Seeing is believing: Correlating optoelectronic functionality with atomic scale imaging of single semiconductor nanocrystals.

A unique on-chip method for the direct correlation of optical properties, with atomic-scale chemical-structural characteristics for a single quantum dot (QD), is developed and utilized in various examples. This is based on performing single QD optical characterization on a modified glass substrate, followed by the extraction of the relevant region of interest by focused-ion-beam-scanning electron microscope processing into a lamella for high resolution scanning transmission electron microscopy (STEM) characterization with atomic scale resolution. The direct correlation of the optical response under an electric field with STEM analysis of the same particle allows addressing several single particle phenomena: first, the direct correlation of single QD photoluminescence (PL) polarization and its response to the external field with the QD crystal lattice alignment, so far inferred indirectly; second, the identification of unique yet rare few-QD assemblies, correlated directly with their special spectroscopic optical characteristics, serving as a guide for future designed assemblies; and third, the study on the effect of metal island growth on the PL behavior of hybrid semiconductor-metal nanoparticles, with relevance for their possible functionality in photocatalysis. This work, therefore, establishes the use of the direct on-chip optical-structural correlation method for numerous scenarios and timely questions in the field of QD research.

National Rapid Genome Sequencing in Neonatal Intensive Care.

Importance: National implementation of rapid trio genome sequencing (rtGS) in a clinical acute setting is essential to ensure advanced and equitable care for ill neonates. Objective: To evaluate the feasibility, diagnostic efficacy, and clinical utility of rtGS in neonatal intensive care units (NICUs) throughout Israel. Design, Setting, and Participants: This prospective, public health care-based, multicenter cohort study was conducted from October 2021 to December 2022 with the Community Genetics Department of the Israeli Ministry of Health and all Israeli medical genetics institutes (n = 18) and NICUs (n = 25). Critically ill neonates suspected of having a genetic etiology were offered rtGS. All sequencing, analysis, and interpretation of data were performed in a central genomics center at Tel-Aviv Sourasky Medical Center. Rapid results were expected within 10 days. A secondary analysis report, issued within 60 days, focused mainly on cases with negative rapid results and actionable secondary findings. Pathogenic, likely pathogenic, and highly suspected variants of unknown significance (VUS) were reported. Main Outcomes and Measures: Diagnostic rate, including highly suspected disease-causing VUS, and turnaround time for rapid results. Clinical utility was assessed via questionnaires circulated to treating neonatologists. Results: A total of 130 neonates across Israel (70 [54%] male; 60 [46%] female) met inclusion criteria and were recruited. Mean (SD) age at enrollment was 12 (13) days. Mean (SD) turnaround time for rapid report was 7 (3) days. Diagnostic efficacy was 50% (65 of 130) for disease-causing variants, 11% (14 of 130) for VUS suspected to be causative, and 1 novel gene candidate (1%). Disease-causing variants included 12 chromosomal and 52 monogenic disorders as well as 1 neonate with uniparental disomy. Overall, the response rate for clinical utility questionnaires was 82% (107 of 130). Among respondents, genomic testing led to a change in medical management for 24 neonates (22%). Results led to immediate precision medicine for 6 of 65 diagnosed infants (9%), an additional 2 (3%) received palliative care, and 2 (3%) were transferred to nursing homes. Conclusions and Relevance: In this national cohort study, rtGS in critically ill neonates was feasible and diagnostically beneficial in a public health care setting. This study is a prerequisite for implementation of rtGS for ill neonates into routine care and may aid in design of similar studies in other public health care systems.

[HOW SIMPLE IS "SIMPLE" GENETIC COUNSELING?]

INTRODUCTION: Genetic counselors are often compared with other medical professionals in terms of productivity, based on the number of patients seen and the time required for each patient. Prenatal genetic counseling before amniocentesis in uneventful pregnancies is considered to be a "simple" counseling, with potentially less time required for each patient. Thus, in some medical centers the duration of such consultations is limited to provide only the basic explanation without detailed collection of personal and family history, while in others the explanation is given to several patients together. AIMS: To assess the need for extended genetic counseling during supposedly "simple" genetic consultations before amniocentesis. METHODS: Data was collected from January 2018 until August 2020 of all patients undergoing genetic counseling before amniocentesis due to advanced maternal age, abnormal biochemical screening, or without medical indication. The consultations were given by four genetic counselors and two medical geneticists. The need for extended genetic counseling was evaluated based on pedigree and the discussion summaries and recommendations noted in genetic counseling summaries. RESULTS: Of the 1085 relevant counseling appointments, 657 (60.5%) required additional explanation beyond the basic consultation. The reasons for extended counseling included medical disorders of the woman or spouse (21.2%), carrier state for autosomal recessive diseases (18.6%), diagnosed or suspected genetic conditions of a child or previous pregnancy (9.6%), or medical disorders in the extended family (79.1%). In 31.0% of patients, recommended carrier screening tests were recommended or added. In 32.3% of cases, only one extra subject was counseled, in 16.3% two subjects, and in 5%, three subjects or more. The additional explanations were estimated as short (up to 5 minutes) in 36.9% of the cases, intermediate (5 to 15 minutes) in 59.9%, and long (over 15 minutes) in 2.6% of cases. The consultation's duration was not affected from it being a first meeting or a recurrent consultation. CONCLUSIONS: The need for further explanation was demonstrated in over 60% of genetic consultations, performed prior to amniocentesis due to supposedly "simple" indication. DISCUSSION: This fact reflects the importance of formal genetic counseling even in cases of seemingly simple indications, with an emphasis on detailed personal and family history, dedicating sufficient time to the counseling itself. Alternatively, it is important to exercise extra caution when conducting a short explanatory conversation prior to amniocentesis, including detailed questionnaires and the patient's signature on the possible limitations of such explanations.

The anxiety caused by abnormal results of Down syndrome screening tests.

The objective of our survey was to evaluate the anxiety experienced by women receiving abnormal results of prenatal Down syndrome screening by an electronic anonymous survey. Anxiety level was evaluated by a six-item Spielberger State-Trait Anxiety Inventory. Of 559 respondents, high anxiety scores were reported in the majority (86.0%). Higher anxiety scores were noted in women informed of the abnormal result by the caregiver vs. written answer. 59.1% of the respondents preferred the risk reported as percentage, while only 4.4% gave precedence to the current form (e.g. 1 in 100). The participants noted several factors which could relieve their anxiety, including an explanatory booklet (72.4%) or a website (77.9%). In conclusion, women receiving abnormal results of Down syndrome screening experience significant anxiety. Efforts should be made to relieve this distress, including changing the historical ratio risk format to percentage, adding a non-directive verbal annotation, an explanatory website and improving health professionals' understanding of the exact statistical meaning of the risk.Impact statementWhat is already known on this subject? Abnormal results of prenatal screening for Down syndrome might cause the women significant anxiety. Several simple methods are able to relieve this distress; however, they are frequently not implemented in the routine practice.What the results of this study add? We show that abnormal results of the screening tests are associated with high anxiety scores in the majority of women (86.0%). The majority of the respondents preferred the risk reported as percentage (vs. historical representation as a ratio). The participants noted several factors which could relieve their anxiety, including an explanatory booklet or a website.What the implications are of these findings for clinical practice and/or further research? Based on the results, we discuss the numerous ways able to available alleviate the distress.

Biallelic ADAM22 pathogenic variants cause progressive encephalopathy and infantile-onset refractory epilepsy.

Pathogenic variants in A Disintegrin And Metalloproteinase (ADAM) 22, the postsynaptic cell membrane receptor for the glycoprotein leucine-rich repeat glioma-inactivated protein 1 (LGI1), have been recently associated with recessive developmental and epileptic encephalopathy. However, so far, only two affected individuals have been described and many features of this disorder are unknown. We refine the phenotype and report 19 additional individuals harbouring compound heterozygous or homozygous inactivating ADAM22 variants, of whom 18 had clinical data available. Additionally, we provide follow-up data from two previously reported cases. All affected individuals exhibited infantile-onset, treatment-resistant epilepsy. Additional clinical features included moderate to profound global developmental delay/intellectual disability (20/20), hypotonia (12/20) and delayed motor development (19/20). Brain MRI findings included cerebral atrophy (13/20), supported by post-mortem histological examination in patient-derived brain tissue, cerebellar vermis atrophy (5/20), and callosal hypoplasia (4/20). Functional studies in transfected cell lines confirmed the deleteriousness of all identified variants and indicated at least three distinct pathological mechanisms: (i) defective cell membrane expression; (ii) impaired LGI1-binding; and/or (iii) impaired interaction with the postsynaptic density protein PSD-95. We reveal novel clinical and molecular hallmarks of ADAM22 deficiency and provide knowledge that might inform clinical management and early diagnostics.

Diagnostic yield and recognized barriers of an adult neurogenetics clinic.

The advent of molecular genetic technologies paved a path for the diagnosis of many neurological disorders. Joint evaluation by a neurologist and a medical genetics specialist can potentially increase diagnostic effectiveness by ensuring the exclusion of non-genetic conditions with similar phenotypes and by rationally selecting appropriate genetic diagnostic tools. Therefore, a monthly adult neurogenetics clinic was established. A retrospective review of medical records of all patients who attended the clinic from April 2015 to March 2019 was conducted. Eighty-two patients were evaluated (age: 47.1 ± 15.7, male: 37(45%), 42 (51%) had a positive family history). Disease duration was typically long (11.4 ± 0.9 years). Futile use of diagnostic modalities was very common (45 (55%) had repeated MRI, 28 (34%) hospitalized for observation in neurologic departments, 12 (14%) had a normal metabolic workup, 4 (5%) with a non-conclusive muscle biopsy, 1 with a normal cerebral angiography). Following clinical evaluation, molecular genetic testing was offered to 67 (82%) patients. In the other 15 (18%), routine workup for the exclusion of non-genetic conditions was not complete; obtainable information regarding family members was missing or that a neurogenetic disorder seemed improbable. Twenty-seven (33%) patients received a definitive diagnosis, either a genetic (23, 28%) or non-genetic (4, 5%). Excluding 4 cases of pre-symptomatic diagnosis, the diagnostic yield was 30%. The adherence to genetic testing recommendations was 62%. The reasons for non-adherence were lack of public funding for the required test (52%) and patient decision not to proceed (48%). Given the frequent futile use of diagnostic modalities, referral of non-genetic conditions with similar phenotypes among neurogenetic disorders, and the complexity of clinical genomic data analysis, a multi-disciplinary neurogenetics clinic seems justified.

A novel truncating variant in the FGD1 gene associated with Aarskog-Scott syndrome in a family previously diagnosed with Tel Hashomer camptodactyly.

Tel Hashomer camptodactyly syndrome is a long-known entity characterized by camptodactyly with muscular hypoplasia, skeletal dysplasia, and abnormal palmar creases. Currently, the genetic basis for this disorder is unknown, thus there is a possibility that this clinical presentation may be contained within another genetic diagnosis. Here, we present a multiplex family with a previous clinical diagnosis of Tel Hashomer camptodactyly syndrome. Whole exome sequencing and pedigree-based analysis revealed a novel hemizygous truncating variant c.269_270dup (p.Phe91Alafs*34) in the FGD1 gene (NM_004463.3) in all three symptomatic patients, congruous with a diagnosis of Aarskog-Scott syndrome. Our report adds to the limited data on Aarskog-Scott syndrome, and emphasizes the importance of unbiased comprehensive molecular testing toward establishing a diagnosis for genetic syndromes with unknown genetic basis.

The effect of polyhydramnios degree on chromosomal microarray results: a retrospective cohort analysis of 742 singleton pregnancies.

PURPOSE: To analyze the risk for clinically significant microarray aberrations in pregnancies with polyhydramnios. METHODS: Data from all chromosomal microarray analyses (CMA) performed due to polyhydramnios between January 2013 and December 2019 were retrospectively obtained from the Ministry of Health Database. The rate of clinically significant (pathogenic and likely pathogenic) CMA findings in isolated and non-isolated polyhydramnios cohorts was compared to a local control group of 5541 fetuses with normal ultrasound, in which 78 (1.4%) abnormal results were demonstrated. Subgroup analyses were performed by the degree of polyhydramnios, week of diagnosis, maternal age, and the presence of additional sonographic anomalies. RESULTS: In the isolated polyhydramnios cohort, 19/623 (3.1%) clinically significant CMA aberrations were noted, a significantly higher rate compared to the control population. However, the risk for abnormal CMA results in the 158 cases with mild polyhydramnios (AFI 25-29.9, or maximal vertical pocket 8-11.9 cm) did not significantly differ from pregnancies with normal ultrasound. Of 119 cases of non-isolated polyhydramnios (most frequently associated with cardiovascular (26.1%) and brain (15.1%) anomalies), 8 (6.7%) abnormal CMA findings were noted, mainly karyotype-detectable. CONCLUSION: Mild polyhydramnios was not associated with an increased rate of clinically significant microarray results, compared to pregnancies with normal ultrasound. An extensive anatomical sonographic survey should be performed in pregnancies with polyhydramnios, with consideration of fetal echocardiography.

A novel mutation in MYCN gene causing congenital absence of the flexor pollicis longus tendon as an unusual presentation of Feingold syndrome 1.

Feingold syndrome 1 (FGLDS1) is an autosomal dominant malformation syndrome, characterized by skeletal anomalies, microcephaly, facial dysmorphism, gastrointestinal atresias and learning disabilities. Mutations in the MYCN gene are known to be the cause of this syndrome. Congenital absence of the flexor pollicis longus (CAFPL) tendon is a rare hand anomaly. Most cases are sporadic and no genetic variants have been described associated with this abnormality. We describe here a pedigree combining familial CAFPL tendon as a feature of FGLDS1. Molecular analyses of whole exome sequence data in five affected family members spanning three generations of this family revealed a novel mutation in the MYCN gene (c.1171C>T; p.Arg391Cys). Variants in MYCN have not been published in association with isolated or syndromic CAFPL tendon, nor has this been described as a skeletal feature of Feingold syndrome. This report expands on the clinical and molecular spectrum of MYCN-related disorders and highlights the importance of MYCN protein in normal human thumb and foramen development.

Spectrum of genes for inherited hearing loss in the Israeli Jewish population, including the novel human deafness gene ATOH1.

Mutations in more than 150 genes are responsible for inherited hearing loss, with thousands of different, severe causal alleles that vary among populations. The Israeli Jewish population includes communities of diverse geographic origins, revealing a wide range of deafness-associated variants and enabling clinical characterization of the associated phenotypes. Our goal was to identify the genetic causes of inherited hearing loss in this population, and to determine relationships among genotype, phenotype, and ethnicity. Genomic DNA samples from informative relatives of 88 multiplex families, all of self-identified Jewish ancestry, with either non-syndromic or syndromic hearing loss, were sequenced for known and candidate deafness genes using the HEar-Seq gene panel. The genetic causes of hearing loss were identified for 60% of the families. One gene was encountered for the first time in human hearing loss: ATOH1 (Atonal), a basic helix-loop-helix transcription factor responsible for autosomal dominant progressive hearing loss in a five-generation family. Our results show that genomic sequencing with a gene panel dedicated to hearing loss is effective for genetic diagnoses in a diverse population. Comprehensive sequencing enables well-informed genetic counseling and clinical management by medical geneticists, otolaryngologists, audiologists, and speech therapists and can be integrated into newborn screening for deafness.

Genetic counseling of high-risk isolated populations: A worldwide challenge.

BACKGROUND: Isolated populations with high rates of consanguinity and genetic disorders can be found in most parts of the world. The aim of our paper was to highlight the unique challenges faced in genetic counseling for such patients and to discuss the ways to facilitate the difficulties, with an emphasis on the crucial role of electronic medical records (EMR). CASE: We report a couple presenting with elevated maternal alpha-fetoprotein in three pregnancies, in which an erroneous diagnosis of epidermolysis bullosa was established in the past and carried along through several years. The live born proband had no evidence of skin disease; however, soon after birth she was diagnosed with congenital nephrotic syndrome. Sequencing of NPHS1 gene yielded a homozygous likely pathogenic genetic variant c.2104G > A (p.Gly702Arg). Population screening performed in the village of residence revealed a carrier frequency of 1-47. This high frequency justified including testing for the founder genetic variant in the national program for population screening. CONCLUSIONS: Our report highlights the caution, suspicion and time investment which should be practiced and addressed in genetic counseling of high-risk isolated populations. Using EMR may facilitate reaching the correct diagnosis, enable accurate genetic counseling and provide information for decision-making to the couples, as well as "save" a large community from devastating diseases.

Activating MRAS mutations cause Noonan syndrome associated with hypertrophic cardiomyopathy.

The RASopathies are a group of genetic syndromes caused by upregulated RAS signaling. Noonan syndrome (NS), the most common entity among the RASopathies, is characterized mainly by short stature, cardiac anomalies and distinctive facial features. Mutations in multiple RAS-MAPK pathway-related genes have been associated with NS and related phenotypes. We describe two unrelated patients presenting with hypertrophic cardiomyopathy (HCM) and dysmorphic features suggestive of NS. One of them died in the neonatal period because of cardiac failure. Targeted sequencing revealed de novo MRAS variants, c.203C > T (p.Thr68Ile) and c.67G > C (p.Gly23Arg) as causative events. MRAS has only recently been related to NS based on the observation of two unrelated affected individuals with de novo variants involving the same codons here found mutated. Gly23 and Thr68 are highly conserved residues, and the corresponding codons are known hotspots for RASopathy-associated mutations in other RAS proteins. Functional analyses documented high level of activation of MRAS mutants due to impaired GTPase activity, which was associated with constitutive plasma membrane targeting, prolonged localization in non-raft microdomains, enhanced binding to PPP1CB and SHOC2 protein, and variably increased MAPK and PI3K-AKT activation. This report provides additional evidence that a narrow spectrum of activating mutations in MRAS represents another rare cause of NS, and that MRAS has to be counted among the RASopathy genes predisposing to HCM. Moreover, our findings further emphasize the relevance of the MRAS-SHOC2-PPP1CB axis in the control of MAPK signaling, and the contribution of both MAPK and PI3K-AKT pathways in MRAS functional upregulation.

A novel heterozygous loss-of-function DCC Netrin 1 receptor variant in prenatal agenesis of corpus callosum and review of the literature.

Agenesis of the corpus callosum (ACC) is a common prenatally-detected brain anomaly. Recently, an association between mutations in the DCC Netrin 1 receptor (DCC) gene and ACC, with or without mirror movements, has been demonstrated. In this manuscript, we present a family with a novel heterozygous frameshift mutation in DCC, review the available literature, and discuss the challenges involved in the genetic counseling for recently discovered disorders with paucity of medical information. We performed whole exome sequencing in a healthy nonconsanguineous couple that underwent two pregnancy terminations due to prenatal diagnosis of ACC. A heterozygous variant c.2774dupA (p.Asn925Lysfs*17) in the DCC gene was demonstrated in fetal and paternal DNA samples, as well as in a healthy 4-year-old offspring. When directly questioned, both father and child reported having mirror movements not affecting quality of life. Segregation analysis demonstrated the variant in three paternal siblings, two of them having mirror movements. Brain imaging revealed normal corpus callosum. Summary of literature data describing heterozygous loss-of-function variants in DCC (n = 61) revealed 63.9% penetrance for mirror movements, 9.8% for ACC, and 5% for both. No significant neurodevelopmental abnormalities were reported among the seven published patients with DCC loss-of-function variants and ACC. Prenatal diagnosis of ACC should prompt a specific anamnesis regarding any neurological disorder, as well as intentional physical examination of both parents aimed to detect mirror movements. In suspicious cases, detection of DCC pathogenic variants might markedly improve the predicted prognosis, alleviate the parental anxiety, and possibly prevent pregnancy termination.

The rare 13q33-q34 microdeletions: eight new patients and review of the literature.

The objective of this study is to shed light on the phenotype and inheritance pattern of rare 13q33-q34 microdeletions. Appropriate cases were retrieved using local databases of two largest Israeli centers performing CMA analysis. In addition, literature search in PubMed, DECIPHER and ClinVar databases was performed. Local database search yielded eight new patients with 13q33.1-q34 microdeletions (three of which had additional copy number variants). Combined with 15 cases detected by literature search, an additional 23 cases were reported in DECIPHER database, and 17 cases from ClinVar, so overall 60 patients with isolated 13q33.1-q34 microdeletions were described. Developmental delay and/or intellectual disability were noted in the vast majority of affected individuals (81.7% = 49/60). Of the 23 deletions involving the 13q34 cytoband only, in 3 cases, developmental delay and/or intellectual disability was not reported. Interestingly, in two of these cases (66.7%), the deletions did not involve the terminal CHAMP1 gene, as opposed to 3/20 (15%) of patients with 13q34 deletions and neurocognitive disability. Facial dysmorphism and microcephaly were reported in about half of the overall cases, convulsions were noted in one-fifth of the patients, while heart anomalies, short stature and hypotonia each involved about 10-30% of the cases. None of the 13q33-q34 deletions were inherited from a reported healthy parent. 13q33-q34 microdeletions are rare chromosomal aberrations, associated with high risk for neurodevelopmental disability. The rarity of this chromosomal aberration necessitates continuous reporting and collection of available evidence, to improve the ability to provide accurate genetic counseling, especially in the context of prenatal setting.

Whole-exome sequencing reveals a novel missense mutation in the MARS gene related to a rare Charcot-Marie-Tooth neuropathy type 2U.

Charcot-Marie-Tooth (CMT) is a heterogeneous group of progressive disorders, characterized by chronic motor and sensory polyneuropathy. This hereditary disorder is related to numerous genes and varying inheritance patterns. Thus, many patients do not reach a final genetic diagnosis. We describe a 13-year-old girl presenting with progressive bilateral leg weakness and gait instability. Extensive laboratory studies and spinal magnetic resonance imaging scan were normal. Nerve conduction studies revealed severe lower limb peripheral neuropathy with prominent demyelinative component. Following presumptive diagnosis of chronic inflammatory demyelinating polyneuropathy, the patient received treatment with steroids and intravenous immunoglobulins courses for several months, with no apparent improvement. Whole-exome sequencing revealed a novel heterozygous c.2209C>T (p.Arg737Trp) mutation in the MARS gene (OMIM 156560). This gene has recently been related to CMT type 2U. In-silico prediction programs classified this mutation as a probable cause for protein malfunction. Allele frequency data reported this variant in 0.003% of representative Caucasian population. Family segregation analysis study revealed that the patient had inherited the variant from her 60-years old mother, reported as healthy. Neurologic examination of the mother demonstrated decreased tendon reflexes, while nerve conduction studies were consistent with demyelinative and axonal sensory-motor polyneuropathy. Our report highlights the importance of next-generation sequencing approach to facilitate the proper molecular diagnosis of highly heterogeneous neurologic disorders. Amongst other numerous benefits, this approach might prevent unnecessary diagnostic testing and potentially harmful medical treatment.

Autosomal recessive Noonan syndrome associated with biallelic LZTR1 variants.

PURPOSE: To characterize the molecular genetics of autosomal recessive Noonan syndrome. METHODS: Families underwent phenotyping for features of Noonan syndrome in children and their parents. Two multiplex families underwent linkage analysis. Exome, genome, or multigene panel sequencing was used to identify variants. The molecular consequences of observed splice variants were evaluated by reverse-transcription polymerase chain reaction. RESULTS: Twelve families with a total of 23 affected children with features of Noonan syndrome were evaluated. The phenotypic range included mildly affected patients, but it was lethal in some, with cardiac disease and leukemia. All of the parents were unaffected. Linkage analysis using a recessive model supported a candidate region in chromosome 22q11, which includes LZTR1, previously shown to harbor mutations in patients with Noonan syndrome inherited in a dominant pattern. Sequencing analyses of 21 live-born patients and a stillbirth identified biallelic pathogenic variants in LZTR1, including putative loss-of-function, missense, and canonical and noncanonical splicing variants in the affected children, with heterozygous, clinically unaffected parents and heterozygous or normal genotypes in unaffected siblings. CONCLUSION: These clinical and genetic data confirm the existence of a form of Noonan syndrome that is inherited in an autosomal recessive pattern and identify biallelic mutations in LZTR1.

Microarray analysis in pregnancies with isolated unilateral kidney agenesis.

BackgroundThe objective of our study was to examine the risk for submicroscopic chromosomal aberrations among fetuses with apparently isolated solitary kidney.MethodsData acquisition was performed retrospectively by searching Israeli Ministry of Health-computerized database. All cases having chromosomal microarray analysis (CMA), referred because of an indication of isolated unilateral kidney agenesis between January 2013 and September 2016, were included. Rate of clinically significant CMA findings in these pregnancies was compared to pregnancies with normal ultrasound, based on a systematic review encompassing 9,792 cases and local data of 5,541 pregnancies undergoing CMA because of maternal request.ResultsOf the 81 pregnancies with isolated solitary kidney, 2 (2.47%) loss-of-copy number variants compatible with well-described deletion syndromes were reported (16p11.2-16p12.2 and 22q11.21 microdeletion syndromes). In addition, one variant of unknown significance was demonstrated. The relative risk for pathogenic CMA findings among pregnancies with isolated unilateral renal agenesis was not significantly different compared with the control population.ConclusionCMA analysis in pregnancies with unilateral renal agenesis might still be useful, to the same degree as it can be in the general population.

Whole-Exome Sequencing Identifies a Novel Homozygous Frameshift Mutation in the MTMR2 Gene as a Causative Mutation in a Patient with Charcot-Marie-Tooth Disease Type 4B1.

Charcot-Marie-Tooth (CMT) disease refers to a heterogeneous group of axonal and demyelinating polyneuropathies, characterized by chronic motor and sensory dysfunction. CMT is the most common genetic cause of neuropathy. The present study aimed to identify the gene mutation responsible for CMT in Ashkenazi Jew (AJ) patient. Genomic DNA was extracted from whole blood leukocytes of affected family and normal subject. Whole-exome sequencing was performed using the Illumina HiSeq2500. The DNA region containing the identified mutation was amplified by PCR and sequenced using dye-terminator chemistry and the forward primer. Physical examination of the patient revealed weakness and atrophy of the lower extremity muscles and Pes cavus foot deformity. Whole-exome sequencing indicated that the patient is homozygous for a novel frameshift mutation (c.1877_1878insAGAG, p.Arg630fs) in the myotubularin-related protein-2 gene (MTMR2), which resulted in an erroneous C-terminal sequence and extension by 15 amino acids. Patients' parents are healthy, and DNA sequencing analysis indicated that both are heterozygotes to the described mutation. The clinical feature of the patient may indicate a complete co-segregation of the p.Arg630fs mutation in MTMR2 gene with the CMT type 4B1 phenotype. Further studies are needed in order to estimate the prevalence of this mutation among AJ.

First-Trimester Crown-Rump Length and Risk of Chromosomal Aberrations-A Systematic Review and Meta-analysis.

IMPORTANCE: Lower than expected first-trimester crown-rump length (CRL) is a common sonographic finding, usually leading to reassessment of gestational age. OBJECTIVE: The aim of this study was to perform a meta-analysis defining the risk of chromosomal aberrations in pregnancies with decreased first-trimester CRL. EVIDENCE ACQUISITION: A search was conducted by a research librarian in 5 databases, with no time or language restrictions. Original researches examining the risk of chromosomal aberrations in pregnancies with low CRL were selected. The effect estimates were presented as odds ratios with 95% confidence intervals). RESULTS: Following screening of 3894 references, 12 articles were selected. Only 2 articles directly fulfilled the review goals, comparing the rates of chromosomal aberrations in small-CRL versus normal-CRL fetuses. Combined analysis of these 2 studies, encompassing a total of 403 fetuses with small CRL and 4047 control pregnancies, yielded an odds ratio of 5.54 (95% confidence interval, 1.2-26.1) for abnormal karyotype in small-CRL fetuses. Ten studies compared CRL in fetuses with specific chromosomal aberrations to pregnancies with normal karyotype, yielding a significant growth delay in fetuses with trisomy 18 (6 of 7 articles) and triploidy, but not in fetuses with trisomy 21. Overall quality of evidence was rated as "very low" using Grading of Recommendations Assessment, Development and Evaluation criteria. CONCLUSIONS AND RELEVANCE: Our review results indicate that low first-trimester CRL might be associated with a significantly increased risk of chromosomal anomalies. Thus, invasive prenatal testing or cell-free DNA screening might be offered in such pregnancies, particularly if dating is certain.

Risk for chromosomal aberrations in apparently isolated intrauterine growth restriction: A systematic review.

OBJECTIVE: To perform a systematic review examining the risk of chromosomal aberrations in apparently isolated intrauterine growth restriction (IUGR). METHODS: Search was conducted by research librarian in 5 databases. By independent screening of 2894 references, 2 investigators selected original studies examining the risk of chromosomal aberrations in apparently isolated IUGR diagnosed at the second and third trimesters by using ultrasound. We excluded studies describing IUGR combined with additional fetal anomalies detected by ultrasound and those where fetuses with structural anomalies or aneuploidy were not reported. RESULTS: Fourteen observational cohort studies were found, encompassing 874 apparently isolated IUGR cases. Mean rate of chromosomal aberrations was 6.4%, ranging between 0% (in 3 studies) and 26.3%. Only 2 articles examined apparently isolated IUGR diagnosed in the third trimester, encompassing a total of 32 pregnancies. Invasive testing of these cases yielded normal karyotypes. A single article analyzed 137 second trimester IUGR pregnancies, reporting 2 abnormal karyotypes of minimal clinical significance. Overall quality of existing evidence was defined as "very low." CONCLUSIONS: Due to a limited number of cases and insufficient quality of evidence, high-quality well standardized case-controlled trials should be conducted, further exploring the risk for chromosomal aberrations in pregnancies with isolated IUGR.