Understanding surface reactivity of Si electrodes in Li-ion batteries by in operando scanning electrochemical microscopy.

In operando SECM is employed to monitor the evolution of the electrically insulating character of a Si electrode surface during (de-)lithiation. The solid-electrolyte interface (SEI) formed on Si electrodes is shown to be intrinsically electrically insulating. However, volume changes upon (de-)lithiation lead to the loss of the protecting character of the initially formed SEI.

Behavioral phenotypes in males with XYY and possible role of increased NLGN4Y expression in autism features.

The male sex chromosome disorder, 47,XYY syndrome (XYY), is associated with increased risk for social-emotional difficulties, attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). We hypothesize that increased Y chromosome gene copy number in XYY leads to overexpression of Y-linked genes related to brain development and function, thereby increasing risk for these phenotypes. We measured expression in blood of two Y genes NLGN4Y and RPS4Y in 26 boys with XYY and 11 male controls and evaluated whether NLGN4Y expression correlates with anxiety, ADHD, depression and autistic behaviors (from questionnaires) in boys with XYY. The XYY cohort had increased risk of ASD behaviors on the social responsiveness scale (SRS) and increased attention deficits on the Conners' DSM-IV inattention and hyperactive scales. In contrast, there was no increase in reported symptoms of anxiety or depression by the XYY group. Peripheral expression of two Y genes in boys with XYY vs. typically developing controls was increased twofold in the XYY group. Results from the SRS total and autistic mannerisms scales, but not from the attention, anxiety or depression measures, correlated with peripheral expression of NLGN4Y in boys with XYY. Males with XYY have social phenotypes that include increased risk for autism-related behaviors and ADHD. Expression of NLGN4Y, a gene that may be involved in synaptic function, is increased in boys with XYY, and the level of expression correlates with overall social responsiveness and autism symptoms. Thus, further investigation of NLGN4Y as a plausible ASD risk gene in XYY is warranted.

Clinical and molecular evaluation of SHOX/PAR1 duplications in Leri-Weill dyschondrosteosis (LWD) and idiopathic short stature (ISS).

CONTEXT: Léri-Weill dyschondrosteosis (LWD) is a skeletal dysplasia characterized by disproportionate short stature and the Madelung deformity of the forearm. SHOX mutations and pseudoautosomal region 1 deletions encompassing SHOX or its enhancers have been identified in approximately 60% of LWD and approximately 15% of idiopathic short stature (ISS) individuals. Recently SHOX duplications have been described in LWD/ISS but also in individuals with other clinical manifestations, thus questioning their pathogenicity. OBJECTIVE: The objective of the study was to investigate the pathogenicity of SHOX duplications in LWD and ISS. DESIGN AND METHODS: Multiplex ligation-dependent probe amplification is routinely used in our unit to analyze for SHOX/pseudoautosomal region 1 copy number changes in LWD/ISS referrals. Quantitative PCR, microsatellite marker, and fluorescence in situ hybridization analysis were undertaken to confirm all identified duplications. RESULTS: During the routine analysis of 122 LWD and 613 ISS referrals, a total of four complete and 10 partial SHOX duplications or multiple copy number (n > 3) as well as one duplication of the SHOX 5' flanking region were identified in nine LWD and six ISS cases. Partial SHOX duplications appeared to have a more deleterious effect on skeletal dysplasia and height gain than complete SHOX duplications. Importantly, no increase in SHOX copy number was identified in 340 individuals with normal stature or 104 overgrowth referrals. CONCLUSION: MLPA analysis of SHOX/PAR1 led to the identification of partial and complete SHOX duplications or multiple copies associated with LWD or ISS, suggesting that they may represent an additional class of mutations implicated in the molecular etiology of these clinical entities.

Distribution and neurochemical characterization of protein kinase C-theta and -delta in the rodent hypothalamus.

PKC-theta (PKC-θ), a member of the novel protein kinase C family (nPKC), regulates a wide variety of functions in the periphery. However, its presence and role in the CNS has remained largely unknown. Recently, we demonstrated the presence of PKC-θ in the arcuate hypothalamic nucleus (ARC) and knockdown of PKC-θ from the ARC protected mice from developing diet-induced obesity. Another isoform of the nPKC group, PKC-delta (PKC-δ), is expressed in several non-hypothalamic brain sites including the thalamus and hippocampus. Although PKC-δ has been implicated in regulating hypothalamic glucose homeostasis, its distribution in the hypothalamus has not previously been described. In the current study, we used immunohistochemistry to examine the distribution of PKC-θ and -δ immunoreactivity in rat and mouse hypothalamus. We found PKC-θ immunoreactive neurons in several hypothalamic nuclei including the ARC, lateral hypothalamic area, perifornical area and tuberomammillary nucleus. PKC-δ immunoreactive neurons were found in the paraventricular and supraoptic nuclei. Double-label immunohistochemisty in mice expressing green fluorescent protein either with the long form of leptin receptor (LepR-b) or in orexin (ORX) neurons indicated that PKC-θ is highly colocalized in lateral hypothalamic ORX neurons but not in lateral hypothalamic LepR-b neurons. Double-label immunohistochemistry in oxytocin-enhanced yellow fluorescent protein mice or arginine vasopressin-enhanced green fluorescent protein (AVP-EGFP) transgenic rats revealed a high degree of colocalization of PKC-δ within paraventricular and supraoptic oxytocin neurons but not the vasopressinergic neurons. We conclude that PKC-θ and -δ are expressed in different hypothalamic neuronal populations.

Characterization of a familial balanced rec(13) in a child with mild MR and his half-sibling with two structurally rearranged chromosomes 13.

In this report, we describe a 7-year-old child with mild mental retardation, developmental delay, and learning disabilities. His karyotype contained a rearrangement of chromosome 13, which appeared to include a duplication of 13q31-qter and a deletion of 13p12-pter regions. The chromosomal origin of the additional material was confirmed by fluorescence in situ hybridization (FISH) using a whole chromosome painting probe specific for chromosome 13. Family studies showed that his mother carried a balanced inversion of chromosome 13 and that his half-brother carried the balanced pericentric inversion of chromosome 13 from his mother as well as another structural rearrangement involving chromosome 13 presumably from his father. The findings from this study suggested that the proband's abnormal 13 resulted from an unbalanced crossing-over between the normal and maternal inverted chromosome 13.

Most X;autosome translocations associated with premature ovarian failure do not interrupt X-linked genes.

Balanced translocations with breakpoints in a critical region of the X chromosome, Xq13-->q26, are associated with premature ovarian failure (POF). Translocations may cause POF either by affecting expression of specific X-linked genes essential for maintenance of normal ovarian function or by a chromosomal effect such as inhibition of meiotic pairing or altered X inactivation. We previously mapped seven Xq translocation breakpoints associated with POF to approximately 75-kb intervals. One translocation disrupted an aminopeptidase gene, XPNPEP2. We have now refined the map location of the remaining six breakpoints with respect to known genes and transcription units predicted from the draft human genome sequence. Only one of the six breakpoints disrupts a gene, DACH2, the human ortholog of a mouse gene expressed in embryonic nervous tissue, sensory organs, and limbs. DACH2 has no obvious relationship to ovarian function. The other five breakpoints fall in apparently intragenic regions. Our results are most consistent with models for POF associated with X;autosome translocations that involve generalized chromosome effects.

Persistent cognitive deficits in adult women with Turner syndrome.

BACKGROUND: Turner syndrome (TS) has a characteristic neurocognitive profile. Verbal abilities are, in general, normal; however, women with TS, as a group, have specific deficits in visual-spatial abilities, visual-perceptual abilities, motor function, nonverbal memory, executive function, and attentional abilities. Observed deficits could be caused by genetic or endocrine factors. OBJECTIVE: To evaluate the specific cognitive deficits that appear to persist in adulthood, are not estrogen-responsive, and may be genetically determined. METHODS: The cognitive performance of adult women with TS (n = 71) who were estrogen repleted was compared with verbal IQ- and socioeconomic status-matched female controls (n = 50). Sixty-one women with TS had ovarian failure and received estrogen replacement and 10 had preserved endogenous ovarian function and were not receiving estrogen replacement at the time of evaluation. RESULTS: Similar to children and adolescents with TS, adults with TS have normal verbal IQ but have relative difficulty on measures of spatial/perceptual skills, visual-motor integration, affect recognition, visual memory, attention, and executive function despite estrogen replacement. These deficits are apparent in women with TS despite apparently adequate estrogen effect, either endogenous or by hormone replacement. CONCLUSION: The cognitive phenotypes of adults with TS, with or without ovarian failure, are similar, indicating that estrogen replacement does not have a major impact on the cognitive deficits of adults with TS.

Phenotypes Associated with SHOX Deficiency.

Leri-Weill dyschondrosteosis (LWD) (MIM 127300) is a dominantly inherited skeletal dysplasia characterized phenotypically by Madelung wrist deformity, mesomelia, and short stature. LWD can now be defined genetically by haploinsufficiency of the SHOX (short stature homeobox-containing) gene. We have studied 21 LWD families (43 affected LWD subjects, including 32 females and 11 males, ages 3-56 yr) with confirmed SHOX abnormalities. We investigated the relationship between SHOX mutations, height deficit, and Madelung deformity to determine the contribution of SHOX haploinsufficiency to the LWD and Turner syndrome (TS) phenotypes. Also, we examined the effects of age, gender, and female puberty (estrogen) on the LWD phenotype. SHOX deletions were present in affected individuals from 17 families (81%), and point mutations were detected in 4 families (19%). In the LWD subjects, height deficits ranged from -4.6 to +0.6 SD (mean +/- SD = -2.2 +/- 1.0). There were no statistically significant effects of age, gender, pubertal status, or parental origin of SHOX mutations on height z-score. The height deficit in LWD is approximately two thirds that of TS. Madelung deformity was present in 74% of LWD children and adults and was more frequent and severe in females than males. The prevalence of the Madelung deformity was higher in the LWD vs. a TS population. The prevalence of increased carrying angle, high arched palate, and scoliosis was similar in the two populations. In conclusion, SHOX deletions or mutations accounted for all of our LWD cases. SHOX haploinsufficiency accounts for most, but not all, of the TS height deficit. The LWD phenotype shows some gender- and age-related differences.

A man who inherited his SRY gene and Leri-Weill dyschondrosteosis from his mother and neurofibromatosis type 1 from his father.

We report on a man with neurofibromatosis type 1 (NF1) and Leri-Weill dyschondrosteosis (LWD). His father had NF1. His mother had LWD plus additional findings of Turner syndrome (TS): high arched palate, bicuspid aortic valve, aortic stenosis, and premature ovarian failure. The proband's karyotype was 46,X,dic(X;Y)(p22.3;p11.32). Despite having almost the same genetic constitution as 47,XXY Klinefelter syndrome, he was normally virilized, although slight elevation of serum gonadotropins indicated gonadal dysfunction. His mother's karyotype was mosaic 45,X[17 cells]/46,X,dic(X;Y)(p22.3;p11.32)[3 cells].ish dic(X;Y)(DXZ1 +,DYZ1 + ). The dic(X;Y) chromosome was also positive for Y markers PABY, SRY, and DYZ5, but negative for SHOX. The dic(X;Y) chromosome was also positive for X markers DXZ1 and a sequence < 300 kb from PABX, suggesting that the deletion encompassed only pseudoautosomal sequences. Replication studies indicated that the normal X and the dic(X;Y) were randomly inactivated in the proband's lymphocytes. LWD in the proband and his mother was explained by SHOX haploinsufficiency. The mother's female phenotype was most likely due to 45,X mosaicism. This family segregating Mendelian and chromosomal disorders illustrates extreme sex chromosome variation compatible with normal male and female sexual differentiation. The case also highlights the importance of karyotyping for differentiating LWD and TS, especially in patients with findings such as premature ovarian failure or aortic abnormalities not associated with isolated SHOX haploinsufficiency.

Molecular analysis of genes on Xp controlling Turner syndrome and premature ovarian failure (POF).

Monosomy X has been known to be the chromosomal basis of Turner syndrome (TS) for more than four decades. A large body of cytogenetic data indicates that most TS features are due to reduced dosage of genes on the short arm of the X chromosome (Xp). Phenotype mapping studies using molecular cytogenetic and genetic techniques are beginning to localize the Xp genes that are important for various TS features, and a comprehensive catalog of candidate genes is becoming available through the Human Genome Project and related research. It is now possible to assess the contributions of individual genes to the TS phenotype by mutational analysis of karyotypically normal persons with specific TS features. This strategy has succeeded in identifying a gene involved in short stature and is being applied to premature ovarian failure and other TS phenotypes.

A 13-year-old boy with cognitive impairment, retinoblastoma, and Wilson disease.

A developmentally delayed child manifested retinoblastoma at age 4 years and Wilson disease at age 11, a previously unreported association. Cytogenetic and molecular analysis showed an interstitial deletion in the long arm of the paternally derived homologue of chromosome 13 (13q14.2-13q22.2), which encompasses the retinoblastoma and Wilson disease loci. The authors postulate that the co-occurrence of retinoblastoma and Wilson disease was the consequence of an acquired somatic mutation at the retinoblastoma locus and an inherited mutation at the Wilson disease locus of the maternally derived chromosome 13, superimposed on the hemizygosity associated with the paternally derived deletion.

A fork in the road to fertility.

Haploinsufficiency of FOXL2, a new forkhead transcription factor, causes blepharophimosis/ptosis/epicanthus inversus syndrome (BPES), a rare developmental disorder affecting the eyelid and sometimes the ovary. A new study implicates FOXL2 as the first human gene required for the maintenance of ovarian follicles. The discovery of FOXL2 may provide insight into the causes of idiopathic premature ovarian failure, a disease that burdens many infertile couples.

The X chromosome and the ovary.

X chromosome abnormalities are the leading identifiable cause of premature ovarian failure (POF). POF-related abnormalities range from the complete absence of one X chromosome to assorted deletions and translocations to mutations in specific genes. The diversity of X chromosome abnormalities associated with POF indicates that the disorder is genetically heterogeneous. Potential molecular mechanisms include both dominant and recessive mutations in X-linked genes as well as nonspecific chromosome effects that impair meiosis. A list of candidate X-linked POF genes is emerging from molecular studies of X chromosome abnormalities, data from the Human Genome Project and related functional genomics projects, and the results of gene targeting experiments in mice. Mutational analysis of candidate genes in a large number of women with idiopathic POF is needed to determine which of these genes contribute to the cause of this disorder.

Voice handicap index change following treatment of voice disorders.

Outcome measurements of voice disorders is an important new area for both the evaluation of voice-disordered patients and evaluation of treatment efficacy. The Voice Handicap Index (VHI) measures the patient's perception of the impact of his or her voice-disorder. The VHI was used in this study to measure the changes of the patient's perception following treatment for four different voice disorders. The VHI showed a significant change following treatment for unilateral vocal fold paralysis, vocal cyst/polyp, and muscle tension dysphonia. Results of this paper indicate that the VHI is a useful instrument to monitor the treatment efficacy for voice disorders.

The Turner syndrome-associated neurocognitive phenotype maps to distal Xp.

Turner syndrome (TS) is associated with a characteristic neurocognitive profile that includes impaired visuospatial/perceptual abilities. We used a molecular approach to identify a critical region of the X chromosome for neurocognitive aspects of TS. Partial deletions of Xp in 34 females were mapped by FISH or by loss of heterozygosity of polymorphic markers. Discriminant function analysis optimally identified the TS-associated neurocognitive phenotype. Only subjects missing approximately 10 Mb of distal Xp manifested the specified neurocognitive profile. The phenotype was seen with either paternally or maternally inherited deletions and with either complete or incomplete skewing of X inactivation. Fine mapping of informative deletions implicated a critical region of <2 Mb within the pseudoautosomal region (PAR1). We conclude that haploinsufficiency of PAR1 gene(s) is the basis for susceptibility to the TS neurocognitive phenotype.

Neurodevelopmental and psychosocial aspects of Turner syndrome.

Turner syndrome (TS) is the complex phenotype of human females with complete or partial absence of the second sex chromosome, or monosomy X. A characteristic neurocognitive and psychosocial profile has also been described in TS females. Typically, specific deficits in visual-spatial/perceptual abilities, nonverbal memory function, motor function, executive function, and attentional abilities occur in TS children and adults of varying races and socioeconomic status. TS-associated psychosocial difficulties occur in the areas of maturity and social skills. We hypothesize that a subset of the neurocognitive deficits (visual-spatial/perceptual abilities) are genetically determined and result from abnormal expression of one or more X chromosome genes. In addition, a different subset of these neurocognitive deficits (memory, reaction time, and speeded motor function) result from estrogen deficiency and are at least somewhat reversible with estrogen treatment. The TS-associated psychosocial problems are most likely linked to these core neurocognitive deficits and do not reflect a separate and independent component of the syndrome. Turner syndrome research has progressed significantly over the last decade. The field has moved from descriptive reports based on single individuals or small clinical samples to the use of experimental designs with larger, more diverse and representative samples. This degree of variability among individuals with Turner syndrome in all domains (karyotype or genetic constitution, physical attributes, neurocognitive and social functioning) suggests the need to identify risk and protective factors contributing to the heterogeneity in the phenotype. Active education about TS and participation in patient advocacy groups such as the Turner Syndrome Society of the United States (http://www. turner-syndrome-us.org/) has provided new information for TS adults and families as well as a supportive peer group. MRDD Research Reviews 2000;6:135-141.

Physical mapping of nine Xq translocation breakpoints and identification of XPNPEP2 as a premature ovarian failure candidate gene.

Women with balanced translocations between the long arm of the X chromosome (Xq) and an autosome frequently suffer premature ovarian failure (POF). Two "critical regions" for POF which extend from Xq13-->q22 and from Xq22-->q26 have been identified using cytogenetics. To gain insight into the mechanism(s) responsible for ovarian failure in women with X;autosome translocations, we have molecularly characterized the translocation breakpoints of nine X chromosomes. We mapped the breakpoints using somatic cell hybrids retaining the derivative autosome and densely spaced markers from the X-chromosome physical map. One of the POF-associated breakpoints in a critical region (Xq25) mapped to a sequenced PAC clone. The translocation disrupts XPNPEP2, which encodes an Xaa-Pro aminopeptidase that hydrolyzes N-terminal Xaa-Pro bonds. XPNPEP2 mRNA was detected in fibroblasts that carry the translocation, suggesting that this gene at least partially escapes X inactivation. Although the physiologic substrates for the enzyme are not known, XPNPEP2 is a candidate gene for POF. Our breakpoint mapping data will help to identify additional candidate POF genes and to delineate the Xq POF critical region(s).

Profound obesity associated with a balanced translocation that disrupts the SIM1 gene.

Studies of mice and humans have revealed a number of genes that when mutated result in severe obesity. We have studied a unique girl with early-onset obesity and a de novo balanced translocation between chromosomes 1p22.1 and 6q16.2. Her weight gain is most likely due to excessive food intake, since measured energy expenditure was normal. We cloned and sequenced both translocation breakpoints. The translocation does not appear to affect any transcription unit on 1p, but it disrupts the SIM1 gene on 6q. SIM1 encodes a human homolog of Drosophila Sim (Single-minded), a transcription factor involved in midline neurogenesis, and is a prototypical member of the bHLH-PAS (basic helix-loop-helix + period, aryl hydrocarbon receptor, Single-minded) gene family. Our subject's trans- location separates the 5' promoter region and bHLH domain from the 3' PAS and putative transcriptional regulation domains. The transcriptional targets of SIM1 are not known. Mouse Sim1 is expressed in the developing kidney and central nervous system, and is essential for formation of the supraoptic and paraventricular (PVN) nuclei of the hypothalamus. Previous neuroanatomical and pharmacological studies have implicated the PVN in the regulation of body weight: PVN neurons express the melanocortin 4 receptor and appear to be physiological targets of alpha-melanocyte-stimulating hormone, which inhibits food intake. We hypothesize that haploinsufficiency of SIM1, possibly acting upstream or downstream of the melanocortin 4 receptor in the PVN, is responsible for severe obesity in our subject.