Standard Karyotype Research Articles

The Construction of a Standard Karyotype of Intermediate Wheatgrass and Its Potential Progenitor Species.

The genome composition of intermediate wheatgrass (IWG; Thinopyrum intermedium (Host) Barkworth and D.R. Dewey; 2n = 6x = 42) is complex and remains to be a subject of ongoing investigation. This study employed fluorescence in situ hybridization (FISH) to analyze the karyotype of Th. intermedium and its related species. With the St2-80 probe derived from Pseudoroegneria strigosa and the pDb12H probe from Dasypyrum breviaristatum, FISH analysis classified the chromosomes of Th. intermedium as JvsJvsJrJrStSt. FISH karyotype was established using pSc119.2-1, (GAA)10, AFA-3, AFA-4, pAs1-1, pAs1-3, pAs1-4, and pAs1-6 as a combined multiplex oligonucleotide probe. MATO software was used to analyze chromosome length, arm ratio, and karyotype structure. The karyotype formula of Th. intermedium is K(2n) = 6X = 42 = 36m + 6sm, and that of Th. junceiforme is K(2n) = 4X = 28 = 22m + 6sm. The karyotype formula of Th. elongatum and Th. bessarabicum is K(2n) = 2X = 14 = 12m + 2sm, of Ps. spicata is K(2n) = 2X = 14 = 2M + 12m, and of Da. villosum is K(2n) = 2X = 14 = 12m + 2sm. Based on the results of FISH, standard karyotypes of Th. intermedium and its potential progenitor species were constructed. These standard karyotypes revealed that there was evolutionary parallelism between genome and karyotype, but due to the complexity of evolution, the FISH signal of Th. intermedium was abundant and asymmetrical.

МАРКЕРНЫЕ ХРОМОСОМЫ В КОНСТИТУЦИОНАЛЬНОМ КАРИОТИПЕ: ПРОБЛЕМЫ ДИАГНОСТИКИ

The article discusses the problems of identifying, diagnosing, and assessing the clinical significance of marker chromosomes in the constitutional karyotype. Priority approaches in cytogenetic diagnostics are discussed, based on modern ideas about the mechanisms of formation, structure and main types of marker chromosomes, as well as the need for an integrated approach in diagnostics. Our own data on the effectiveness of standard karyotyping and molecular cytogenetic studies are presented.

The Value of Parental Karyotyping in Recurrent Pregnancy Loss Lies in Individual Risk Assessments.

Background and Objectives: Recurrent pregnancy loss (RPL) is a multifactorial condition, encompassing genetic, anatomical, immunological, endocrine, as well as infectious and environmental factors; however, the etiology remains elusive in a substantial number of cases. Genetic factors linked to RPL include parental karyotype abnormalities (e.g., translocations, inversions, copy number variants), an increase in sperm aneuploidy, fetal microchimerism, severe skewing of X chromosome inactivation, and various gene polymorphisms. Our study aims to explore the value of routine conventional parental karyotyping in couples with RPL. Materials and Methods: A total of 213 couples (426 individuals) with a history of RPL were enrolled in this retrospective study. The peripheral blood samples included in this study were referred to the Human Genomics Laboratory of the University of Medicine and Pharmacy in Craiova, Romania, for conventional cytogenetic analysis between January 2013 and December 2023, by the Outpatient Medical Genetics Clinic of the Emergency Clinical County Hospital of Craiova. Chromosome analysis was performed using standard protocols and karyotypes were reported according to ISCN. Results: Out of 426 patients provided with conventional G-banded chromosome analysis, 410 had a normal karyotype (96.2%) and 16 had chromosome abnormalities (3.8%). The most common chromosomal abnormalities were reciprocal and Robertsonian translocations, with chromosomes 8, 11, 14, and 21 being most frequently involved. A single numerical anomaly was detected (47,XYY). One or multiple chromosomal polymorphisms were identified in 104 subjects (24.4%). In addition, we conducted a stratified analysis of the unselected group and detected chromosome abnormalities in only four cases (0.94%). Conclusions: Our results are consistent with recommendations for paternal karyotyping after an individual risk assessment in instances such as a previous live birth with congenital anomalies and/or the detection of unbalanced chromosomes or a translocation in product of conception or chorionic villi/amniotic fluid samples. In the absence of a positive history, blindly karyotyping couples may prove too expensive and labor intensive, while providing no information on fertility status or live birth rates.

Epilepsy in a Moroccan patient with Pitt-Hopkins syndrome

Background : Pitt-Hopkins syndrome (PTHS) is a heterogeneous neurodevelopmental disorder, characterized by intellectual disability, distinctive facial features, and significant autonomic nervous system dysfunction. It is caused by variants in the transcription factor Tcf4. Methods/Observation : We report the first case of PTHS in Morocco, involving a 3-year-old child who presents with the typical features of PTHS, recurrent epilepsy, and a posterior fossa malformation consistent with Dandy-Walker syndrome, along with complete agenesis of the corpus callosum. Standard karyotype analysis and CGH-array confirmed the diagnosis, revealing a de novo terminal deletion of 27.894 kb on the long arm of chromosome 18. High-throughput sequencing is currently underway. Conclusion : Once PTHS is clinically suspected, the diagnosis should be confirmed through molecular genetic testing of the Tcf4 gene. Keywords : Pitt-Hopkins Syndrome, 18q deletion, Tcf4, de Novo, epilepsy.

New Insights on Chromosome Diversification in Malagasy Chameleons

In this work, we performed a preliminary molecular analysis and a comparative cytogenetic study on 5 different species of Malagasy chameleons of the genus Brookesia (B. superciliaris) and Furcifer (F. balteautus, F. petteri, F. major and F. minor). A DNA barcoding analysis was first carried out on the study samples using a fragment of the mitochondrial gene coding for the cytochrome oxidase subunit 1 (COI) in order to assess the taxonomic identity of the available biological material. Subsequently, we performed on the studied individuals a chromosome analysis with standard karyotyping (5% Giemsa solution at pH 7) and sequential C-banding + Giemsa, + CMA3, and + DAPI. The results obtained indicate that the studied species are characterized by a different chromosome number and a variable heterochromatin content and distribution, with or without differentiated sex chromosomes. In particular, B. superciliaris (2n = 36) and F. balteatus (2n = 34) showed a similar karyotype with 6 macro- and 12–11 microchromosome pairs, without differentiated sex chromosomes. In turn, F. petteri, F. major, and F. minor showed a karyotype with a reduced chromosome number (2n = 22–24) and a differentiated sex chromosome system with female heterogamety (ZZ/ZW). Adding our newly generated data to those available from the literature, we highlight that the remarkable chromosomal diversification of the genus Furcifer was likely driven by non-homologous chromosome fusions, including autosome–autosome, Z–autosome, and W–autosome fusions. The results of this process resulted in a progressive reduction in the chromosome number and partially homologous sex chromosomes of different shapes and sizes.

Turner Syndrome: An Update Review

Turner syndrome was first described by Oklahoman physician Henri Turner in 1938. This syndrome can occur in females who have an absent X chromosome, either completely or partially. The two primary forms of TS are mosaic and classical. Data from newborn genetic screening and epidemiology in the US, Europe, and Japan suggest that it affects 1% to 3% of live female infants. Webbed neck, swollen hands and feet, shield-shaped chest, low hairline, droopy eyelids, high- arched palate, and elevated elbow carrying angle are among the physical traits associated with TS. Standard karyotyping, which looks at the chromosomes of 30 peripheral cells, can confirm the presence of Turner syndrome. Cardiovascular irregularity, hypogonadotropic hypogonadism, infertility, skeletal abnormalities, and autoimmune illnesses are among the complications associated with TS. The main treatment for TS is growth hormone therapy, with different approaches based on the organ involved.

Diversity of Sex Chromosomes in Vertebrates: Six Novel Sex Chromosomes in Basal Haplochromines (Teleostei: Cichlidae).

African cichlid fishes are known for their high rates of phenotypic evolution. A rapid rate of diversification is apparent also in the diversity of their sex chromosomes. To date, sex determiners have been identified on 18 of 22 chromosomes in the standard karyotype. Here, we use whole-genome sequencing to characterize the sex chromosomes of seven populations of basal haplochromines, focusing on the genus Pseudocrenilabrus. We identify six new sex chromosome systems, including the first report of a cichlid sex-determining system on linkage group 12. We then quantify the rates and patterns of sex chromosome turnover in this clade. Finally, we test whether some autosomes become sex chromosomes in East African cichlids more often than expected by chance.

P-352 Investigating the association between DMPK CTG repeats and female hypogonadism in patients affected by Type 1 Myotonic Dystrophy

Abstract Study question Is DPKM CTG repeat size correlated with hypogonadism in female patients affected by type 1 Myotonic Dystrophy? Summary answer The size of CTG repeats in DPKM gene seems to be correlated with hypogonadism severity in female patients affected by type 1 Myotonic Dystrophy. What is known already Type 1 Myotonic Dystrophy (DMT1) is an autosomal dominant degenerative genetic disorder caused by CTG repeats in a single copy of DMPK gene. It is characterized by a broad phenotypic spectrum and a progressive course, involving primarily the muscular and endocrine systems. While DMT1 is a very well-known cause of male hypogonadism, the relationship between DMPK CTG repeats and female hypogonadism is almost unexplored yet. Study design, size, duration We performed a cross–sectional risk study in a cohort of 60 women, with a mean age of 31.5 years (18 to 45 years), referred to our Medical Genetics service for either suspected DMT1 or hypogonadism. The study duration was one year (from November 2022 to November 2023). Participants/materials, setting, methods We performed a DMPK–CTG analysis to investigate a possible correlation between CTG and hypogonadism. Based on the analysis, 11 women were diagnosed with DMT1 with associated hypogonadism, 11 with DMT1 without hypogonadism, 22 did not show DMPK expansion but were affected by hypogonadism, while the remaining 16 showed neither DMPK expansion nor hypogonadism. The patients affected by DMT1 performed standard karyotyping, FRAXA and FRAXE genetic testing to exclude alternative genetic causes of premature ovarian failure. Main results and the role of chance Our results, are indicative that the severity of hypogonadism in DMT1 patients may correlate with the size of CTG repeats. DMPK CTG repeats ranging from 150 – 1000 (range E2) were associated with milder forms of hypogonadism, while the patients having DMPK expansions within the E3 range (1000 CTG repeats or more) showed hypergonadotropic hypogonadism with both infertility and failure of medically assisted reproduction. Limitations, reasons for caution The female patients showing neither DMPK expansion nor hypogonadism did not perform other genetic analysis except DMPK-CTG testing. Moreover, due to the low sample size, our results did not reach statistical significance for a definitive conclusion. Wider implications of the findings To the best of our knowledge, this is the first study to show a possible correlation between female hypogonadism and DMPK CTG repeat size in female patients with type 1 myotonic dystrophy. These results, although preliminary, represent a first step in understanding a hitherto misrecognized clinical consequence of the disease. Trial registration number Not applicable

Comparative analysis of the application with the combination of CMA and karyotype in routine and late amniocentesis.

This is a retrospective comparative study. We aimed to analyze the results of karyotype and chromosomal microarray analysis (CMA) of amniotic fluid across different gestational weeks and evaluate the clinical value in prenatal diagnosis, particularly in the late pregnancies. Samples from 580 pregnant women of 18-23weeks of gestation (mid-gestation group) and 196 pregnant women of 24-32weeks of gestation (late group) were performed both standard G-band karyotype analysis and CMA. Among the 580 pregnant women in the routine group, the most common indications were positive Down's screening (213/580, 36.7%), followed by advanced maternal age (196/580, 33.8%); while fetal structural anomalies on ultrasonography were the top reason for amniocentesis in the late group (56/196, 28.6%). In the routine group, the total detection rate was 12.1% (70/580), of which 4.1% (24/580) were identified by karyotype analysis and 11.2% (65/580) by CMA. The total detection rate was 15.3% (30/196) in the late group, of which 5.1% (10/196) were detected by karyotype analysis, and 14.3% (28/196) by CMA. Karyotype analysis and CMA are complementary in detecting chromosomal abnormalities. Amniotic cavity puncture in the karyotype analysis in 18-23weeks of gestation and 24-32weeks of gestation is safe and effective, more obvious effect on the latter.

The likelihood of detecting abnormal karyotypes in fetuses with a single major anomaly or "soft" marker on ultrasonographic scanning.

Fetuses with abnormal karyotypes often exhibit distinctive ultrasonographic markers, including major anomalies and "soft" markers, indicating potential chromosomal issues. A crucial consideration arises when a single fetal anomaly is detected, raising the question of whether karyotyping is warranted, given the associated procedural risks. Our objective was to establish correlations between single fetal anomalies identified through ultrasound and chromosomal abnormalities. A cross-sectional study analyzed the karyotype of 1493 fetuses and detected a single ultrasonographic anomaly over a 16-year period. Karyotyping was performed using the standard karyotype technique. Moreover, data regarding the type of anomaly detected ultrasonographically, karyotype results, and outcomes following interventions were collected. Among other methods, the use of positive likelihood ratios (LR+) was used to evaluate the diagnostic accuracy of ultrasound compared to karyotyping. In total, an aberrant karyotype was identified in 99 fetuses (6.6%). This was most commonly observed in cases involving a "soft" marker, occurring in 27 out of 218 fetuses (12.4%). The most frequently detected aberrant karyotype resulted from aneuploidies (80.6% of cases), notably trisomy 21 (50.5%). "Soft" markers predicted chromosomal issues (LR+ = 1.9; OR = 2.4), and isolated polyhydramnios (LR+ = 1.54; OR = 1.6) showed significance in predicting fetal chromosomal aberrations. When assessing the necessity for karyotyping in fetuses with single major anomalies or "soft" markers, it is crucial to consider individual risks for chromosomopathies, including the LR+ of the detected marker. In cases where fetuses exhibit isolated anomalies with a normal karyotype, additional diagnostic measures, such as molecular cytogenetic and molecular genetics techniques, may become necessary.

Comparative Cytogenetics of the Malagasy Ground Geckos of the Paroedura bastardi and Paroedura picta Species Groups.

We present a comparative chromosome study of several taxa of the Malagasy ground geckos of the Paroedura bastardi and P. picta species groups. We employed a preliminary molecular analysis using a trait of the mitochondrial 16S rRNA gene (of about 570 bp) to assess the taxonomic status of the samples studied and a cytogenetic analysis with standard karyotyping (5% Giemsa solution), silver staining (Ag-NOR staining) and sequential C-banding (C-banding + Giemsa and + fluorochromes). Our results show that all the taxa studied of the P. bastardi group (P. ibityensis, P. rennerae and P. cf. guibeae) have a similar karyotype composed of 2n = 34 chromosomes, with two metacentric pairs (1 and 3) and all other pairs being acrocentric. Chromosome diversification in the P. bastardi group was mainly linked to the diversification of heteromorphic sex chromosome systems (ZZ/ZW) in P. ibityensis and P. rennerae, while no heteromorphic sex chromosome pair was found in P. cf. guibeae. The two taxa investigated of the P. picta species group (here named P. picta and P. cf. picta based on molecular data) showed the same chromosome number of 2n = 36, mostly acrocentric elements, but differed in the number of metacentric elements, probably as a result of an inversion at chromosome pair 2. We highlight that the genus Paroedura is characterized by the independent diversification of heterogametic sex chromosomes in different evolutionary lineages and, similarly to other phylogenetically related gecko genera, by a progressive formation of a biarmed element by means of tandem fusions and inversions of distinct pairs.

Evaluation the Application of Karyotype Analysis and Chromosome Microarray in Prenatal Diagnosis.

We aimed to compare the difference of the chromosomal abnormalities using karyotype analysis and chromosomal microarray (CMA) as well as to evaluate their application in different prenatal diagnosis indications. Overall, 3007 pregnant women with prenatal diagnosis indications from Medical Genetics Department of Linyi Women and Children's Health Care Hospital, who underwent standard G-banded karyotype analysis and CMA, were enrolled from 2018-2022. G-banded karyotype analysis and CMA were undergone simultaneously. All fetuses with genetic variants were enrolled for further analyzing. The frequency and differences of chromosomal abnormalities of the two methods were compared in different prenatal diagnosis indications groups. CMA improved 4.09% (123/3007) of genetic changes compared karyotype analysis. CMA is on par with karyotyping for detection of aneuploidies and gross unbalanced rearrangements. Serological screening and ultrasound abnormalities were the main indications of prenatal diagnosis. The detection rate of chromosomal abnormalities was highest in non-invasive prenatal testing (NIPT) abnormal group. In the ultrasound abnormality group, the detection rate of genetic variants in nuchal translucency (NT) increased group was higher than other subgroups and there was statistically significant difference in the detection rate of pCNVs. CMA can detect 5.57% (40/718) more genetic abnormalities in ultrasound abnormality group on the normal karyotype. CMA improved 0.67% (20/3007) of genetic changes with clinically significant compared karyotype, brought 3.42% (103/3007) of variants with uncertain significance (VOUS). CMA identified additional, clinically significant genetic variants on the basis of normal karyotype analysis, brought a proportion of unclear significant variants. All the pregnant women accepted amniocentesis should be informed about their characteristics of karyotype analysis and CMA by genetic counselors.

Absent or hypoplastic nasal bone: What to tell the prospective parents?

Absent or hypoplastic nasal bone (AHNB) on first or second-trimester ultrasonography (USG) is an important soft marker of Down syndrome. However, due to its varied incidence in euploid and aneuploid fetuses, there is always a dilemma of whether to go for invasive fetal testing for isolated AHNB. This study aims to assess outcomes specifically within the context of Indian ethnicity women. This was a prospective observational study. All patients who reported with AHNB in the first- or second-trimester USG were included. Genetic counseling was done, and noninvasive and invasive testing was offered. Chromosomal anomalies were meticulously recorded, and pregnancy was monitored. The incidence of AHNB in our study was 1.16% (47/4051). Out of 47 women with AHNB, the isolated condition was seen in 32 (0.78%) cases, while AHNB with structural anomalies was seen in nine cases (0.22%). Thirty-nine women opted for invasive testing. Six out of 47 had aneuploidy (12.7%), while two euploid cases (4.25%) developed nonimmune hydrops. The prevalence of Down syndrome in fetuses with AHNB was 8.5% (4/47) and 0.42% (17/4004) in fetuses with nasal bone present. This difference was statistically significant (p = .001). The results indicate that isolated AHNB cases should be followed by a comprehensive anomaly scan rather than immediately recommending invasive testing. However, invasive testing is required when AHNB is associated with other soft markers or abnormalities. As chromosomal microarray is more sensitive than standard karyotype in detecting chromosomal aberrations, it should be chosen over karyotype.

Trisomy 21-driven metabolite alterations are linked to cellular injuries in Down syndrome

Down syndrome (DS) arises from a genetic anomaly characterized by an extra copy of chromosome 21 (exCh21). Despite high incidence of congenital diseases among DS patients, direct impacts of exCh21 remain elusive. Here, we established a robust DS model harnessing human-induced pluripotent stem cells (hiPSCs) from mosaic DS patient. These hiPSC lines encompassed both those with standard karyotype and those carrying an extra copy of exCh21, allowing to generate isogenic cell lines with a consistent genetic background. We unraveled that exCh21 inflicted disruption upon the cellular transcriptome, ushering in alterations in metabolic processes and triggering DNA damage. The impact of exCh21 was also manifested in profound modifications in chromatin accessibility patterns. Moreover, we identified two signature metabolites, 5-oxo-ETE and Calcitriol, whose biosynthesis is affected by exCh21. Notably, supplementation with 5-oxo-ETE promoted DNA damage, in stark contrast to the protective effect elicited by Calcitriol against such damage. We also found that exCh21 disrupted cardiogenesis, and that this impairment could be mitigated through supplementation with Calcitriol. Specifically, the deleterious effects of 5-oxo-ETE unfolded in the form of DNA damage induction and the repression of cardiogenesis. On the other hand, Calcitriol emerged as a potent activator of its nuclear receptor VDR, fostering amplified binding to chromatin and subsequent facilitation of gene transcription. Our findings provide a comprehensive understanding of exCh21’s metabolic implications within the context of Down syndrome, offering potential avenues for therapeutic interventions for Down syndrome treatment.

First Cytogenetic Analysis of Hemidactylus mercatorius Gray, 1842 Provides Insights on Interspecific Chromosomal Diversification in the Genus Hemidactylus (Squamata: Gekkonidae).

This contribution provides the first karyotype description of Hemidactylus mercatorius and discusses the interspecific chromosome diversification in the genus. Chromosomal analysis was performed on samples from different Malagasy populations using standard karyotyping, Ag-NOR staining, and banding methods (sequential C-banding + Giemsa, + Chromomycin A3, +4',6-diamidino-2-phenylindole). Irrespective of sex or sampling locality, H. mercatorius shows a karyotype of 2n = 42 with metacentric (1, 18-21), submetacentric (4), subtelocentric (5, 11), and acrocentric pairs (all the remaining pairs). There was no heteromorphic chromosome pair and no clear distinction between macro- and microchromosomes. NORs were localised close to the centromeres of a medium acrocentric pair (14). Heterochromatic blocks were identified on the telomeric and centromeric regions of most chromosome pairs. A comparison with the karyotype of H. mabouia highlights that the different morphology of several chromosome pairs clearly distinguishes the two species, contrasting the previously proposed synonymy. The differences between the karyotypes of H. mercatorius and H. mabouia concern the number of biarmed and acrocentric elements, suggesting the occurrence of several chromosome inversions. Considering all the available karyotype data on Hemidactylus and its sister genus Cyrtodactylus, it is possible to advance an evolutionary hypothesis on their chromosomal evolution, starting from a common ancestor with 2n = 48 and all acrocentric elements. From this ancestral condition, the karyotype diversification in the two genera has been prevalently characterised by a progressive accumulation of fusions and inversions which have reduced the total chromosome count and increased the number of biarmed chromosomes.

A new tetraploid species of Tacinga (Cactaceae) from Ceará, Northeastern Brazil

Abstract A new species of cactus, Tacinga mirim (Cactaceae: Opuntioideae), is described and illustrated. Tacinga mirim is like a miniature version of T. palmadora, as far as is known, endemic to the state of Ceará, Northeastern Brazil. Although some populations of the new species have been known since 2009, they had been wrongly identified as T. palmadora. The description of the new species was made based on morphological and karyotypic analysis. Morphologically, it differs from T. palmadora by the much smaller size, semi-prostrate habit, smaller and deciduous stem-segments, lower density of spines, slightly larger and wide-open flowers, smooth pericarpel, and the globose to obovoid, purplish ripe fruit. The karyotype of T. mirim differs from T. palmadora in being tetraploid (not diploid), by presenting chromosomes that are twice as large, eight of which are submetacentric (differing from the fully metacentric standard karyotype of T. palmadora). The distribution of the new species is associated with the Caatinga of the crystalline basement of the northwestern hinterland of Ceará, found at relatively low altitudes (190-360 m). The IUCN category of threat for the new taxon was preliminary assessed. Both EOO and AOO indicate that the species is endangered (EN-B1-2ab).

Outcome of partial agenesis of corpus callosum

The diagnosis of corpus callosum anomalies by prenatal ultrasound has improved over the last decade because of improved imaging techniques, scanning skills, and the routine implementation of transvaginal neurosonography. Our aim was to investigate all cases of incomplete agenesis of the corpus callosum and to report the sonographic characteristics, the associated anomalies, and the perinatal outcomes. We performed a retrospective analysis of cases from January 2007 to December 2017 with corpus callosum anomalies, either referred for a second opinion or derived from the prenatal ultrasound screening program in a single tertiary referral center. Cases with complete agenesis were excluded from the analysis. Standardized investigation included a detailed fetal ultrasound including neurosonogram, fetal karyotyping (standard karyotype or array comparative genomic hybridization) and fetal magnetic resonance imaging. The pregnancy outcome was collected, and pathologic investigation in case of termination of the pregnancy or fetal or neonatal loss was compared with the prenatal findings. The pregnancy and fetal or neonatal outcomes were reported. The neurologic assessment was conducted by a pediatric neurologist using the Bayley Scales of Infant Development-II and the standardized Child Development Inventory when the Bayley investigation was unavailable. Corpus callosum anomalies were diagnosed in 148 cases during the study period, 62 (41.9%) of which were excluded because of complete agenesis, and 86 fetuses had partial agenesis (58.1%). In 20 cases, partial agenesis (23.2%) was isolated, whereas 66 (76.7%) presented with different malformations among which 29 cases (43.9%) were only central nervous system lesions, 21 cases (31.8%) were non-central nervous system lesions, and 16 cases (24.3%) had a combination of central nervous system and non-central nervous system lesions. The mean gestational age at diagnosis for isolated and non-isolated cases was comparable (24.29 [standard deviation, 5.05] weeks and 24.71 [standard deviation, 5.35] weeks, respectively). Of the 86 pregnancies with partial agenesis, 46 patients opted for termination of the pregnancy. Neurologic follow-up data were available for 35 children. The overall neurologic outcome was normal in 21 of 35 children (60%); 3 of 35 (8.6%) showed mild impairment and 6 of 35 (17.1%) showed moderate impairment. The remaining 5 of 35 (14.3%) had severe impairment. The median duration of follow-up for the isolated form was 45.6 months (range, 36-52 months) and 73.3 months (range, 2-138 months) for the nonisolated form. Partial corpus callosum agenesis should be accurately investigated by neurosonography and fetal magnetic resonance imaging to describe its morphology and the associated anomalies. Genetic anomalies are frequently present in nonisolated cases. Efforts must be taken to improve ultrasound diagnosis of partial agenesis and to confirm its isolated nature to enhance parental counseling. Although 60% of children with prenatal diagnosis of isolated agenesis have a favorable prognosis later in life, they often have mild to severe disabilities including speech disorders at school age and behavior and motor deficit disorders that can emerge at a later age.

Truncated vitronectin with E-cadherin enables the xeno-free derivation of human embryonic stem cells

Human embryonic stem cells (hESCs) have unique abilities that enable their use in cell therapy, disease modeling, and drug development. Their derivation is usually performed using a feeder layer, which is undefined and can potentially cause a contamination by xeno components, therefore there is a tendency to replace feeders with xeno-free defined substrates in recent years. Three hESC lines were successfully derived on the vitronectin with a truncated N-terminus (VTN-N) in combination with E-cadherin in xeno-free conditions for the first time, and their undifferentiated state, hESC morphology, and standard karyotypes together with their potential to differentiate into three germ layers were confirmed. These results support the conclusion that the VTN-N/E-cadherin is a suitable substrate for the xeno-free derivation of hESCs and can be used for the derivation of hESCs according to good manufacturing practices.

Chromosome evolution in Iberolacerta, a genus that deviates from the standard karyotype formula of Lacertidae

This paper describes the preparation of flow-sorted chromosome paints from the Iberian Rock lizard Iberolacerta monticola, exemplifying their subsequent use in cross-species comparisons of chromosome painting. We carried out comparative analyses of chromosome evolution in the congeneric species I. galani and I. bonnali, as well as in two other species of Lacertini (Lacerta schreiberi and Timon lepidus) whose sex chromosomes were also studied through comparative genomic hybridization. Most species of Lacertini possess a diplod number of 2n = 38, with 36 acrocentric macrochromosomes and 2 microchromosomes. However, the nine species included in the genus Iberolacerta do not possess microchromosomes. Furthermore, very conspicuous differences from the standard Lacertini karyotype were observed in the three Pyrenean species of this genus, which included several biarmed metacentrics and a Z1Z2W multiple sex-chromosome system. With the possible exception of L. schreiberi, all the species of the family Lacertidae described to date appear to share homologous Z chromosomes, which date back to the last common ancestor of the whole group. We provide conclusive evidence that L. schreiberi should no longer be considered an exception to this rule, and demonstrate that the loss of microchromosomes in Iberolacerta was produced by their fusion to a middle-sized chromosome. Furthermore, we show that the multiple sex-chromosome system of the Pyrenean species of Iberolacerta originated from the fusion of the ancestral W chromosome with one of the shortest autosomes, and provide additional evidence of the fast evolution of DNA sequences linked to the W chromosome in Lacertini.

Chromosome Diversity and Evolution of the Endemic Malagasy Velvet Geckos of the Genus Blaesodactylus (Reptilia, Gekkonidae).

We performed a molecular and phylogenetic analysis and a comparative cytogenetic study with standard karyotyping, silver staining (Ag-NOR) and sequential C-banding + Giemsa, + fluorochromes on several Blaesodactylus samples. The phylogenetic inference retrieved two main clades, the first comprises B. victori, B. microtuberculatus and B. boivini, while the second includes B. sakalava, B. antongilensis and B. ambonihazo. The available samples of B. sakalava form two different clades (here named B. sakalava clade A and clade B), which probably deserve a taxonomic re-evaluation. We found a karyological variability in Blaesodactylus in terms of chromosome number (2n = 40-42), morphology, location of NORs, and heterochromatin distribution pattern. Blaesodactylus antongilensis and B. sakalava clade A and B showed a karyotype of 2n = 40 mostly telocentric chromosomes. Pairs 1 and 6 were metacentric in B. sakalava clade A and B, while pair 1 was composed of subtelocentric/submetacentric elements in B. antongilensis. In contrast, B. boivini displayed a karyotype with 2n = 42 only telocentric chromosomes. NORs were on the first chromosome pair in B. boivini, and on the second pair in B. antongilensis. Adding our data to those available from the literature on evolutionarily related species, we highlight that the chromosome diversification in the genus probably proceeded towards a progressive reduction in the chromosome number and the formation of metacentric elements.