Prenatal detection of copy number variants in fetuses with detected congenital devolpmental disordes, from 2015 to 2020 by Multiplex Ligation-Dependent Probe Amplification and microarray analysis.

OBJECTIVE: Analysis of prenatal samples from 2015 to 2020. Comparison detection rates of clinically relevant variants by cytogenetic karyotype analysis and cytogenomic MLPA (Multiplex Ligation-Depent Probe Amplification) and microarray methods (CMA - chromosomal microarray). MATERIAL AND METHOD: 1,029 prenatal samples were analyzed by cytogenetic karyotyping (N = 1,029), cytogenomic methods - MLPA (N = 144) and CMA (N = 111). All unbalanced changes were confirmed by MLPA or CMA. RESULTS: From the analyzed set of fetuses, after subtraction of aneuploidies - 107 (10.40%, N = 1,029), 22 structural aberrations (2.39%, N = 922) - nine unbalanced changes (0.98%), 10 balanced changes (1.08%), one case of unclear mosaicism (0.09%), one case of presence of a marker chromosome (0.09%) and one case of sex discordance (0.09%) - were detected by karyotype analysis. A total of eight (7.21%, N = 111) pathological variants were detected by CMA in 255 samples with physiological karyotype indicated for cytogenomic examination. Five (3.47%, N = 144) of eight pathogenic variants were detected by MLPA method. The total capture of pathogenic variants by MLPA and CMA methods was 14 (5.14%) and 17 (6.25%) (N = 272), including confirmatory pathological karyotype testing. Detection of pathological variants in the isolated disorders group was lower than in the multiple disorders group (5.08 vs. 21.42%). CONCLUSION: A higher success rate for the detection of pathological copy number variation variants by the microarray method than by the MLPA method was confirmed.

Single giant mediastinal rhabdomyoma as a sole manifestation of TSC in foetus.

BACKGROUND: Presence of multiple cardiac rhabdomyomas is one of the major features of Tuberous sclerosis (TSC), but isolated progressing single giant rhabdomyoma is very rare and not typical of TSC. CASE REPORT: This report presents family without obvious history of TSC with occurrence of giant mediastinal rhabdomyoma affecting the haemodynamics in male foetus, without other TSC symptoms. Girl from the next gravidity had prenatally detected multiple rhabdomyomas and small subcortical tuber of brain detected after birth. DNA analysis found novel c.4861A>T TSC2 variant and large deletion in TSC2 in tumour tissue from male foetus. The novel TSC2 variant was also present in the girl and her healthy father, in silico analysis suggested its functional effect on TSC2. Brain MRI of the father detected mild TSC specific abnormality. CONCLUSION: We suggest the novel TSC2 mutation is a cause of mild TSC in this family and has reduced expression. The clinical and molecular findings in this family also emphasize that TSC diagnosis should be also evaluated in case of single giant foetal cardiac rhabdomyoma.

Clinical Potential of Effective Noninvasive Exclusion of KEL1-Positive Fetuses in KEL1-Negative Pregnant Women.

BACKGROUND: The clinical importance of assessing the fetal KEL genotype is to exclude 'K'-positive fetuses (genotype KEL1/KEL2) in 'K'-alloimmunized pregnant women (genotype KEL2/KEL2). Noninvasive assessment of the fetal KEL genotype is not yet available in the Czech Republic. OBJECTIVE: The aim of this study was to assess the fetal KEL1/KEL2 genotype from cell-free fetal DNA in the plasma of KEL2/KEL2 pregnant women. METHODS: The fetal genotype was assessed by minisequencing (a dilution series including control samples). A total of 138 pregnant women (between the 8th and 23rd gestational week) were tested by minisequencing. The fetal genotype was further verified by analysis of a buccal swab from the newborn. RESULTS: Minisequencing proved to be a reliable method. In 2.2% (3/138) of the examined women, plasma sample testing failed; 94.8% (128/135) had the KEL2/KEL2 genotype, and a total of 3.1% of fetuses (4/128) had the KEL1/KEL2 genotype. Sensitivity and specificity reached 100% (p < 0.0001). CONCLUSION: Minisequencing is a reliable method for the assessment of the fetal KEL1 allele from the plasma of KEL2/KEL2 pregnant women.

Giant angiofibromas in tuberous sclerosis complex: a possible role for localized lymphedema in their pathogenesis.

BACKGROUND: Giant angiofibromas in patients with tuberous sclerosis complex (TSC) are rare. OBJECTIVE: We sought to report two patients who had TSC with unusually large and disfiguring facial angiofibromas and to identify underlying histopathologic changes that may possibly explain the clinical features. METHODS: We performed a clinicopathologic, immunohistochemical, and molecular biologic study using 42 lesional specimens and peripheral blood from one of the two patients. The immunohistochemical investigations were mainly focused on the vascular moiety of the lesions. TSC1 and TSC2 alterations were studied using multiplex ligation-dependent probe amplification for large deletion/duplication mutations, whereas screening for small mutations was performed using polymerase chain reaction amplification of individual coding exons and exon-intron junctions of both genes followed by an analysis on denaturation gradient gel electrophoresis. RESULTS: Histopathologic examination revealed, in addition to findings typical of angiofibroma, several unusual features including multinucleated giant cells containing multiple intracytoplasmic vacuoles, Touton-like cells, emperipolesis, pagetoid dyskeratosis, vacuolar alteration at the dermoepidermal junction, Civatte bodies, and melanophages in the subjacent dermis. Numerous dilated lymphatic vessels were detected indicating localized lymphostasis, probably caused by secondary lymphedema. The lymphatic nature of the vessels was confirmed by immunohistochemical study. Genetic testing for TSC1 and TSC2 gene mutations revealed a substitution on position c.2251C>T resulting in a nonsense mutation R751X in fragment 20.2. LIMITATIONS: Histopathologic specimens and peripheral blood were available from only one patient. CONCLUSION: Localized lymphedema may contribute to the formation of large disfiguring angiofibromas in patients with TSC.