An asymptomatic male individual carrying a 5.72 Mb de novo deletion in 8p23.2­p23.3: A case report.

Numerous rearrangements in the 8p23 chromosomal region have been reported; included in these rearrangements are isolated deletions in this area. Such deletions are associated with a wide range of phenotypic characteristics, including motor impairment, epilepsy, intellectual disability, cardiac defects and seizures. The present study describes the case of a 30-year-old asymptomatic man that carries a de novo deletion in 8p23.2-p23.3. Molecular karyotyping indicated that the detected deletion involves genes that are in the critical region which is hypothesized to be responsible for the phenotypic characteristics associated with such deletions. The normal phenotype of the patient supports the hypothesis that there is incomplete penetrance of 8p23.2-p23.3 deletions.

Prenatal Identification of a Missense Mutation of the L1CAM Gene Associated With Hydrocephalus Using Next-Generation Sequencing.

We present the case of a 35-year-old pregnant woman who visited our department for a routine ultrasonography screening scan for fetus anatomy during the 22nd week of gestation. Our report revealed a male fetus with marked hydrocephalus and severe intrauterine growth retardation. After extensive counseling, the couple decided to proceed with an invasive diagnosis via amniocentesis. The cytogenetic analysis showed findings related to clinical history and ultrasound findings related to the presence of a nucleotide change in c.578T>C with an amino acid change in p.Leu198Pro of the L1CAM gene. The result was reported as a hemizygote missense L1CAM gene variant of unknown significance. After extensive parental counseling, the couple decided on pregnancy termination. We report the present case of L1CAM mutation in p.Leu198Pro to add to the limited knowledge regarding the clinical presentation of mutations of the L1CAM gene with emphasis on prenatal diagnosis.

Prenatal diagnosis of 18p deletion and 8p trisomy syndrome: literature review and report of a novel case.

18p deletion syndrome constitutes one of the most frequent autosomal terminal deletion syndromes, affecting one in 50,000 live births. The syndrome has un-specific clinical features which vary significantly between patients and may overlap with other genetic conditions. Its prenatal description is extremely rare as the fetal phenotype is often not present during pregnancy. Trisomy 8p Syndrome is characterized by heterogenous phenotype, with the most frequent components to be cardiac malformation, developmental and intellectual delay. Its prenatal diagnosis is very rare due to the unspecific sonographic features of the affected fetuses. We present a very rare case of a fetus with multiple anomalies diagnosed during the second trimester whose genomic analysis revealed a 18p Deletion and 8p trisomy Syndrome. This is the first case where this combination of DNA mutations has been described prenatally and the second case in general. The presentation of this case, as well as the detailed review of all described cases, aim to expand the existing knowledge regarding this rare condition facilitating its diagnosis in the future.

The Effect of Resolution Level and Targeted Design in the Diagnostic Performance of Prenatal Chromosomal Microarray Analysis.

INTRODUCTION: This study was performed to assess the optimal resolution for prenatal testing by array comparative genomic hybridization (aCGH), aiming to balance between maximum diagnostic yield and minimal detection of variants of uncertain significance (VOUS). METHODS: This was a prospective study using data of 2,336 fetuses that underwent invasive prenatal diagnosis, and the samples were analyzed by aCGH. In total, six different aCGH platforms were studied; four different resolutions (0.18 Mb, 0.5 Mb, 1 Mb, and 2 Mb) and two platform designs (whole-genome [WG] and targeted). The results of these designs were compared based on their diagnostic yield and VOUS rate. The performance of the different designs was further analyzed according to indication for invasive testing. RESULTS: The diagnostic yield of copy number variants increased with increasing level of analysis. The detection rates of clinically significant chromosomal abnormalities were almost the same across our targeted array designs; 7.2% with 0.18 Mb backbone/0.05 Mb versus 7.1% with 0.5 Mb backbone/0.05 Mb (p >0.05). However, a significant difference in the rate of VOUS was observed; 9.4% with 0.18 Mb backbone/0.05 Mb versus 6% with 0.5 Mb backbone/0.05 Mb (p <0.001). After analyzing the results across different indications for testing, we found that the application of non-targeted platform designs and lower levels of resolution analysis (such as 1 Mb WG or 0.5 MbL/1 MbG WG) would offer similar diagnostic yield in most cases with major congenital anomalies, with lower VOUS rates. However, the sample size for many indication groups was too small to extract robust associations. CONCLUSION: It appears that the targeted array platform with 0.5 Mb backbone resolution and 0.05 Mb on targeted gene-rich regions is optimal for routine chromosomal microarray analysis use in prenatal diagnosis. It may be beneficial to individualize the minimum resolution in specific referral indications as the indications for invasive prenatal testing may be quite heterogeneous.

Prenatal Identification of a Novel Mutation in the MCPH1 Gene Associated with Autosomal Recessive Primary Microcephaly (MCPH) Using Next Generation Sequencing (NGS): A Case Report and Review of the Literature.

BACKGROUND: MCPH1 is known as the microcephalin gene (OMIM: *607117), of which the encoding protein is a basic regulator of chromosome condensation (BCRT-BRCA1 C-terminus). The microcephalin protein is made up of three BCRT domains and conserved tandem repeats of interacting phospho-peptides. There is a strong connection between mutations of the MCPH1 gene and reduced brain growth. Specifically, individuals with such mutations have underdeveloped brains, varying levels of mental retardation, delayed speech and poor language skills. METHODS: In this article, a family with two affected fetuses presenting a mutation of the MCPH1 gene is reported. During the first trimester ultrasound of the second pregnancy, the measure of nuchal translucency was increased (NT = 3.1 mm) and, therefore, the risk for chromosomal abnormalities was high. Chorionic villi sampling (CVS) was then performed. Afterwards, fetal karyotyping and Next Generation Sequencing were carried out. Afterwards, NGS was also performed in a preserved sample of the first fetus which was terminated due to microcephaly. RESULTS: In this case, the fetuses had a novel homozygous mutation of the MCPH1 gene (c.348del). Their parents were heterozygous for the mutation. The fetuses showed severe microcephaly. Because of the splice sites in introns, this mutation causes the forming of dysfunctional proteins which lack crucial domains of the C-terminus. CONCLUSION: Our findings portray an association between the new MCPH1 mutation (c.348del) and the clinical features of autosomal recessive primary microcephaly (MCPH), contributing to a broader spectrum related to these pathologies. To our knowledge, this is the first prenatal diagnosis of MCPH due to a novel MCPH1 mutation.

Growth Hormone Deficiency due to p.(Gln467Argfs*64) Mutation in the ARID1B Gene in a Girl with Coffin-Siris Syndrome.

Introduction: Coffin-Siris syndrome (CSS) (MIM #135900) is an extremely rare genetic multisystemic disorder characterized by aplasia or hypoplasia of the upper phalanx of the fifth finger, moderate to severe cognitive and/or developmental delay, and characteristic facial features (thick lashes, hypertrichosis of the trunk, sparse hair). Congenital anomalies of the brain, kidney, and heart have been described but are less consistent across patients. Case presentation: We report a case of a 12-year-5-month-old girl with the clinical features of CSS, severe scoliosis, and epilepsy. Growth hormone deficiency was diagnosed at the age of 9 years. Recombinant human growth hormone (rhGH) treatment was started that resulted in a significant improvement of the growth velocity up to 5.4 cm/year (>90-97th centile). Next-generation sequencing identified a mutation in the ARID1B gene. Discusion: Despite its phenotypic heterogeneity, key features of CSS have become clearer and along with molecular diagnosis, a further global approach to improve the care of these individuals is enabled. Appropriate therapies for this population are needed to optimize growth and intellectual potentials.

Prenatal diagnosis of Baraitser - Winter syndrome using exome sequencing: Clinical report and review of literature.

Baraitser - Winter Cerebrofrontofacial Syndrome (BWCFF) is a rare disorder characterized by facial dysmorphism and mental retardation of varying grades. The clinical phenotype of BWCFF indicates variable phenotypic expression involving various congenital malformations such as cardiac, renal and musculoskeletal abnormalities. Nevertheless, the prenatal presentation of BWCFF is rarely described, making prenatal diagnosis challenging. This report describes a prenatal diagnosis of BWCFF syndrome to date; a case of a fetus with intrauterine growth restriction, increased nuchal fold, bilateral hydronerphosis, rocker bottom foot and clubfoot detected on Anomaly Scan is outlined. Molecular karyotype failed to detect any abnormality. Assessment with Next Generation Sequencing was then performed, revealing a heterozygous de novo mutation in ACTB gene setting the diagnosis of BWCFF.

Partial deletion of chromosome 6p causing developmental delay and mild dysmorphisms in a child: molecular and developmental investigation and literature search.

BACKGROUND: The interstitial 6p22.3 deletions concern rare chromosomal events affecting numerous aspects of both physical and mental development. The syndrome is characterized by partial deletion of chromosome 6, which may arise in a number of ways. CASE PRESENTATION: We report a 2.8-year old boy presenting with developmental delay and mild dysmorphisms. High-resolution oligonucleotide microarray analysis revealed with high precision a 2.5 Mb interstitial 6p deletion in the 6p22.3 region which encompasses 13 genes. CONCLUSIONS: Identification and in-depth analysis of cases presenting with mild features of the syndrome will sharpen our understanding of the genetic spectrum of the 6p22.3 deletion.

Novel Hemizygous Missense Variant of Spermine Synthase (SMS) Gene Causes Snyder-Robinson Syndrome in a Four-Year-Old Boy.

Snyder-Robinson syndrome (SRS) is an extremely rare X-linked intellectual disability syndrome (MRXSSR; MIM #309583). The main clinical features of SRS include psychomotor delay, hypotonia, and asthenic-type body habitus - reduced body weight and bone abnormalities (osteoporosis, fractures, kyphoscoliosis). We report a case of SRS with a hemizygous missense variant in the SMS gene,c.334C>G (p.Pro112Ala), in a 4-year-old boy, who initially developed hypotonia, delayed motor skills, and subsequently epilepsy. This variant in SMS was found to be de novo. To the best of our knowledge, this novel SMS gene variant has never been previously reported in disease-related variation databases, such as ClinVar or HGMD.

A novel heterozygous mutation in the SLC5A2 gene causing severe glycosuria, mild failure to thrive, and subclinical hypoglycemia.

Highlights A novel heterozygous mutation in the SLC5A2 gene in a 2-year-old girl with severe asymptomatic glycosuria, mild failure to thrive, and subclinical hypoglycemia: Continuous glucose monitoring identified 14% hypoglycemic excursions (< 70 mg/dl), reduced at 1% with 1 g/Kg uncooked cornstarch at bed-time milk and eliminated (0%) adjusting the dose at 1.5 g/Kg, as shown by Flash technology.

New Compound Heterozygous Splice Site Mutations of the Skeletal Muscle Ryanodine Receptor (RYR1) Gene Manifest Fetal Akinesia: A Linkage with Congenital Myopathies.

Mutations in the skeletal muscle ryanodine receptor (RYR1) gene have been linked to malignant hyperthermia susceptibility, central core disease, and minicore myopathy with external ophthalmoplegia. RYR1 is an intracellular calcium release channel and plays a crucial role in the sarcoplasmic reticulum and transverse tubule connection. Here, we report 2 fetuses from the same parents with compound heterozygous mutations in the RYR1 gene (c.10347+1G>A and c.10456-2Α>G) who presented with fetal akinesia and polyhydramnios at 27 and 19 weeks of gestation with intrauterine growth restriction in the third pregnancy. The prospective parents of the fetuses were heterozygous carriers for c.10456-2Α>G (mother) and c.10347+1G>A (father). Both mutations affect splice sites resulting in dysfunctional protein forms probably missing crucial domains of the C-terminus. Our findings reveal a new RYR1 splice site mutation (c.10456-2Α>G) that may be associated with the clinical features of myopathies, expanding the RYR1 spectrum related to these pathologies.

A novel familial mutation associated with Treacher Collins syndrome: A case report.

Treacher Collins syndrome (TCS) is a type of mandibulofacial dysostosis with incomplete penetrance and high intra- and interfamilial clinical heterogeneity, and it is associated with mutations of treacle ribosome biogenesis factor 1 (TCOF1), and RNA polymerase I and III subunit (POLR1)C and POLR1D genes. In the present case report, a patient with TCS with auricle dysplasia and hearing loss accompanied with intellectual disability is described. Sequence analysis was performed on blood samples from the patient and his father via oligonucleotide-based target capture, followed by next-generation sequencing. Alignment and variant calls were generated using the Burrows-Wheeler Aligner and Genome Analysis Toolkit, followed by bioinformatics analysis of the detected variants. A novel heterozygous mutation, c.911C>T (p.Ser304Leu), was detected in the TCOF1 gene, which was inherited from the father. The father of the patient only suffered from hearing loss. The present report is the first to identify an association between phenotypic variability and TCOF1 gene mutations and thus contributes to our understanding of the association between the genotype and phenotype in patients with TCS and offers clinically relevant information for diagnosis of the syndrome.

Targeted capture enrichment followed by NGS: development and validation of a single comprehensive NIPT for chromosomal aneuploidies, microdeletion syndromes and monogenic diseases.

BACKGROUND: Non-invasive prenatal testing (NIPT) has been widely adopted for the detection of fetal aneuploidies and microdeletion syndromes, nevertheless, limited clinical utilization has been reported for the non-invasive prenatal screening of monogenic diseases. In this study, we present the development and validation of a single comprehensive NIPT for prenatal screening of chromosomal aneuploidies, microdeletions and 50 autosomal recessive disorders associated with severe or moderate clinical phenotype. RESULTS: We employed a targeted capture enrichment technology powered by custom TArget Capture Sequences (TACS) and multi-engine bioinformatics analysis pipeline to develop and validate a novel NIPT test. This test was validated using 2033 cell-fee DNA (cfDNA) samples from maternal plasma of pregnant women referred for NIPT and paternal genomic DNA. Additionally, 200 amniotic fluid and CVS samples were used for validation purposes. All NIPT samples were correctly classified exhibiting 100% sensitivity (CI 89.7-100%) and 100% specificity (CI 99.8-100%) for chromosomal aneuploidies and microdeletions. Furthermore, 613 targeted causative mutations, of which 87 were unique, corresponding to 21 monogenic diseases, were identified. For the validation of the assay for prenatal diagnosis purposes, all aneuploidies, microdeletions and point mutations were correctly detected in all 200 amniotic fluid and CVS samples. CONCLUSIONS: We present a NIPT for aneuploidies, microdeletions, and monogenic disorders. To our knowledge this is the first time that such a comprehensive NIPT is available for clinical implementation.

Autism spectrum disorder, anxiety and severe depression in a male patient with deletion and duplication in the 21q22.3 region: A case report.

In this report, a patient carrying a 650 kb deletion and a 759 kb duplication of chromosomal 21q22.3 region was described. Facial dysmorphic features, hypotonia, short stature, learning impairment, autism spectrum disorder, anxiety and depression were observed clinical characteristics. Mentioned copy number variants were the shortest in length reported so far. The current study hypothesized that the presence of a susceptibility locus for autism spectrum disorder associated with depression and anxiety may be located in a 200 kb region between the PCNT and PRMT2 genes. The current study aimed to provide insight into the human genome morbidity map of chromosome 21.

17p13.1 Microduplication Syndrome in a Child, Familial Short Stature, and Growth Hormone Deficiency: A Case Report and Review of the Literature.

To date, 6 cases of 17p13.1 microduplications have been described in the literature. Intellectual disability is the core feature, together with minor facial dysmorphisms and obesity. We describe the first case of a young patient with a maternally inherited microduplication in 17p13.1 presenting with growth hormone deficiency. The boy was addressed to the endocrine division for growth retardation (weight and height <3rd percentile). Besides minor facial dysmorphisms, physical and neurological examinations were normal except for motor dyspraxia. Basic blood tests and endocrinological investigations were normal, but IGF1 levels were low for his age. Growth hormone deficiency was confirmed. Hypothalamic pituitary MRI was normal. His karyotype was 46XY. Array-CGH analysis detected a 422-kb copy number gain in the spanning region 17p13.1 inherited from his mother. Although familial short stature is considered a "normal" variation of growth retardation, hormonal and genetic investigation is essential in the etiological diagnosis.

A novel detrimental homozygous mutation in the WFS1 gene in two sisters from nonconsanguineous parents with untreated diabetes insipidus.

Given the limited lifespan and with the recent progress in experimental treatments for WS, timely diagnosis and multidisciplinary treatment for DI/DM, hydronephrosis, and visual/psychiatric status-maintaining quality of life-are of crucial importance.

Small supernumerary marker chromosomes: A legacy of trisomy rescue?

We studied by a whole genomic approach and trios genotyping, 12 de novo, nonrecurrent small supernumerary marker chromosomes (sSMC), detected as mosaics during pre- or postnatal diagnosis and associated with increased maternal age. Four sSMCs contained pericentromeric portions only, whereas eight had additional non-contiguous portions of the same chromosome, assembled together in a disordered fashion by repair-based mechanisms in a chromothriptic event. Maternal hetero/isodisomy was detected with a paternal origin of the sSMC in some cases, whereas in others two maternal alleles in the sSMC region and biparental haplotypes of the homologs were detected. In other cases, the homologs were biparental while the sSMC had the same haplotype of the maternally inherited chromosome. These findings strongly suggest that most sSMCs are the result of a multiple-step mechanism, initiated by maternal meiotic nondisjunction followed by postzygotic anaphase lagging of the supernumerary chromosome and its subsequent chromothripsis.

A Girl with 10 Mb Distal Xp Deletion Arising from Maternal Pericentric Inversion: Clinical Data and Molecular Characterization.

BACKGROUND: Short arm deletions of the X-chromosome are challenging issues for genetic counseling due to their low penetrance in population. Female carriers of these deletions have milder phenotype than male ones, considering the intellectual ability and social skills, probably because of the X-chromosome inactivation phenomenon. CASE REPORT: A female patient with a 10Mb distal Xp deletion and an Xq duplication, showing mild intellectual disability, is described in this report. While the deletion arose from a maternal pericentric inversion, the duplication was directly transmitted from the mother who is phenotypically normal. CONCLUSION: This report underlines the usefulness of molecular cytogenetic technics in postnatal diagnosis.