Opposite phenotypes of muscle strength and locomotor function in mouse models of partial trisomy and monosomy 21 for the proximal Hspa13-App region.

The trisomy of human chromosome 21 (Hsa21), which causes Down syndrome (DS), is the most common viable human aneuploidy. In contrast to trisomy, the complete monosomy (M21) of Hsa21 is lethal, and only partial monosomy or mosaic monosomy of Hsa21 is seen. Both conditions lead to variable physiological abnormalities with constant intellectual disability, locomotor deficits, and altered muscle tone. To search for dosage-sensitive genes involved in DS and M21 phenotypes, we created two new mouse models: the Ts3Yah carrying a tandem duplication and the Ms3Yah carrying a deletion of the Hspa13-App interval syntenic with 21q11.2-q21.3. Here we report that the trisomy and the monosomy of this region alter locomotion, muscle strength, mass, and energetic balance. The expression profiling of skeletal muscles revealed global changes in the regulation of genes implicated in energetic metabolism, mitochondrial activity, and biogenesis. These genes are downregulated in Ts3Yah mice and upregulated in Ms3Yah mice. The shift in skeletal muscle metabolism correlates with a change in mitochondrial proliferation without an alteration in the respiratory function. However, the reactive oxygen species (ROS) production from mitochondrial complex I decreased in Ms3Yah mice, while the membrane permeability of Ts3Yah mitochondria slightly increased. Thus, we demonstrated how the Hspa13-App interval controls metabolic and mitochondrial phenotypes in muscles certainly as a consequence of change in dose of Gabpa, Nrip1, and Atp5j. Our results indicate that the copy number variation in the Hspa13-App region has a peripheral impact on locomotor activity by altering muscle function.

8q13.1-q13.2 deletion associated with inferior cerebellar vermian hypoplasia and digital anomalies: a new syndrome?

BACKGROUND: Cerebellar vermis hypoplasia has been associated with a large number of chromosomal abnormalities and metabolic disorders, with few candidate genes clearly linked to isolated cerebellar vermis hypoplasia. PATIENT DESCRIPTION: We describe on a 12-year-old boy with inferior vermian hypoplasia associated with a novel de novo microdeletion. He presented with intellectual, speech and language impairment, unilateral facial nerve weakness, marked constipation, and bilateral hand and foot anomalies that were not consistent with any previously described syndrome. His hand features were digital reductions similar to those seen in 4q34 deletion syndrome, known as the "tale of the nail" sign. Cranial magnetic resonance imaging demonstrated isolated inferior cerebellar vermis hypoplasia. RESULTS: A de novo 1.4 Mb interstitial deletion was identified at 8q13.1-q13.2 on chromosomal microarray. This copy number variant involves 18 human genome reference sequence genes, with 11 Mendelian Inheritance in Man genes. Homozygous mutations in one of these genes (CSPP1) has recently been recently described as causing Joubert syndrome. CONCLUSION: We propose that the constellation of clinical features in this child represents a novel microdeletion syndrome and hypothesize that CSPP1 or other genes within the deleted region contribute to the cerebellar development.

Cognition and hippocampal plasticity in the mouse is altered by monosomy of a genomic region implicated in Down syndrome.

Down syndrome (DS) is due to increased copy number of human chromosome 21. The contribution of different genetic regions has been tested using mouse models. As shown previously, the Abcg1-U2af1 genetic region contributes to cognitive defects in working and short-term recognition memory in Down syndrome mouse models. Here we analyzed the impact of monosomy of the same genetic interval, using a new mouse model, named Ms2Yah. We used several cognitive paradigms and did not detect defects in the object recognition or the Morris water maze tests. However, surprisingly, Ms2Yah mice displayed increased associative memory in a pure contextual fear-conditioning test and decreased social novelty interaction along with a larger long-term potentiation recorded in the CA1 area following stimulation of Schaffer collaterals. Whole-genome expression studies carried out on hippocampus showed that the transcription of only a small number of genes is affected, mainly from the genetic interval (Cbs, Rsph1, Wdr4), with a few additional ones, including the postsynaptic Gabrr2, Gabbr1, Grid2p, Park2, and Dlg1 and the components of the Ubiquitin-mediated proteolysis (Anapc1, Rnf7, Huwe1, Park2). The Abcg1-U2af1 region is undeniably encompassing dosage-sensitive genes or elements whose change in copy number directly affects learning and memory, synaptic function, and autistic related behavior.

Partial trisomy 3p and partial monosomy 11q associated with double outlet right ventricle and septum pellucidum et vergae: a case report.

Su Partial trisomy 3p and partial monosomy 11q are rare chromosomal disorders with a deletion of part of chromosome 11 combined with a duplication of part of chromosome 3. These are usually inherited from a parent who carries a balanced translocation involving chromosome 3, which can result in the unbalanced translocation trisomy 3p in a child. In this paper, we report a newborn who has dysmorphic facial features, double outlet right ventricle, hypotonia, hypospadias, neonatal thrombocytopenia, hydroureteronephrosis, talipes equinovarus and septum pellucidum et vergae. Cytogenetic investigation revealed 46,XY,der(11)t(3;11)(p22.2;q23.3) and the karyotype of his father showed a balanced translocation, 46XY,t(3;11)(p22.2;p23.3).

Complete monosomy mosaic of chromosome 21: case report and review of literature.

Complete monosomy mosaic of chromosome 21 is a rare disorder. The syndromic features are highly variable. This study describes a girl of Mexican origin with complete monosomy 21 in mosaicism with novel findings, including cortical atrophy, macrostomia, pectum excavatum and immune deficiencies. Parental karyotypes were normal. FISH analysis with probes from 21q22.1-q22.2 region and centromere of X DNA probe was performed on peripheral blood lymphocytes whereas 21q22.1-q22.2 and 21q, 4p, 4q subtelomeric DNA probes were tested in fibroblasts. We propose that the monosomy 21 mosaicism is the cause of the survival of children with more than 4 months of age.

Neurocognitive functioning of a child with partial trisomy 6 and monosomy 21.

This case study describes the neurocognitive presentation of a child with identified genetic abnormalities of trisomy 6 and monosomy 21 who was evaluated as part of a standard medical protocol for cochlear implantation following diagnosis of profound sensorineural hearing loss. This child received neurocognitive testing prior to cochlear implantation and approximately 12 months post-activation of his cochlear implant. While he has not fully developed oral language, his presentation suggested improvement in overall skills since the activation of the cochlear implant; however, less than would be expected for a typically developing child.

El envejecimiento en el síndrome de Down: Dyrk1A como gen candidato para el declive cognitivo / Ageing in down syndrome: DYRK1A as a candidate gene for cognitive decline

Hemos centrado esta revisión en el trabajo realizado con el objetivo de determinar el papel del gen DYRK1A en el proceso degenerativo presente en el síndrome deDown (SD), y sus mecanismos patogenéticos, utilizandocomo aproximación experimental modelos de ratón genéticamente modificados con diferente dosis de este gen.En base a estos resultados, proponemos que Dyrk1A esun gen dosis-sensible que, por su patrón de expresión ypor los sustratos de fosforilación identificados, podríaparticipar en las alteraciones motoras, cognitivas y elproceso neuropatológico tipo enfermedad de Alzheimeren personas con SD (AU)

The DYRK1A gene has been implicated in the degenerative process observed in Down syndrome; however,its precise role and pathogenetic mechanisms are stillunclear. This paper reviews experimental work conducted in genetically modified mice with differing doses ofthe gene. The results suggest that DYRK1A is a dose sensitive gene that may participate in motor and cognitive disturbances and in Alzheimer-like neuropathologic processes in persons with Down syndrome, according tothe gene’s expression pattern and the phosphorylation substrates identified (AU)

Hearing loss in Turner syndrome.

OBJECTIVE: To address the characteristics of hearing loss in patients with Turner syndrome (TS), we evaluated hearing levels of patients with TS and analyzed causative factors. STUDY DESIGN: Thirty-three patients with TS (8 to 40 years of age) were studied through the use of audiological measurements, and causative factors were explored. RESULTS: Twenty cases (35 of 66 ears tested) showed high-frequency (8 kHz) sensory neural hearing loss (HFQ-SNHL). Fifteen cases (26 ears) and 15 cases (24 ears) of the impaired 20 cases were unresponsive to distortion-product otoacoustic emissions and transient-evoked otoacoustic emissions, respectively. HFQ-SNHL showed little relation to the history of middle ear infection and puberty, although middle ear infections were seen in 11 of the 20 cases. The hearing thresholds at high frequencies were correlated with age and body height (P < .001). The age-dependent increase in hearing thresholds in the high frequencies was more apparent in patients with TS with monosomic 45, X than in those with the mosaic type (P < .05). CONCLUSIONS: More than 60% of patients with TS had HFQ-SNHL. Because the increase in hearing threshold at high frequencies was shown to depend on karyotype and aging, regular otological examination is important for the determination of proper treatment.

Hidrops fetal no inmune: presentación de un caso y revisión de la literatura / No immune fetal hydrops: a case report and literature review

El hidrops fetal no inmune (HFNI) es una importante causa de pérdida perinatal, con mortalidad que varía entre 50-100 por ciento. El HFNI es una condición causada por un grupo heterogéneo de patologías. La fisiopatología del desorden que lo produce se conoce en muchos casos. Sin embargo, existen muchos casos en que la causa no se puede detérminar. Presentar un caso de hidrops fetal no inmune, el estudio realizado y la revisión de la literatura. Un caso de hidrops fetal no inmune, fue diagnósticado por ultrasonido antenatal a las 298 semanas de gestación. El feto murió al nacer, el cariotipo de muestra de sangre obtenida del cordón umbilical fue anormal. El examen postmorten fue compatible con Síndrome de Tuner e Higroma Quístico. En el presente caso el HFNI fue causado por la cromosomopatía tipo monosomía X y la anatomía linfática denominada higroma quístico. Todos los casos de HFNI deben ser evaluados prenatalmente para un adecuado diagnóstico y tratamiento cuando la mortalidad es prevenible.

Sporadic aneuploidy in PHA-stimulated lymphocytes of Turner's syndrome patients.

In line with the view that aneuploidy destabilizes the karyotype, initiating an autocatalytic process that gives rise to further loss and/or gain of chromosomes, we examined whether a constitutional aneuploidy such as monosomy for one chromosome is associated with sporadic loss and/or gain of other chromosomes. We used PHA-stimulated lymphocytes from eight women with Turner's syndrome (six displayed X chromosome monosomy ranging from 60.2% to 97.9%, and two were below 10%), and eight healthy women who served as a control group. Fluorescence in-situ hybridization (FISH), applied at interphase, was used to evaluate the level of aneuploidy for three randomly selected chromosomes (autosomes 8, 15 and 18) in each sample. For each tested chromosome, our results showed a significantly higher level of aneuploid cells in the samples from patients than in those from controls (p < 0.01). The mean level of aneuploid cells for all three tested autosomes was almost twice as high in the patient samples as in the control samples (p < 0.002). It is noteworthy that, in the Turner's syndrome patients, X chromosome disomic cells also displayed increased levels of aneuploidy. It is possible that monosomy of X chromosome in female cells destabilizes their own genome and also affects X disomic cells in the region. One may also speculate that a common factor(s) is involved with both constitutional and sporadic aneuploidy.

Haunting appearance of bcr/abl fusion gene products in a patient with therapy related leukaemia.

A 81-year-old man was diagnosed as multiple myeloma and had received melphalan for 6 years. After that, he developed acute myeloid leukemia (AML) with monosomy 7 and minor bcr/abl transcripts. Fluorescence in situ hybridization identified no detectable level of bcr/abl rearrangement. During chemotherapy for AML, minor bcr/abl transcripts disappeared and instead major bcr/abl transcripts emerged. He died of pneumonia 3 months later. At that time, neither minor nor major bcr/abl transcripts were seen. These observations suggest that certain therapy related leukemia may be susceptible to generate very small clones with bcr/abl rearrangements.

Effects on fear reactivity in XO mice are due to haploinsufficiency of a non-PAR X gene: implications for emotional function in Turner's syndrome.

Recent work has indicated altered emotional functioning in Turner's syndrome (TS) subjects (45,XO). We examined the role of X-chromosome deficiency on fear reactivity in X-monosomic mice (39,XO), and found that they exhibited anxiogenic behaviour relative to normal females (40,XX). A molecular candidate for this effect is Steroid sulfatase (Sts) as this is located in the pseudoautosomal region (PAR) of the X-chromosome and consequently is normally biallelically expressed. In addition, the steroid sulfatase enzyme (STS) is putatively linked to fear reactivity by an effect on GABAA receptors via the action of neurosteroids. Real-time PCR demonstrated that levels of Sts mRNA were reduced by half in the brains of 39,XO mice compared with 40,XX, and that expression levels of a number of GABAA subunits previously shown to be important components of fear processing (Gabra3, Gabra1 and Gabrg2) were also altered. However, 40,XY*X mice, in which the Y*X is a small chromosome comprising of a complete PAR and a small non-PAR segment of the X-chromosome, exhibited the same pattern of fear reactivity behaviour as 39,XO animals, but equivalent expression levels of Sts, Gabra1, Gabra3 and Gabrg2 to 40,XX females. This showed that although Sts may cause alterations in GABAA subunit expression, these changes do not result in increased fear reactivity. This suggests an alternative X-chromosome gene, that escapes inactivation, is responsible for the differences in fear reactivity between 39,XO and 40,XX mice. These findings inform the TS data, and point to novel genetic mechanisms that may be of general significance to the neurobiology of fear.

Morphology of the 45,X embryo: an embryoscopic study.

The morphology of monosomy X in embryos was documented by means of transcervical embryoscopy prior to evacuation in 24 cases of missed abortion. The embryos ranged in size from 13 mm to 26 mm CRL and were all developed beyond the sixth week of development. The embryonic phenotype varied from nearly normal to obviously abnormal with a combination of localized external developmental defects consisting of microcephaly, facial dysplasia, and retarded limb development. A single case of encephalocele was observed. The factors responsible for the wide range of developmental defects observed in monosomy X embryos are currently unknown. Transcervical embryoscopy can serve as a central component for further genetic studies elucidating these mechanisms which are needed for reaching a further understanding of the developmental effects of specific aneuploidy in human morphogenesis.

Sex-determining gene(s) on distal 9p: clinical and molecular studies in six cases.

We report on clinical and molecular findings in five karyotypic males (cases 1-5) and one karyotypic female (case 6) with distal 9p monosomy. Cases 1-3 and 6 had female external genitalia, case 4 showed ambiguous external genitalia, and case 5 exhibited male external genitalia with left cryptorchidism and right intrascrotal testis. Gonadal explorations at gonadectomy in cases 3 and 4 revealed that case 3 had left streak gonad and right agonadism, and case 4 had bilateral hypoplastic testes. Endocrine studies in cases 1-4 and 6 showed that cases 1, 3, and 6 had definite primary hypogonadism, with basal FSH levels of 54, 39, and 41 IU/L, respectively, whereas case 2 with severe malnutrition was unremarkable for the baseline values, and case 4 had fairly good testicular function. Fluorescence in situ hybridization and microsatellite analyses demonstrated that all cases had hemizygosity of the 9p sex-determining region distal to D9S1779, with loss of the candidate sex-determining genes DMRT1 and DMRT2 from the abnormal chromosome 9. Sequence analysis in cases 1-4 and 6 showed that they had normal sequences of each exon of DMRT1 and the DM domain of DMRT2 on the normal chromosome 9, and that cases 1-4 had normal SRY sequence. The results provide further support for the presence of a sex-determining gene(s) on distal 9p and favor the possibility of DMRT1 and/or DMRT2 being the sex-determining gene(s). Furthermore, as hemizygosity of the 9p sex-determining region was associated with a wide spectrum of gonadogenesis from agonadism to testis formation in karyotypic males and with primary hypogonadism regardless of karyotypic sex, it is inferred that haploinsufficiency of the 9p sex-determining gene(s) primarily hinders the formation of indifferent gonad, leading to various degrees of defective testis formation in karyotypic males and impaired ovary formation in karyotypic females.

Granulocyte colony-stimulating factor (G-CSF) dependent hematopoiesis with monosomy 7 in a patient with severe aplastic anemia after ATG/CsA/G-CSF combined therapy.

We report a case of secondary myelodysplastic syndrome (MDS) with monosomy 7, which evolved from severe aplastic anemia (SAA) after long-term use of granulocyte colony-stimulating factor (G-CSF). A 36 year old female was admitted for detailed examination and treatment of pancytopenia. SAA was diagnosed based on hypoplastic bone marrow and a normal chromosome study. She was treated with anti-thymocyte globulin (ATG), ciclosporin A (CsA) and G-CSF, which resulted in gradual improvement of not only the myeloid but also the erythroid-megakaryocyte series. However, bone marrow dysplasia with monosomy 7 was observed after 7 months of a combination therapy of immunosuppressant and G-CSF, which prompted the discontinuation of G-CSF administration. Thereafter, bone marrow hypoplasia gradually progressed, resulting in a second aplastic crisis. During this process, the proportion of marrow cells showing monosomy 7 decreased, and the proportion with normal karyotype increased. Re-administration of G-CSF induced a trilineage, though dysplastic, hematological response; but the monosomy 7 positive population increased again. These observations indicated the presence of G-CSF dependent hematopoiesis associated with monosomy 7 in this patient. Although many G-CSF related MDS/AML cases with this leukemia-specific abnormal karyotype have been reported with emphasis on the harmful effects of G-CSF, G-CSF was useful even after the appearance of monosomy 7 as a means of avoiding life-threatening infection in this patient.

Monosomy 1p is correlated with enhanced in vivo glucose metabolism in meningiomas.

The 2-[18F]fluoro-2-deoxy-D-glucose (FDG) uptake of 25 human meningiomas was preoperatively evaluated in vivo by positron-emission tomography (PET). After surgery, meningioma biopsies were analyzed cytogenetically. Five meningiomas showed partial monosomy for chromosome 1p additional to other typical chromosome aberrations. This aberrant karyotype was correlated with increased FDG uptake. Three of five meningiomas with monosomy 1p were classified as grade II according to WHO, while only one of 20 tumors without monosomy 1p was classified as grade II. Thus, monosomy 1p and elevated FDG uptake in PET are to be regarded as cytogenetic and metabolic parameters for the aggressiveness of meningiomas.

Interphase cytogenetics by fluorescent in situ hybridization (FISH) for characterization of monosomy-7-associated myeloid disorders.

By circumventing the need for metaphase preparations, fluorescent in situ hybridization (FISH) on interphase nuclei using chromosome-specific probes is a promising tool for the study of numerical chromosome aberrations not only in proliferating, but also in non-dividing cells. We analyzed 15 cases of monosomy-7-associated myeloid disorders with a biotinylated probe to the (peri)centromeric region of chromosome 7. Monosomy 7 was readily confirmed in all cases during active disease. In two patients only a minority of nuclei was monosomic, whereas cytogenetics had shown all metaphases to be missing one chromosome 7. FISH in one of them was able to identify a small marker chromosome as isolated pericentromeric region of chromosome 7. Minimal residual disease however could not be detected in three remission samples analyzed, as percentages of disomic nuclei were within the range of normal controls (96.8% 2.1%). In order to determine lineage involvement of the monosomic clone, a recent technique combining immunophenotyping and FISH (FICTION) was performed in one patient with AML after MPD. Monosomy 7 was found in virtually all myelomonocytic and erythroid cells (as discriminated by lineage-specific antibodies), in a part of CD34-positive precursor cells, but not in lymphocytes. We conclude that monosomy 7 in this patient is restricted to an early committed progenitor cell capable of erythroid and myelomonocytic differentiation.