Evolution of P-wave indices during long-term follow-up as markers of atrial substrate progression in arrhythmogenic right ventricular cardiomyopathy.

AIMS: Patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) have increased prevalence of atrial arrhythmias indicating atrial involvement in the disease. We aimed to assess the long-term evolution of P-wave indices as electrocardiographic (ECG) markers of atrial substrate during ARVC progression. METHODS AND RESULTS: We included 100 patients with a definite ARVC diagnosis according to 2010 Task Force criteria [34% females, median age 41 (inter-quartile range 30-55) years]. All available sinus rhythm ECGs (n = 1504) were extracted from the regional electronic ECG databases and automatically processed using Glasgow algorithm. P-wave duration, P-wave area, P-wave frontal axis, and prevalence of abnormal P terminal force in lead V1 (aPTF-V1) were assessed and compared at ARVC diagnosis, 10 years before and up to 15 years after diagnosis.Prior to ARVC diagnosis, none of the P-wave indices differed significantly from the data at ARVC diagnosis. After ascertainment of ARVC diagnosis, P-wave area in lead V1 decreased from -1 to -30 µV ms at 5 years (P = 0.002). P-wave area in lead V2 decreased from 82 µV ms at ARVC diagnosis to 42 µV ms 10 years after ARVC diagnosis (P = 0.006). The prevalence of aPTF-V1 increased from 5% at ARVC diagnosis to 18% by the 15th year of follow-up (P = 0.004). P-wave duration and frontal axis did not change during disease progression. CONCLUSION: Initial ARVC progression was associated with P-wave flattening in right precordial leads and in later disease stages an increased prevalence of aPTF-V1 was seen.

Enhancing rare variant interpretation in inherited arrhythmias through quantitative analysis of consortium disease cohorts and population controls.

PURPOSE: Stringent variant interpretation guidelines can lead to high rates of variants of uncertain significance (VUS) for genetically heterogeneous disease like long QT syndrome (LQTS) and Brugada syndrome (BrS). Quantitative and disease-specific customization of American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines can address this false negative rate. METHODS: We compared rare variant frequencies from 1847 LQTS (KCNQ1/KCNH2/SCN5A) and 3335 BrS (SCN5A) cases from the International LQTS/BrS Genetics Consortia to population-specific gnomAD data and developed disease-specific criteria for ACMG/AMP evidence classes-rarity (PM2/BS1 rules) and case enrichment of individual (PS4) and domain-specific (PM1) variants. RESULTS: Rare SCN5A variant prevalence differed between European (20.8%) and Japanese (8.9%) BrS patients (p = 5.7 × 10-18) and diagnosis with spontaneous (28.7%) versus induced (15.8%) Brugada type 1 electrocardiogram (ECG) (p = 1.3 × 10-13). Ion channel transmembrane regions and specific N-terminus (KCNH2) and C-terminus (KCNQ1/KCNH2) domains were characterized by high enrichment of case variants and >95% probability of pathogenicity. Applying the customized rules, 17.4% of European BrS and 74.8% of European LQTS cases had (likely) pathogenic variants, compared with estimated diagnostic yields (case excess over gnomAD) of 19.2%/82.1%, reducing VUS prevalence to close to background rare variant frequency. CONCLUSION: Large case-control data sets enable quantitative implementation of ACMG/AMP guidelines and increased sensitivity for inherited arrhythmia genetic testing.

Danon disease presenting with early onset of hypertrophic cardiomyopathy and peripheral pigmentary retinal dystrophy in a female with a de novo novel mosaic mutation in the LAMP2 gene.

Purpose: To describe the phenotype and genotype in a young woman with Danon disease. Methods: The patient underwent an ophthalmic examination including best corrected visual acuity (BCVA), fundus photography and fundus autofluorescence (FAF), full-field electroretinography (full-field ERG), multifocal ERG, optical coherence tomography (OCT) and SAP-Humphrey 30-2 at the ages of 20 and 25. Electrooculography, fluorescein angiography (FA), indocyanine angiography and OCT angiography were performed only once. Genetic testing using a Next-Generation Sequencing panel and immunohistochemical analysis of LAMP2 protein expression were performed in the patient's explanted heart, and the patient's cardiologic and ophthalmologic records were retrospectively reviewed. Results: A de novo, novel, mosaic mutation, c.135dupA; p.(Trp46Metfs*10) was identified in exon 2 of the LAMP2 gene. Immunohistochemical investigation of the myocardium in the explanted heart revealed pronounced deficiency of LAMP2 protein in cardiomyocytes. The color photographs, FAF images and FA revealed more extensive peripheral pigmentary retinal dystrophy (PPRD) at the 5-year follow-up examination. No changes were observed in BCVA, OCT, SAP-Humphrey 30-2 or multifocal ERG findings at follow-up. Full-field ERG showed an asymmetric interocular reduction in ERG response at follow-up: the b-wave amplitude of the rod response had decreased by 29% in the right eye, but by only 6 % in the left eye. The a-wave amplitude of single-flash response had decreased by 9 % in the left eye, while it had increased by 3% in the right eye. Conclusions: Although PPRD progressed slowly, it was an important clue in the diagnosis of the life-threatening condition of Danon disease.

Rare novel variants in the ZIC3 gene cause X-linked heterotaxy.

Variants in the ZIC3 gene are rare, but have demonstrated their profound clinical significance in X-linked heterotaxy, affecting in particular male patients with abnormal arrangement of thoracic and visceral organs. Several reports have shown relevance of ZIC3 gene variants in both familial and sporadic cases and with a predominance of mutations detected in zinc-finger domains. No studies so far have assessed the functional consequences of ZIC3 variants in an in vivo model organism. A study population of 348 patients collected over more than 10 years with a large variety of congenital heart disease including heterotaxy was screened for variants in the ZIC3 gene. Functional effects of three variants were assessed both in vitro and in vivo in the zebrafish. We identified six novel pathogenic variants (1,7%), all in either male patients with heterotaxy (n=5) or a female patient with multiple male deaths due to heterotaxy in the family (n=1). All variants were located within the zinc-finger domains or leading to a truncation before these domains. Truncating variants showed abnormal trafficking of mutated ZIC3 proteins, whereas the missense variant showed normal trafficking. Overexpression of wild-type and mutated ZIC protein in zebrafish showed full non-functionality of the two frame-shift variants and partial activity of the missense variant compared with wild-type, further underscoring the pathogenic character of these variants. Concluding, we greatly expanded the number of causative variants in ZIC3 and delineated the functional effects of three variants using in vitro and in vivo model systems.

Constitutional and somatic deletions of the Williams-Beuren syndrome critical region in non-Hodgkin lymphoma.

Here, we report and investigate the genomic alterations of two novel cases of Non-Hodgkin Lymphoma (NHL) in children with Williams-Beuren syndrome (WBS), a multisystem disorder caused by 7q11.23 hemizygous deletion. Additionally, we report the case of a child with NHL and a somatic 7q11.23 deletion. Although the WBS critical region has not yet been identified as a susceptibility locus in NHL, it harbors a number of genes involved in DNA repair. The high proportion of pediatric NHL reported in WBS is intriguing. Therefore, the role of haploinsufficiency of genes located at 7q11.23 in lymphomagenesis deserves to be investigated.

Clinical and genetic features of pediatric acute lymphoblastic leukemia in Down syndrome in the Nordic countries.

BACKGROUND: Children with Down syndrome (DS) have an increased risk for acute lymphoblastic leukemia (ALL). Although previous studies have shown that DS-ALL differs clinically and genetically from non-DS-ALL, much remains to be elucidated as regards genetic and prognostic factors in DS-ALL. METHODS: To address clinical and genetic differences between DS-ALL and non-DS-ALL and to identify prognostic factors in DS-ALL, we ascertained and reviewed all 128 pediatric DS-ALL diagnosed in the Nordic countries between 1981 and 2010. Their clinical and genetic features were compared with those of the 4,647 B-cell precursor (BCP) ALL cases diagnosed during the same time period. RESULTS: All 128 DS-ALL were BCP ALL, comprising 2.7% of all such cases. The 5-year event-free survival (EFS) and overall survival (OS) were significantly (P = 0.026 and P = 0.003, respectively) worse for DS-ALL patients with white blood cell counts ≥50 × 109/l. The age distributions varied between the DS and non-DS cases, with age peaks at 2 and 3 years, respectively; none of the DS patients had infant ALL (P = 0.029). The platelet counts were lower in the DS-ALL group (P = 0.005). Abnormal karyotypes were more common in non-DS-ALL (P < 0.0001), and there was a significant difference in the modal number distribution, with only 2% high hyperdiploid DS-ALL cases (P < 0.0001). The 5-year EFS and 5-year OS were significantly worse for DS-ALL (0.574 and 0.691, respectively) compared with non-DS-ALL (0.783 and 0.894, respectively) in the NOPHO ALL-1992/2000 protocols (P < 0.001). CONCLUSIONS: The present study adds further support for genetic and clinical differences between DS-ALL and non-DS-ALL.

Submicroscopic genomic imbalances in Burkitt lymphomas/leukemias: association with age and further evidence that 8q24/MYC translocations are not sufficient for leukemogenesis.

Chromosome banding analyses reveal secondary chromosome abnormalities in addition to the MYC translocations t(8;14)(q24;q32), t(8;22)(q24;q11), and t(2;8)(p11;q24) in 60%-80% of Burkitt lymphomas/leukemias (BL). The high incidence of such aberrations indicates that additional changes are important, perhaps necessary, for malignant transformation, i.e., the 8q24/MYC rearrangements may not be sufficient. To investigate this possibility, we performed single nucleotide polymorphism (SNP) array analysis on 20 cases of 8q24/MYC-positive BL. Nineteen (95%) harbored genomic imbalances; the only case without such aberrations displayed secondary changes by chromosome banding analysis. Thus, all BL cases had abnormalities in addition to the 8q24 translocation. The adult cases harbored more changes (median 3; range 1-21) than did the childhood cases (median 1.5; range 0-5) (P = 0.034). Several recurrent aberrations were detected by SNP array analysis, in particular losses of 6q14.1-q22.33, 9p21.3, and 13q14.2-q14.3, gains of 1q23.3-q31.3, chromosome 7, 13q31.3, and partial uniparental isodisomies for 6p12.2-pter, 9p23-pter, and 17p11.2-pter. The molecular genetic consequences of these changes include deletions of the CDKN2A and TP53 genes, and gains/losses of several genes, such as MIR17HG and E2F2K, involved in the MYC pathway. Thus, deregulation of the MYC pathway, both directly through the 8q24/MYC translocation and indirectly through secondary genomic imbalances, may be essential not only for the initiation but also for the progression of BL.

High frequency of BTG1 deletions in acute lymphoblastic leukemia in children with down syndrome.

Previous cytogenetic studies of myeloid and acute lymphoblastic leukemias in children with Down syndrome (ML-DS and DS-ALL) have revealed significant differences in abnormality patterns between such cases and acute leukemias in general. Also, certain molecular genetic aberrations characterize DS-related leukemias, such as GATA1 mutations in ML-DS and deregulation of the CRLF2 gene in DS-ALL. Whether microdeletions/microduplications also vary between DS and non-DS cases is presently unclear. To address this issue, we performed single nucleotide polymorphism array analyses of eight pediatric ML-DS and 17 B-cell precursor DS-ALL. In the ML-DS cases, a total of 29 imbalances (20 gains and nine losses) and two partial uniparental isodisomies (pUPDs) were detected. None of the 11 small (defined as <10 Mb) imbalances were recurrent, nor were the pUPDs, whereas of the 18 large aberrations, three were recurrent-dup(1q), +8 and +21. In contrast, several frequent changes were identified in the DS-ALL cases, which harbored 82 imbalances (30 gains and 52 losses) and four pUPDs. Of the 40 large changes, 28 were gains and 12 losses, with +X, dup(Xq), dup(1q), del(7p), dup(8q), del(9p), dup(9p), del(12p), dup(17q), and +21 being recurrent. Of the 40 microdeletions identified, several targeted specific genes, with the following being repeatedly deleted: BTG1 and CDKN2A/B (29% of cases), ETV6, IKZF1, PAX5 and SERP2 (18%), and BTLA, INPP4B, P2RY8, and RB1 (12%). Loss of the SERP2 and INPP4B genes, encoding the stress-associated endoplasmic reticulum protein family member 2 and the inositol polyphosphate 4-phosphatase-II, respectively, has previously never been implicated in leukemia. Although deletions of the other genes have been associated with ALL, the high frequency of BTG1 loss is a novel finding. Such deletions may characterize a clinical subgroup of DS-ALL, comprising mainly boys with a high median age. In conclusion, ML-DS and DS-ALL are genetically distinct, with mainly gains in ML-DS and deletions in DS-ALL. Furthermore, DS-ALL is characterized by several recurrent gene deletions, with BTG1 loss being particularly frequent.

Ultrasonographic findings in spontaneous miscarriage: relation to euploidy and aneuploidy.

OBJECTIVE: To evaluate a possible correlation between transvaginal ultrasound findings in miscarriages and cytogenetic analyses from chorionic villi obtained by dilatation and curettage. DESIGN: Prospective, population-based study. SETTING: University-based hospital. PATIENT(S): Five hundred seventy-six women with spontaneous miscarriage diagnosed between 6 and 12 completed pregnancy weeks. INTERVENTION(S): Transvaginal ultrasonography and dilatation and curettage. MAIN OUTCOME MEASURE(S): Cytogenetic analyses and ultrasound measurement of embryonic pole. RESULT(S): The mean gestational age was 9.5 weeks. Chromosomal analyses were successful in 259 cases, 159 with cytogenetic abnormalities and 100 euploidy. Empty gestational sacs were equally often found in euploidy and aneuploidy, whereas small embryonic or fetal poles were significantly more often associated with aneuploidy. CONCLUSION(S): A smaller than expected fetal size when a miscarriage is diagnosed during the first trimester is significantly associated with a chromosomal aberration.

B-cell precursor t(8;14)(q11;q32)-positive acute lymphoblastic leukemia in children is strongly associated with Down syndrome or with a concomitant Philadelphia chromosome.

We review the clinical and cytogenetic features of 44 acute lymphoblastic leukemias (ALLs) with t(8;14)(q11;q32), including three from our department and 41 ascertained in the literature, focusing on age and gender distribution, peripheral blood values, immunophenotypic data, survival and additional chromosomal changes. Most patients are children or young adults, with a median age of 10 yr for children and 28 for adults. There is a male preponderance, particularly in patients with Down syndrome (DS) or in children with concomitant t(9;22)(q34;q11). The median blood values are hemoglobin 72 g/L, platelets 17 x 10(9)/L and white blood cell count 9 x 10(9)/L, with hyperleukocytosis >50 x 10(9)/L having been reported in only approximately 10%. All reported cases have had a B-cell precursor immunophenotype, typically characterized by CD10+, CD19+, CD20+/-, CD22+, CD24+, CD34+, CD45dim/-, CD66c+/- and CD123+. At the time of reporting, 75% of the patients have been alive. The t(8;14) is the sole acquired change in 30%. The most common additional aberrations are t(9;22)(q34;q11), der(14)t(8;14), +21, +X and +14, the presence of which does not seem to confer a prognostic impact. A substantial proportion of the patients have DS (27%) or t(9;22) (16%). All patients with both t(8;14) and t(9;22) have been children without DS; the frequency of t(9;22) in that cohort is 30%. As t(9;22), or its molecular genetic correlate, may escape detection by conventional banding analysis we would strongly suggest that this aberration is actively looked for in pediatric ALL with t(8;14).

Chromosomal anomalies in first-trimester miscarriages.

BACKGROUND: It is well known that a large proportion of first-trimester spontaneous abortions is caused by chromosomal disorders. The present study represents a unique material and the success rate of the karyotyping was high. METHODS: Chromosomal analysis from chorionic villus sampling of 259 of 304 consecutive first-trimester miscarriages in the Uppsala County, Sweden is presented. RESULTS AND CONCLUSIONS: An abnormal karyotype was found in 61% of the cases. Autosomal trisomies were most frequently detected (in 37% of the karyotyped samples), followed by polyploidies (9%) and monosomy X (6%). Cases with an extra sex chromosome constituted approximately 5% of the karyotyped abortions, with a remarkable high frequency of 47,XXY (3.4%), that is approximately 40 times greater the prevalence of Klinefelter syndrome among live birth. Similar to autosomal chromosome abnormalities, present finding indicates that the majority of sex chromosome abnormalities do not survive to term. Autosomal trisomies and an extra X-chromosome in males (47,XXY) were associated with an advanced maternal age, whereas monosomy X as well as polyploidy changes seems to be inversely related to the age of the mother. The single most common aberration was trisomy 16, which was found in 14% of the chromosomally abnormal abortions.

Cytogenetic abnormalities in childhood acute myeloid leukaemia: a Nordic series comprising all children enrolled in the NOPHO-93-AML trial between 1993 and 2001.

Between 1993 and 2001, 318 children were diagnosed with acute myeloid leukaemia (AML) in the Nordic countries. The patient group comprised 237 children < 15 years of age with de novo AML, 42 children < 15 years with Down syndrome (DS) and de novo AML, 18 adolescents 15-18 years of age with de novo AML, and 21 children < 15 years with treatment-related AML (t-AML). The first group was all-inclusive, yielding an annual childhood de novo AML incidence of 0.7/100 000. Cytogenetic analyses were successful in 288 cases (91%), and clonal chromosomal abnormalities were detected in 211 (73%). The distribution of ploidy levels were pseudodiploidy (55%), hyperdiploidy (34%) and hypodiploidy (11%). The most common aberrations (> 2%) were + 8 (23%) (as a sole change in 6.2%), 11q23-translocations, including cryptic MLL rearrangements (22%) [t(9;11)(p21-22;q23) in 11%], t(8;21)(q22;q22) (9.0%), inv(16)(p13q22) (6.2%), -7/7q- (5.2%), and t(15;17)(q22;q12) (3.8%). Except for +8, these abnormalities were rare in group 2; only one DS patient had a t(8;21) and none had 11q23-translocations, t(15;17) or inv(16). In the t-AML group, three cases displayed 11q23-rearrangements, all t(9;11); and there were no t(8;21), t(15;17) or inv(16). Overall, the observed frequencies of t(8;21) and t(15;17) were lower, and frequencies of trisomy 8 and 11q23-translocations higher, than in previous studies. Furthermore, seven abnormalities that were previously reported as only single AML cases were also seen, meaning that der(4)t(4;11)(q26-27;q23), der(6)t(1;6)(q24-25;q27), der(7)t(7;11)(p22;q13), inv(8)(p23q11-12), t(11;17)(p15;q21), der(16)t(10;16)(q22;p13) and der(22)t(1;22)(q21;q13) are now classified as recurrent abnormalities in AML. In addition, 37 novel aberrations were observed, 11 of which were sole anomalies.

Trisomy 4q syndrome: presentation of a new case and review of the literature.

We describe the 11th case of a de novo partial trisomy of the long arm of chromosome 4, with the extra segment spanning from 4q27 to 4q35. The aberration resulted from an unbalanced translocation of material from 4q to the short arm of chromosome 7, as evident from fluorescent in situ hybridization. Microsatellite analysis revealed the extra material to originate from the father. The karyotype was interpreted as 46,XX,der(7)t(4;7)(q27;p22). The patient is a 13-year-old girl with severe mental retardation, growth retardation, hearing impairment as well as minor foot, thumb and facial anomalies. Although the extent of the aberration varies between the reported patients, there are nevertheless features in common, suggestive of a trisomy 4q syndrome. The clinical findings most frequently reported are: mental retardation, seizures, microcephaly, hearing impairment and growth retardation, as well as epicanthic folds, high/broad/depressed nasal bridge, malformed ears, tooth and thumb anomalies. Almost the entire long arm of chromosome 4, except band q11, has been involved in trisomies/duplications, but 4q27 and 4q31 seem to be preferentially engaged in the trisomy 4q syndrome.