulinaemia.

In this report we present four patients with reversible hypogammaglobulinaemia who required immunoglobulin substitution for several years. One patient had documented systemic lupus erythematosus (SLE), the other three patients had primary hypogammaglobulinaemia without known cause. Whereas the cessation of azathioprine therapy may have contributed to the recovery in the patient with SLE, the restoration of the immunoglobulin production in the other three patients occurred spontaneously. All four patients were IgA deficient when the hypogammaglobulinaemia was first detected and remained so after IgM and IgG production had recovered. Two of the three patients who also had anti-IgA antibodies started to produce anti-IgA again after stopping the immunoglobulin substitution. We conclude that recovery of hypogammaglobulinaemia is possible but rare. When recovery is suspected, we recommend that immunoglobulin substitution is stopped and the antibody response to vaccination is tested.

Neuromuscular abnormalities in ataxia telangiectasia: a clinical, electrophysiological and muscle ultrasound study.

Thirteen classical ataxia telangiectasia (A-T) patients, varying in age from 1 to 25 years, were studied clinically, electrophysiologically as well as by muscle ultrasound to chart the development and spectrum of neuromuscular abnormalities in A-T. The most prominent finding was a progressive axonal sensorimotor polyneuropathy, apparent by electromyography and muscle ultrasound from the age of 8 years and becoming clinically discernible around 12 years of age. Before the age of 8 years decreased tendon reflexes and slightly slowed sensory nerve conduction velocities could already be observed. With routine electrophysiological techniques the severe polyneuropathy precludes conclusions about the presence of anterior horn cell loss in older patients.

Hypomethylation is restricted to the D4Z4 repeat array in phenotypic FSHD.

BACKGROUND: Patients with facioscapulohumeral muscular dystrophy (FSHD) show a contraction of the D4Z4 repeat array in the subtelomere of chromosome 4q. This D4Z4 contraction is associated with significant allele-specific hypomethylation of the repeat. Hypomethylation of D4Z4 is also observed in patients with phenotypic FSHD without contraction of D4Z4 and in patients with the immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome, an unrelated disease that does not present with muscular dystrophy and is in part caused by DNMT3B mutations. METHODS: In order to identify the gene defect and to find the pathogenetic epigenetic pathway in phenotypic FSHD, we have aimed to identify the differences and commonalities in phenotypic FSHD and ICF by 1) investigation of DNA methylation of non-D4Z4 repeat arrays, 2) analysis of mitogen-stimulated lymphocytes to detect pericentromeric abnormalities involving chromosomes 1, 9, and 16, 3) determination of IgA, IgG, and IgM levels, and 4) mutational analysis of candidate genes to identify a second disease locus involved in the pathogenesis of phenotypic FSHD. RESULTS: Our results do not show epigenetic or phenotypic commonalities between phenotypic FSHD and ICF other than the earlier observed D4Z4 hypomethylation. We could not identify any mutations in the candidate genes tested for. CONCLUSION: Our data suggest that in phenotypic FSHD hypomethylation is restricted to D4Z4 and that phenotypic FSHD and ICF do not share a defect in the same molecular pathway.

Distal spinal muscular atrophy as a major feature in adult-onset ataxia telangiectasia.

The authors report four adult-onset ataxia telangiectasia (AT) patients belonging to two families lacking pronounced cerebellar ataxia but displaying distal spinal muscular atrophy. AT was proven by genetic studies showing ATM mutations and a reduced level of ATM. ATM activity, as measured by phosphorylation of p53, was close to normal, indicating that the p53 response is not the only factor in preventing neural damage in anterior horn cells in AT.

Critical aneurysmal dilatation of the thoracic aorta in young adolescents with variant hyperimmunoglobulin E syndrome.

The autosomal-dominant (AD) form of the hyperimmunoglobulin E syndrome (HIES) has been described as a multisystem disorder including immune, skeletal and dental abnormalities. Recently, the evaluation of patients from families in which HIES was inherited in a manner more consistent with autosomal-recessive (AR) inheritance, showed that AR-HIES is a clinically distinct disease entity. In addition to classical immunologic findings of AD-HIES, the AR form presents with severe recurrent fungal and viral infections with herpes zoster, herpes simplex and characteristic mollusca contagiosa. Furthermore, cerebral vascular sequelae, including vasculitis, infarction and haemorrhage were noted. In this report, we describe the clinical picture of two patients who showed remarkable resemblance to the description of AR-HIES, but also developed fatal aneurysmal dilatation of the thoracic aorta in adolescence. This finding may further consummate the clinical picture of AR-HIES and emphasize the possibility to develop early aortitis, most likely preceding the critical aneurysm formation at older age. This process should be anticipated during childhood in cases with AR-HIES.