Extensive, 3.8 Mb-Sized Deletion of 22q12 in a Patient with Bilateral Schwannoma, Intellectual Disability, Sensorineural Hearing Loss, and Epilepsy.

Introduction: In contrast with the well-known and described deletion of the 22q11 chromosome region responsible for DiGeorge syndrome, 22q12 deletions are much rarer. Only a few dozen cases have been reported so far. This region contains genes responsible for cell cycle control, chromatin modification, transmembrane signaling, cell adhesion, and neural development, as well as several cancer predisposition genes. Case Presentation: We present a patient with cleft palate, sensorineural hearing loss, vestibular dysfunction, epilepsy, mild to moderate intellectual disability, divergent strabism, pes equinovarus, platyspondylia, and bilateral schwannoma. Using Microarray-based Comparative Genomic Hybridization (aCGH), we identified the de novo 3.8 Mb interstitial deletion at 22q12.1→22q12.3. We confirmed deletion of the critical NF2 region by MLPA analysis. Discussion: Large 22q12 deletion in the proband encases the critical NF2 region, responsible for development of bilateral schwannoma. We compared the phenotype of the patient with previously reported cases. Interestingly, our patient developed cleft palate even without deletion of the MN1 gene, deemed responsible in previous studies. We also strongly suspect the DEPDC5 gene deletion to be responsible for seizures, consistent with previously reported cases.

Case Report: Contiguous Xq22.3 Deletion Associated with ATS-ID Syndrome: From Genotype to Further Delineation of the Phenotype.

Alport syndrome with intellectual disability (ATS-ID, AMME complex; OMIM #300194) is an X-linked contiguous gene deletion syndrome associated with an Xq22.3 locus mainly characterized by hematuria, renal failure, hearing loss/deafness, neurodevelopmental disorder (NDD), midface retrusion, and elliptocytosis. It is thought that ATS-ID is caused by the loss of function of COL4A5 (ATS) and FACL4 (ACSL4) genes through the interstitial (micro)deletion of chromosomal band Xq22.3. We report detailed phenotypic description and results from genome-wide screening of a Czech family with diagnosis ATS-ID (proband, maternal uncle, and two female carriers). Female carriers showed mild clinical features of microscopic hematuria only, while affected males displayed several novel clinical features associated with ATS-ID. Utilization of whole-exome sequencing discovered the presence of approximately 3 Mb of deletion in the Xq23 area, which affected 19 genes from TSC22D3 to CHRDL1. We compared the clinical phenotype with previously reported three ATS-ID families worldwide and correlated their clinical manifestations with the incidence of genes in both telomeric and centromeric regions of the deleted chromosomal area. In addition to previously described phenotypes associated with aberrations in AMMECR1 and FACL4, we identified two genes, members of tripartite motif family MID2 and subunit of the proteasome PA700/19S complex (PSMD10), respectively, as prime candidate genes responsible for additional clinical features observed in our patients with ATS-ID. Overall, our findings further improve the knowledge about the clinical impact of Xq23 deletions and bring novel information about phenotype/genotype association of this chromosomal aberration.

Diagnosis of Bloom Syndrome in a Patient with Short Stature, Recurrence of Malignant Lymphoma, and Consanguineous Origin.

Bloom syndrome is an autosomal recessive disorder characterized by prenatal and postnatal growth deficiency, photosensitive skin changes, immune deficiency, insulin resistance, and a greatly increased risk of early-onset cancer and development of multiple malignancies. Loss-of-function variants of the BLM gene, which codes for a RecQ helicase, cause Bloom syndrome. We report a consanguineous family, with 2 siblings showing clinical signs of suspected chromosome breakage disorder. One of them developed recurrent malignant lymphoma during lifetime. We performed next-generation sequencing analysis, focusing on cancer predisposition syndromes. We identified a homozygous pathogenic nonsense variant c.1642C>T (p.Gln548*) in the BLM gene in the proband, associated with Bloom syndrome. Sanger sequencing validated the presence of a homozygous pathogenic variant in the proband and also in the brother with short stature. In this article, we will focus on the clinical presentation of the syndrome in this particular family as well as the characteristics of malignancies found in the proband.

Expanding the phenotype spectrum associated with pathogenic variants in the COL2A1 and COL11A1 genes.

We report the clinical findings of 26 individuals from 16 unrelated families carrying variants in the COL2A1 or COL11A1 genes. Using Sanger and next-generation sequencing, 11 different COL2A1 variants (seven novel), were identified in 13 families (19 affected individuals), all diagnosed with Stickler syndrome (STL) type 1. In nine families, the COL2A1 disease-causing variant arose de novo. Phenotypically, we observed myopia (95%) and retinal detachment (47%), joint hyperflexibility (92%), midface retrusion (84%), cleft palate (53%), and various degrees of hearing impairment (50%). One patient had a splenic artery aneurysm. One affected individual carrying pathogenic variant in COL2A1 showed no ocular signs including no evidence of membranous vitreous anomaly. In three families (seven affected individuals), three novel COL11A1 variants were found. The propositus with a de novo variant showed an ultrarare Marshall/STL overlap. In the second family, the only common clinical sign was postlingual progressive sensorineural hearing impairment (DFNA37). Affected individuals from the third family had typical STL2 signs. The spectrum of disease phenotypes associated with COL2A1 or COL11A1 variants continues to expand and includes typical STL and various bone dysplasias, but also nonsyndromic hearing impairment, isolated myopia with or without retinal detachment, and STL phenotype without clinically detectable ocular pathology.

DICER1 Syndrome.

DICER1 syndrome is an inherited disorder that increases the risk of different types of malignant and benign tumors. The syndrome is caused by mutations in the DICER1 gene, which is located on the long arm of chromosome 14, region q32.13. Patients with DICER1 syndrome commonly develop pleuropulmonary blastoma (PPB), multinodular goiter, ovarian Sertoli-Leydig cell tumors, and/or other types of tumors. In approximately 35% of families with children manifesting PPB, further (and rather rare) malignancies may be observed, including cystic nephroma, nodular dysplasia of the thyroid gland, medulloepithelioma of the iris, embryonal rhabdomyosarcoma botryoid type, nasal epithelial hamartoma, pituitary blastoma, and/or pineoblastoma. Large studies report a high variability of tumors associated with DICER1. DICER1 syndrome, which is associated with an inherited predisposition to tumors, is inherited in an autosomal dominant pattern. Symptoms of DICER1 syndrome may vary, even within families. Preventive screening of carriers with causative mutations is complicated. Follow-up is undertaken as recommended by the 2016 International PPB Register. This work was supported by grant of Ministry of Health of the Czech Republic AZV 16-3329A. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 4. 6. 2019 Accepted: 6. 6. 2019.

Mutational screening of inverted formin 2 in adult-onset focal segmental glomerulosclerosis or minimal change patients from the Czech Republic.

BACKGROUND: Mutations in INF2 are frequently responsible for focal segmental glomerulosclerosis (FSGS), which is a common cause of end stage renal disease (ESRD); additionally, they are also connected with Charcot-Marie-Tooth neuropathy. INF2 encodes for inverted formin 2. This protein participates in regulation of the dynamics of the actin cytoskeleton, involving not only the polymerisation, but also the depolymerisation of filaments. The present study is the first mutational analysis of INF2 done in the Czech Republic. METHODS: Mutational analysis of INF2 was performed on 109 patients (mean age at onset 41.44 ± 18.91 years) with FSGS or minimal change disease (MCD); and also in 6 patients without renal biopsy who had already developed chronic kidney disease (CKD)/ESRD at the time of diagnosis. We used high resolution melting method (HRM), with subsequent Sanger sequencing, in suspect samples from HRM analysis. The HRM method is an effective method for the screening of large cohorts of patients. RESULTS: Two pathogenic mutations (p.Arg214His and p.Arg218Gln) were detected in INF2. The first (p.Arg214His) was identified in the FSGS patient with a positive family history. The second mutation (p.Arg218Gln) was found in two brothers with ESRD of unknown etiology. The most frequent sequence change was the substitution p.P35P, the incidence of which corresponded with the frequencies available in the ExAC Browser and gnomAD Browser databases. This analysis also detected different exonic and intronic changes that probably did not influence the phenotype of the included patients. CONCLUSIONS: The INF2 mutational screening is useful in familial FSGS cases as well as in patients with an unknown cause for their ESRD, but with a positive family history. INF2 seems to be not only the cause of FSGS, but also of ESRD of unknown etiology. Our study has confirmed that the HRM analysis is a very useful method for the identification of single nucleotide substitutions.

Balanced chromosomal translocations in men: relationships among semen parameters, chromatin integrity, sperm meiotic segregation and aneuploidy.

PURPOSE: To analyse relationships between semen parameters, sperm chromatin integrity and frequencies of chromosomally unbalanced, disomic and diploid sperm in 13 Robertsonian and 37 reciprocal translocation carriers and to compare the results with data from 10 control donors. METHODS: Conventional semen analysis, Sperm Chromatin Structure Assay and FISH with probes for chromosomes involved in the individual translocations and for chromosomes X, Y, 7, 8, 13, 18 and 21. RESULTS: Normal semen parameters were found in 30.8 % of Robertsonian and 59.5 % of reciprocal translocation carriers. The rates of unbalanced sperm were 12.0 % in Robertsonian and 55.1 % in reciprocal translocation carriers with no difference between normospermic patients and those showing altered semen parameters. Significantly increased frequencies of spermatozoa showing defects in chromatin integrity and condensation, aneuploidy for chromosomes not involved in a translocation and diploidy were detected in translocation carriers with abnormal semen parameters. Normospermic reciprocal translocation carriers showed an increase in chromosome 13 disomy compared to the control group. There was no relationship between gametic and somatic aneuploidy in 12 translocation carriers studied by FISH on sperm and lymphocytes. The frequency of motile sperm was negatively correlated with the frequency of sperm showing disomy, diploidy and defective chromatin condensation. CONCLUSIONS: Abnormal semen parameters can serve as indicators of an additional risk of forming spermatozoa with defective chromatin and aneuploidy in translocation carriers.

der(4)t(Y;4): Three-generation transmission and sperm meiotic segregation analysis.

We present a family where five members (three males and two females) are carriers of der(4)t(Y;4)(q11.23;p16.3). The adult carriers are phenotypicaly normal and fertile; the boy shows macrocephaly, psychomotor retardation, and atypical autism. The FISH on cultured lymphocytes confirmed that the redundant Yq heterochromatin was attached to the 4p-subtelomeric region maintained on the der(4). Sperm FISH analysis performed in a normospermic der(4) carrier showed a significant distortion of the expected 1:1 ratio of the X- and Y-bearing spermatozoa in favor of the X chromosome and significant lack of Y,der(4)spermatozoa. The overall lack of Y spermatozoa was not balanced even by a relative excess of Y,4 sperm. The analysis of X, Y, 7, 8, 18, and 21 sperm disomy and diploidy did not indicate any interchromosomal effect. The chromosome 4 disomy was significantly increased but still very low to be of considerable reproductive significance. The neurodevelomental phenotype of the boy was probably caused by a gene mutation. The coincidental occurrence of such chromosomal aberration and boy's phenotype might lead to misinterpretation of the causal relationship between these findings. It is necessary to consider the results of chromosomal analysis and clinical records of relatives for provide genetic counseling in such families.

Malignant intracranial germinoma in Smith-Lemli-Opitz syndrome: cholesterol homeostasis possibly connecting morphogenesis and cancer development.

Smith-Lemli-Opitz syndrome is a rare hereditary autosomal recessive disease characterized by deficiency of 7-dehydrocholesterol reductase. Clinical picture encompasses prenatal and postnatal growth abnormalities and multisystemic structural malformations. To date, predisposition for tumor development is not considered a feature associated with this syndrome. Here, we describe a 16-year-old boy with Smith-Lemli-Opitz syndrome who developed cerebral germinoma. To our knowledge, this is the first report of association of this syndrome with malignant intracranial germ-cell tumor.

Sperm fluorescence in situ hybridization study of meiotic segregation and an interchromosomal effect in carriers of t(11;18).

BACKGROUND: Alanced translocations are associated with infertility, spontaneous abortions and birth defects. METHODS: We report the analysis, by multicolour fluorescence in situ hybridization (FISH), of meiotic segregation and aneuploidy of chromosomes X, Y, 7, 8 and 21 in sperm from three men who are carriers of two different translocations involving chromosomes 11 and 18. A control group comprised ten young, healthy normospermic men. RESULTS: The higher prevalence of alternate segregation followed by adjacent 1, adjacent 2 and 3:1, and other segregants was observed in all three patients. Two carriers of the same translocation differed only in the frequency of adjacent 2 segregation (P < 0.01). The carrier of the other translocation showed significantly higher frequency of alternate (P < 0.01) and less adjacent 1 and 3:1 segregation products (P < 0.01). An increased frequency of XY (P < 0.01), YY (P < 0.05) and diploid (P < 0.01) sperm was also detected in the group of translocation carriers compared with the control group. This difference was caused by elevated frequencies of disomy and diploidy in two of our carriers. CONCLUSIONS: The incidence of chromosomally unbalanced or aneuploid gametes varies in the individual translocation carriers even if the same chromosomes are included in the translocation. FISH analysis provides information useful for genetic counseling and assisted reproduction.

TSPY gene copy number as a potential new risk factor for male infertility.

The human TSPY (testis-specific protein, Y-linked) gene family (30-60 copies) is situated in the MSY (male-specific) region of the Y chromosome. Testis-specific expression indicates that the gene plays a role in spermatogenesis. Refined quantitative fluorescence PCR (polymerase chain reaction) was applied to evaluate the relative number of TSPY copies compared with AMELY/X (amelogenin gene, Y-linked) genes in 84 stratified infertile men and in 40 controls. A significantly higher number of TSPY copies was found in infertile men compared with the controls (P = 0.002). The diagnostic discrimination potential of the relative number of TSPY copies was evaluated by receiver operating characteristic curve analysis. TSPY/AMELY was unambiguously found to be powerful in the diagnostic separation of both the control samples and the infertile men, reaching a good level of specificity (0.642) and sensitivity (0.732) at a cut-off point of 0.46. The findings were supported by independently repeated studies of randomly selected positive samples and controls. Evaluation of the TSPY copy number offers a completely new diagnostic approach in relation to the genetic cause of male infertility. The possible effect of the copy number of TSPY genes on spermatogenesis may explain indiscrete pathological alterations of spermatid quality and quantity.