The fragile X-associated tremor ataxia syndrome (FXTAS) in Indonesia.

Fragile X-associated disorders caused by the premutation of the FMR1 gene, includes the fragile X-associated tremor/ataxia syndrome (FXTAS). FXTAS affects more than 40% of premutation males over the age of 50 and 75% over the age of 80. FMR1 molecular analysis was done using PCR and confirmed by Southern Blot. Three premutation males were diagnosed FXTAS using quantification based on the standard neurological examination. Cognitive impairment was assessed using Raven and WAIS-R test. MRI was done to identify the middle cerebellar peduncle (MCP) sign, white matter disease and/or cerebral atrophy. Three cases of FXTAS are identified, of five individuals older than 50 years in one family tree two met criteria for definite FXTAS and the third with sub-clinical symptoms, although cognitive and radiological criteria are met. These cases are the first identified FXTAS cases in rural Indonesia. In addition with lack of routine medical follow-up, complications of FXTAS, such as hypertension may go unrecognized and untreated, which may further exacerbate the central nervous system (CNS) findings of FXTAS.

Familial Kleefstra syndrome due to maternal somatic mosaicism for interstitial 9q34.3 microdeletions.

The Kleefstra syndrome (Online Mendelian Inheritance in Man 607001) is caused by a submicroscopic 9q34.3 deletion or by intragenic euchromatin histone methyl transferase 1 (EHMT1) mutations. So far only de novo occurrence of mutations has been reported, whereas 9q34.3 deletions can be either de novo or caused by complex chromosomal rearrangements or translocations. Here we give the first descriptions of affected parent-to-child transmission of Kleefstra syndrome caused by small interstitial deletions, approximately 200 kb, involving part of the EHMT1 gene. Additional genome-wide array studies in the parents showed the presence of similar deletions in both mothers who only had mild learning difficulties and minor facial characteristics suggesting either variable clinical expression or somatic mosaicism for these deletions. Further studies showed only one of the maternal deletions resulted in significantly quantitative differences in signal intensity on the array between the mother and her child. But by investigating different tissues with additional fluorescent in situ hybridization (FISH) and multiplex ligation-dependent probe amplification (MLPA) analyses, we confirmed somatic mosaicism in both mothers. Careful clinical and cytogenetic assessments of parents of an affected proband with an (interstitial) 9q34.3 microdeletion are merited for accurate estimation of recurrence risk.

Further clinical and molecular delineation of the 9q subtelomeric deletion syndrome supports a major contribution of EHMT1 haploinsufficiency to the core phenotype.

BACKGROUND: The 9q subtelomeric deletion syndrome (9qSTDS) is clinically characterised by moderate to severe mental retardation, childhood hypotonia and facial dysmorphisms. In addition, congenital heart defects, urogenital defects, epilepsy and behavioural problems are frequently observed. The syndrome can be either caused by a submicroscopic 9q34.3 deletion or by intragenic EHMT1 mutations leading to haploinsufficiency of the EHMT1 gene. So far it has not been established if and to what extent other genes in the 9q34.3 region contribute to the phenotype observed in deletion cases. This study reports the largest cohort of 9qSTDS cases so far. METHODS AND RESULTS: By a multiplex ligation dependent probe amplification (MLPA) approach, the authors identified and characterised 16 novel submicroscopic 9q deletions. Direct sequence analysis of the EHMT1 gene in 24 patients exhibiting the 9qSTD phenotype without such deletion identified six patients with an intragenic EHMT1 mutation. Five of these mutations predict a premature termination codon whereas one mutation gives rise to an amino acid substitution in a conserved domain of the protein. CONCLUSIONS: The data do not provide any evidence for phenotype-genotype correlations between size of the deletions or type of mutations and severity of clinical features. Therefore, the authors confirm the EHMT1 gene to be the major determinant of the 9qSTDS phenotype. Interestingly, five of six patients who had reached adulthood had developed severe psychiatric pathology, which may indicate that EHMT1 haploinsufficiency is associated with neurodegeneration in addition to neurodevelopmental defect.

Further delineation of the 15q13 microdeletion and duplication syndromes: a clinical spectrum varying from non-pathogenic to a severe outcome.

BACKGROUND: Recurrent 15q13.3 microdeletions were recently identified with identical proximal (BP4) and distal (BP5) breakpoints and associated with mild to moderate mental retardation and epilepsy. METHODS: To assess further the clinical implications of this novel 15q13.3 microdeletion syndrome, 18 new probands with a deletion were molecularly and clinically characterised. In addition, we evaluated the characteristics of a family with a more proximal deletion between BP3 and BP4. Finally, four patients with a duplication in the BP3-BP4-BP5 region were included in this study to ascertain the clinical significance of duplications in this region. RESULTS: The 15q13.3 microdeletion in our series was associated with a highly variable intra- and inter-familial phenotype. At least 11 of the 18 deletions identified were inherited. Moreover, 7 of 10 siblings from four different families also had this deletion: one had a mild developmental delay, four had only learning problems during childhood, but functioned well in daily life as adults, whereas the other two had no learning problems at all. In contrast to previous findings, seizures were not a common feature in our series (only 2 of 17 living probands). Three patients with deletions had cardiac defects and deletion of the KLF13 gene, located in the critical region, may contribute to these abnormalities. The limited data from the single family with the more proximal BP3-BP4 deletion suggest this deletion may have little clinical significance. Patients with duplications of the BP3-BP4-BP5 region did not share a recognisable phenotype, but psychiatric disease was noted in 2 of 4 patients. CONCLUSIONS: Overall, our findings broaden the phenotypic spectrum associated with 15q13.3 deletions and suggest that, in some individuals, deletion of 15q13.3 is not sufficient to cause disease. The existence of microdeletion syndromes, associated with an unpredictable and variable phenotypic outcome, will pose the clinician with diagnostic difficulties and challenge the commonly used paradigm in the diagnostic setting that aberrations inherited from a phenotypically normal parent are usually without clinical consequences.

Clinical and molecular characteristics of 1qter microdeletion syndrome: delineating a critical region for corpus callosum agenesis/hypogenesis.

BACKGROUND: Patients with a microscopically visible deletion of the distal part of the long arm of chromosome 1 have a recognisable phenotype, including mental retardation, microcephaly, growth retardation, a distinct facial appearance and various midline defects including corpus callosum abnormalities, cardiac, gastro-oesophageal and urogenital defects, as well as various central nervous system anomalies. Patients with a submicroscopic, subtelomeric 1qter deletion have a similar phenotype, suggesting that the main phenotype of these patients is caused by haploinsufficiency of genes in this region. OBJECTIVE: To describe the clinical presentation of 13 new patients with a submicroscopic deletion of 1q43q44, of which nine were interstitial, and to report on the molecular characterisation of the deletion size. RESULTS AND CONCLUSIONS: The clinical presentation of these patients has clear similarities with previously reported cases with a terminal 1q deletion. Corpus callosum abnormalities were present in 10 of our patients. The AKT3 gene has been reported as an important candidate gene causing this abnormality. However, through detailed molecular analysis of the deletion sizes in our patient cohort, we were able to delineate the critical region for corpus callosum abnormalities to a 360 kb genomic segment which contains four possible candidate genes, but excluding the AKT3 gene.

Screening for subtelomeric rearrangements in 210 patients with unexplained mental retardation using multiplex ligation dependent probe amplification (MLPA).

BACKGROUND: Subtelomeric rearrangements contribute to idiopathic mental retardation and human malformations, sometimes as distinct mental retardation syndromes. However, for most subtelomeric defects a characteristic clinical phenotype remains to be elucidated. OBJECTIVE: To screen for submicroscopic subtelomeric aberrations using multiplex ligation dependent probe amplification (MLPA). METHODS: 210 individuals with unexplained mental retardation were studied. A new set of subtelomeric probes, the SALSA P036 human telomere test kit, was used. RESULTS: A subtelomeric aberration was identified in 14 patients (6.7%) (10 deletions and four duplications). Five deletions were de novo; four were inherited from phenotypically normal parents, suggesting that these were polymorphisms. For one deletion, DNA samples of the parents were not available. Two de novo submicroscopic duplications were detected (dup 5qter, dup 12pter), while the other duplications (dup 18qter and dup 22qter) were inherited from phenotypically similarly affected parents. All clinically relevant aberrations (de novo or inherited from similarly affected parents) occurred in patients with a clinical score of >or=3 using an established checklist for subtelomeric rearrangements. Testing of patients with a clinical score of >or=3 increased the diagnostic yield twofold to 12.4%. Abnormalities with clinical relevance occurred in 6.3%, 5.1%, and 1.7% of mildly, moderately, and severely retarded patients, respectively, indicating that testing for subtelomeric aberrations among mildly retarded individuals is necessary. CONCLUSIONS: The value of MLPA is confirmed. Subtelomeric screening can be offered to all mentally retarded patients, although clinical preselection increases the percentage of chromosomal aberrations detected. Duplications may be a more common cause of mental retardation than has been appreciated.

Update on Kleefstra Syndrome.

Kleefstra syndrome is characterized by the core phenotype of developmental delay/intellectual disability, (childhood) hypotonia and distinct facial features. The syndrome can be either caused by a microdeletion in chromosomal region 9q34.3 or by a mutation in the euchromatin histone methyltransferase 1 (EHMT1) gene. Since the early 1990s, 85 patients have been described, of which the majority had a 9q34.3 microdeletion (>85%). So far, no clear genotype-phenotype correlation could be observed by studying the clinical and molecular features of both 9q34.3 microdeletion patients and patients with an intragenic EHMT1 mutation. Thus, to further expand the genotypic and phenotypic knowledge about the syndrome, we here report 29 newly diagnosed patients, including 16 patients with a 9q34.3 microdeletion and 13 patients with an EHMT1 mutation, and review previous literature. The present findings are comparable to previous reports. In addition to our former findings and recommendations, we suggest cardiac screening during follow-up, because of the possible occurrence of cardiac arrhythmias. In addition, clinicians and caretakers should be aware of the regressive behavioral phenotype that might develop at adolescent/adult age and seems to have no clear neurological substrate, but is rather a so far unexplained neuropsychiatric feature.

Paraplegin mutations in sporadic adult-onset upper motor neuron syndromes.

OBJECTIVE: To investigate the frequency of autosomal recessive paraplegin mutations in patients with sporadic adult-onset upper motor neuron (UMN) syndromes. METHODS: We analyzed the paraplegin gene in 98 Dutch patients with a sporadic adult-onset UMN syndrome. Inclusion criteria were a progressive UMN syndrome, adult onset, duration >6 months, and negative family history. Exclusion criteria were clinical or electrophysiologic evidence of lower motor neuron loss and evidence of other causes using a predefined set of laboratory tests, including analysis of the spastin gene. RESULTS: Seven patients had homozygous or compound heterozygous pathogenic paraplegin mutations: six patients had UMN symptoms restricted to the legs and one had UMN symptoms in legs and arms. No mutations were found in the 33 patients with UMN involvement of the bulbar region. Age at onset was lower in the seven patients with paraplegin mutations (37 years, range 34-42) than in the 91 patients without mutations (51 years, range 18-77, p = 0.001). Three of the seven patients with paraplegin mutations and none of the patients without mutations developed cerebellar signs during follow-up. CONCLUSIONS: Paraplegin mutations are a frequent cause of sporadic spastic paraparesis.

Pure subtelomeric microduplications as a cause of mental retardation.

Submicroscopic subtelomeric aberrations are a common cause of mental retardation (MR). New molecular techniques allow the identification of subtelomeric microduplications, but their frequency and significance are largely unknown. We determined the frequency of subtelomeric, pure microduplications in a cohort of 624 patients with MR and/or multiple congenital anomalies using multiplex ligation dependent probe amplification (MLPA) and delineated the identified microduplications using array based comparative genomic hybridization (array CGH). In 11 patients, MLPA revealed a subtelomeric duplication without a concurrent deletion. Additional fluorescence in situ hybridization studies and parental analyses showed that three had occurred de novo: one duplication 5q34qter (12.7 Mb), one duplication 9q34.13qter (7.2 Mb) and one duplication 9p24.2pter (4.1 Mb). Five microduplications (9p, 11q, 12q, 15q and 16p) appeared to be inherited from an unaffected parent, while in three cases (9p, 12p and 17p) the parents were not available for testing. Based on our findings and data from the literature, the three de novo duplications were the only ones likely to be disease-causing, leading to a frequency of pathogenic subtelomeric, pure microduplications of 0.5%. Our study shows that subtelomeric microduplications are an infrequent cause of MR and that additional clinical and family studies are required to assess their clinical significance.

T-cell subpopulations in blood and cerebrospinal fluid of multiple sclerosis patients: effect of cyclophosphamide.

Monoclonal antibodies to various lymphocyte surface antigens were used for characterization of cerebrospinal fluid (CSF) and peripheral blood (PB) cells of patients with chronic progressive multiple sclerosis (MS) and of patients with other neurological diseases (OND). The effect of cyclophosphamide on these T-lymphocyte subpopulations in both compartments was studied. In the CSF of all patients 90 +/- 9% of the cells were T lymphocytes. T-helper/inducer (Th) lymphocytes comprised 70 +/- 9% and T-suppressor/cytotoxic (Ts) lymphocytes 31 +/- 10%. No significant differences in the percentages of T-lymphocyte subpopulations in CSF were observed between MS patients and patients with OND. The results obtained with monoclonal antibodies to Ia antigens suggested the presence of activated T cells in CSF of MS as well as OND patients. The mononuclear cell population isolated from PB of all patients contained 64 +/- 13% T lymphocytes, 44 +/- 11% Th cells, and 21 +/- 7% Ts cells. No significant difference in the ratio Th/Ts cells was observed between CSF and PB. The mononuclear cells isolated from the PB of untreated chronic progressive MS patients contained lower percentages of Ts cells (17 +/- 5%) and increased ratios of Th/Ts cells (3.1 +/- 1.6) compared to neurological controls (23 +/- 8% and 1.9 +/- 0.7) and healthy persons (23 +/- 6% and 1.9 +/- 0.5). In both PB and CSF, compared to untreated patients, cyclophosphamide-treated MS patients showed lower percentages of Th lymphocytes, whereas Ts-cell percentages were higher, leading to a normal ratio of Th/Ts cells in both compartments. The percentage of total T lymphocytes in PB was reduced by this treatment.

Lymphocyte subpopulations in multiple sclerosis: spontaneous and mitogen-induced activity.

Lymphocytes of chronic progressive multiple sclerosis (MS) patients and healthy persons were isolated by nylon-wool column filtration followed by density centrifugation. Incubating part of these lymphocytes with 2- aminoethyliso thiouronium bromide hydrobromide-treated sheep erythrocytes resulted in two other subfractions, the rosette-forming (E+) lymphocytes and the nonrosette -forming (E-) lymphocytes. Increased spontaneous activity was observed with the nonfractionated lymphocyte populations and with the E+- and E- -cell fractions of MS patients compared to the corresponding cell populations of controls following a culture period of one or several days. Phytohemagglutinin- and pokeweed mitogen-induced stimulation of these different lymphocyte fractions was the same in MS patients and controls. No influence of disease activity could be found on the immune parameters. Characterization of the different lymphocyte populations with monoclonal anti-human T-cell antibodies demonstrated a prevalence for helper T cells in forming rosettes.

The effect of cyclophosphamide on T lymphocytes and T lymphocyte subsets in patients with chronic progressive multiple sclerosis.

The lymphocytes in peripheral blood and cerebrospinal fluid of patients with chronic progressive multiple sclerosis (MS) were characterized with monoclonal antibodies to surface antigens of T cells, helper/inducer T cells and suppressor/cytotoxic T cells. The influence of cyclophosphamide treatment on these immune parameters was investigated. Compared to healthy persons, the mononuclear cell fraction of the peripheral blood of patients with chronic progressive MS consisted of normal %s of T cells and helper/inducer T cells, but decreased %s of suppressor/cytotoxic T lymphocytes. Intensive as well as chronic treatment of MS patients with cyclophosphamide resulted in a decline in the %s of T cells and helper/inducer T cells, whereas the %s of suppressor/cytotoxic T cells returned to normal. In cerebrospinal fluid, cyclophosphamide also induced a relative decrease in the % of helper/inducer T cells and an increase in the % of suppressor/cytotoxic T cells compared to untreated MS patients. Intensive as well as chronic therapy with cyclophosphamide both led to a significant decrease in the absolute number of T cells and T cell subsets in the blood of the patients.

Long-lasting effects of cyclophosphamide on lymphocytes in peripheral blood and spinal fluid.

Moderate doses of cyclophosphamide can cause effects on lymphocytes that may last for some time after discontinuation of the treatment. Since cyclophosphamide is also often used at high doses, we studied the short- and long-term effects of such a high dose (8 grams in 20 days) in 50 patients with chronic progressive multiple sclerosis with the use of monoclonal antibodies. The treatment caused a depletion of lymphocytes, especially CD4+ cells resulting in a significant decrease of the CD4/CD8 ratio. These changes can still be found up to 13.5 years after treatment. Although there was some recovery in the first few years after treatment this was only partial. Therefore, some of the effects of high dose cyclophosphamide on cellular immunity may be permanent. These changes should be taken into account when studying immune parameters or considering new treatments in these patients.

Cell-mediated immunity in multiple sclerosis as determined by sensitivity of different lymphocyte populations to various brain tissue antigens.

Peripheral blood lymphocytes from patients with multiple sclerosis (MS) or other neurological diseases and from healthy individuals were separated by density gradient sedimentation into several subfractions. Individual cell populations were cultured in the presence of several human brain tissue antigens. In comparison to controls, mononuclear cells with a density of less than 1.077 gm/cm3 from MS patients displayed a significantly increased sensitivity after incubation with purified human myelin basic protein (MBP) but not with other brain tissue antigens. In particular, the lymphocytes of patients suffering from MS for more than four years reacted positively with MBP, suggesting that the reaction dependent. No difference between MS patients and controls in sensitivity to any brain tissue antigen could be detected with cells of lower density (i.e., 1.073 to 1.069 gm/cm3 or less than 1.069 gm/cm3). Comparable lymphocyte activity was found to antigens isolated from both MS and control brain tissue. These results suggest that patients with chromic progressive MS have a secondary immune activity to MBP.

Spontaneous and mitogen-induced activity of lymphocytes of different density in multiple sclerosis.

Some immunological parameters of patients with multiple sclerosis (MS), of patients with other neurological diseases and of healthy volunteers were compared. No significant differences between these groups of persons were found in the number of leukocytes, granulocytes or lymphocytes per milliliter of peripheral blood. A density distribution profile of the peripheral blood mononuclear cells revealed a relatively increased number of low density cells (less than or greater than 1.069 g/cm3) and a relatively decreased number of cells with higher density (1.069-1.073 g/cm3) in MS patients as compared to healthy controls. The spontaneous activity and the pokeweed mitogen-induced activity of the different cell subfractions, separated according to density, appeared to be normal in MS patients. The results suggest a continuous stimulation of the immune system of MS patients resulting in a shift of cells towards lower density. This change was not related to disease duration or severity.