Systemic Inflammation and Normocytic Anemia in DOCK11 Deficiency.

BACKGROUND: Increasing evidence links genetic defects affecting actin-regulatory proteins to diseases with severe autoimmunity and autoinflammation, yet the underlying molecular mechanisms are poorly understood. Dedicator of cytokinesis 11 (DOCK11) activates the small Rho guanosine triphosphatase (GTPase) cell division cycle 42 (CDC42), a central regulator of actin cytoskeleton dynamics. The role of DOCK11 in human immune-cell function and disease remains unknown. METHODS: We conducted genetic, immunologic, and molecular assays in four patients from four unrelated families who presented with infections, early-onset severe immune dysregulation, normocytic anemia of variable severity associated with anisopoikilocytosis, and developmental delay. Functional assays were performed in patient-derived cells, as well as in mouse and zebrafish models. RESULTS: We identified rare, X-linked germline mutations in DOCK11 in the patients, leading to a loss of protein expression in two patients and impaired CDC42 activation in all four patients. Patient-derived T cells did not form filopodia and showed abnormal migration. In addition, the patient-derived T cells, as well as the T cells from Dock11-knockout mice, showed overt activation and production of proinflammatory cytokines that were associated with an increased degree of nuclear translocation of nuclear factor of activated T cell 1 (NFATc1). Anemia and aberrant erythrocyte morphologic features were recapitulated in a newly generated dock11-knockout zebrafish model, and anemia was amenable to rescue on ectopic expression of constitutively active CDC42. CONCLUSIONS: Germline hemizygous loss-of-function mutations affecting the actin regulator DOCK11 were shown to cause a previously unknown inborn error of hematopoiesis and immunity characterized by severe immune dysregulation and systemic inflammation, recurrent infections, and anemia. (Funded by the European Research Council and others.).

Pediatric Reference Centiles of Bone Mineral Density and Body Composition of Lower Limbs.

Localized neurological diseases such as spina bifida are often accompanied by normal upper limb and spinal bone mineral density (BMD), whereas regional BMD of the lower limbs may be decreased. Therefore, regional BMD measurements may be more accurate to quantify regional bone health. Until now, no pediatric reference centiles of bone mineral density and body composition of the lower extremities are available for Hologic DXA systems. The objective was to generate age-and sex specific reference centiles of DXA scans of lower limbs for Hologic DXA systems. Data from the National Health and Nutrition Examination Survey of the period 1999-2004 (age 8 - 20 years) were used to generate age-specific and sex-specific reference centiles for the non-Hispanic Black, non-Hispanic White and Mexican-American NHANES study population. The LMS method was used to calculate the reference centiles. Data of DXA scans of 2233 non-Hispanic black children (880 females), 1869 non-Hispanic white children (803 females) and 2350 Mexican American children (925 females) were used to create age-specific and sex-specific reference curves. We presented age-and sex-specific reference centiles for regional bone mineral density, bone mineral content, lean body mass and fat mass at the lower limbs for children and adolescents which were ethnicity specific and directly applicable to Hologic QDR-4500A fan-beam densitometer.

Diagnostic Evaluation of the Functional Muscle-Bone Unit in Children With Cerebral Palsy With and Without Low Trauma Fractures.

Children and adolescents with cerebral palsy (CP) are at increased risk of low trauma fractures (LTF) due to low bone mineral content (BMC). The risk of LTFs might be overestimated by only age - and sex adjusted Z-scores for BMC because Z-score based DXA techniques do not take into account other relevant parameters like height, muscle and fat mass. This study aimed to present an update of the functional muscle-bone unit-algorithm (uFMBU-A) to evaluate bone health in children with CP in order to predict the risk of LTF taking into account the parameters sex, age, height, muscle and fat mass. We performed a monocentric retrospective analysis of 177 DXA-scans of children and adolescents with CP aged 8-19. Six of these 177 patients had sustained at least 1 LTF. Age-, sex- and size adjusted Z-scores of total body less head (TBLH)-BMC, lean body mass and fat mass were calculated. The uFMBU-A was applied to the study group and results were compared with established Z-score based DXA-measurements and algorithm based diagnostic techniques concerning the prediction of LTF risk. The uFMBU-A had the greatest diagnostic odds ratio (13.3 [95% CI 2.41; 72.9]) of the evaluated predictors with a sensitivity of 50.0% (95% CI 11.8; 88.2), specifity of 93% (95% CI 88.1; 96.3). The uFMBU-A was the most accurate method of the evaluated parameters to predict LTF in children with CP and is recommended when evaluating bone health.

Correction: A new microdeletion syndrome involving TBC1D24, ATP6V0C, and PDPK1 causes epilepsy, microcephaly, and developmental delay.

The original version of this Article contained an error in the spelling of the author Siddharth Banka, which was incorrectly given as Siddhart Banka. This has now been corrected in both the PDF and HTML versions of the Article.

A new microdeletion syndrome involving TBC1D24, ATP6V0C, and PDPK1 causes epilepsy, microcephaly, and developmental delay.

PURPOSE: Contiguous gene deletions are known to cause several neurodevelopmental syndromes, many of which are caused by recurrent events on chromosome 16. However, chromosomal microarray studies (CMA) still yield copy-number variants (CNVs) of unknown clinical significance. We sought to characterize eight individuals with overlapping 205-kb to 504-kb 16p13.3 microdeletions that are distinct from previously published deletion syndromes. METHODS: Clinical information on the patients and bioinformatic scores for the deleted genes were analyzed. RESULTS: All individuals in our cohort displayed developmental delay, intellectual disability, and various forms of seizures. Six individuals were microcephalic and two had strabismus. The deletion was absent in all 13 parents who were available for testing. The area of overlap encompasses seven genes including TBC1D24, ATP6V0C, and PDPK1 (also known as PDK1). Bi-allelic TBC1D24 pathogenic variants are known to cause nonsyndromic deafness, epileptic disorders, or DOORS syndrome (deafness, onychodystrophy, osteodystrophy, mental retardation, seizures). Sanger sequencing of the nondeleted TBC1D24 allele did not yield any additional pathogenic variants. CONCLUSIONS: We propose that 16p13.3 microdeletions resulting in simultaneous haploinsufficiencies of TBC1D24, ATP6V0C, and PDPK1 cause a novel rare contiguous gene deletion syndrome of microcephaly, developmental delay, intellectual disability, and epilepsy.

A novel mutation in PIGW causes glycosylphosphatidylinositol deficiency without hyperphosphatasia.

In recent years, many mutations have been identified that affect the biosynthesis of the glycosylphosphatidylinositol anchor, a biomolecule that attaches surface molecules to cell membranes. Here, we present two second-degree cousins with unexplained patterns of seizures. Next-generation sequencing identified the homozygous c.460A>G; p.(R154G) PIGW mutation in both patients. Transfection of the mutated allele into Pigw-defective CHO cells indicated impaired enzymatic activity of the mutated PIGW product. Alkaline phosphatase did not exceed the upper normal range and flow cytometry of CD16, CD24, and CD66c on granulocytes showed subtle changes of the cellular expression of the glycosylphosphatidylinositol-anchored proteins. The patients' phenotype is therefore remarkably different from the phenotype of the only other described individual with PIGW mutations. Patients might therefore be missed when relying on traditional flow cytometry of glycosylphosphatidylinositol-anchored proteins only and we suggest that glycosylphosphatidylinositol-deficiency should be considered even with patients not showing the typical clinical phenotypes. © 2016 Wiley Periodicals, Inc.

Natural History and Developmental Trajectories of Individuals With Disease-Causing Variants in STXBP1.

BACKGROUND AND OBJECTIVES: Pathogenic variants in STXBP1 are among the major genetic causes of neurodevelopmental disorders. Despite the increasing number of individuals diagnosed without a history of epilepsy, little is known about the natural history and developmental trajectories in this subgroup and endpoints for future therapeutic studies are limited to seizure control. METHODS: We performed a cross-sectional retrospective study using standardized questionnaires for clinicians and caregivers of individuals with STXBP1-related disorders capturing medical histories, genetic findings, and developmental outcomes. Motor and language function were assessed using Gross Motor Function Classification System (GMFCS) scores and a speech impairment score and were compared within and across clinically defined subgroups. RESULTS: We collected data of 71 individuals with STXBP1-related disorders, including 44 previously unreported individuals. Median age at inclusion was 5.3 years (interquartile range 3.5-9.3) with the oldest individual aged 43.8 years. Epilepsy was absent in 18/71 (25%) of individuals. The range of developmental outcomes was broad, including 2 individuals presenting with close to age-appropriate motor development. Twenty-nine of 61 individuals (48%) were able to walk unassisted, and 24/69 (35%) were able to speak single words. Individuals without epilepsy presented with a similar onset and spectrum of phenotypic features but had lower GMFCS scores (median 3 vs 4, p < 0.01) than individuals with epilepsy. Individuals with epileptic spasms were less likely to walk unassisted than individuals with other seizure types (6% vs 58%, p < 0.01). Individuals with early epilepsy onset had higher speech impairment scores (p = 0.02) than individuals with later epilepsy onset. DISCUSSION: We expand the spectrum of STXBP1-related disorders and provide clinical features and developmental trajectories in individuals with and without a history of epilepsy. Individuals with epilepsy, in particular epileptic spasms, and neonatal or early-onset presented with less favorable motor and language functional outcomes compared with individuals without epilepsy. These findings identify children at risk for severe disease and can serve as comparator for future interventional studies in STXBP1-related disorders.

Interaction between fat- and muscle development in children and adolescents.

Background: Prevalence of obesity increased noticeably during the last decades. Little is known so far about the association between fat accumulation due to obesity and skeletal muscle mass. The aim of this study was to describe the association between fat mass and muscle mass after adjusting for relevant confounding factors in the National Health and Nutrition Examination Survey (NHANES) study population of children and adolescents. We postulated a negative correlation between fat mass and lean body mass. Methodology: A total of 849 whole body DXA-scans of the NHANES study population of children and adolescents aged eight to twenty years of the years 1999-2004 were eligible for statistical analysis. Appendicular lean body mass (appLBM) was used to evaluate muscle mass. Bivariate analysis (Pearson's correlation coefficient), multiple linear regression analysis and mediation analysis were performed. The multiple regression analysis and mediation analysis were adjusted for weight, age height, sex ethnicity and physical activity. Results: Fat mass correlates with appendicular lean body mass (Pearons's r 0.336, p < 0.001). In the multiple linear regression analysis the regression coefficient between appLBM and FM was positive (0.204; p < 0.001), when considering appendicular lean body mass, fat mass and body weight, the regression coefficient was negative (-0.517; p < 0.001). Conclusions: Study results indicate a negative association of fat mass and skeletal muscle mass in children and adolescents, when weight, age, height, sex ethnicity and physical activity are considered. Further investigations are needed to evaluate if there is a biochemical interaction between fat cells and muscle cells that could explain this effect.

Sequential acquisition of IgH and TCR rearrangements during the preleukemic phase of acute lymphoblastic leukemia in an adolescent patient.

Acute lymphoblastic leukemia (ALL) can be preceded by a prodromal phase of bone marrow failure. In serial trephine biopsies in a girl with acquired bone marrow hypoplasia, we have identified a monoclonal B-cell precursor population characterized by a clone-specific IgH-FR3 gene rearrangement. Progression to ALL more than 4 months later was accompanied by acquisition of an additional T-cell receptor rearrangement. Thus, hypoplastic pre- and overt leukemia share a common clonal origin. Prospective biobanking and extended molecular analysis can help to better understand the nature and sequence of genetic events during progression of a covert (pre)leukemic clone.

Molecular diagnosis of Shwachman-Diamond syndrome in a child with incomplete clinical disease phenotype.

We report a 6-year-old female with congenital bone marrow failure, who was referred for allogeneic stem cell transplantation. An initial work-up in infancy had not revealed any consistent symptoms associated with an inherited syndrome. Computed tomography of her abdomen for gastrointestinal bleeding after transplantation incidentally revealed a fat-replaced pancreas and led to the molecular diagnosis of Shwachman-Diamond syndrome (SDS) in the absence of clinical exocrine pancreatic insufficiency. We conclude that SDS may escape the clinical consensus criteria for the disease. Increased awareness of unusual presentations may allow confirming the suspected diagnosis by molecular analysis and ensure optimal management.

UICC-2002 TNM classification is not suitable for differentiated thyroid cancer in children and adolescents.

BACKGROUND: Recently the UICC-TNM classification for differentiated thyroid cancer (DTC) was changed neglecting the special circumstances for children affected by the disease. While the 1997 TNM classification grouped tumours

Number of genomic imbalances correlates with the overall survival for adrenocortical cancer in childhood.

BACKGROUND: Adrenocortical tumours (ACT) in children are rare and, if malignant, often associated with poor prognosis. Relevant cytogenetic factors for prognosis are hardly available. PROCEDURES: We analysed 14 adrenocortical cancers (ACC) of children by comparative genomic hybridisation (CGH). RESULTS: The total number of genomic imbalances ranged from 1 to 17 in individual tumour samples. The most common imbalances were +1q (57%), +12p (50%), +12q (50%), +1p (43%), +7q (42%), +9q (42%), +15q (42%), and -4q (57%), -11q (57%), -4p (42%), and -16q (42%). The median number of genomic changes was 5.5 (n = 8) in pT1-pT2 and 15.5 (n = 6) in pT3-pT4 tumours. The median number was 4 in the eight patients, who remain in remission more than 51 months and 15.5 in the six patients, who have died from the disease within 44 months. Moreover, all seven patients with less than 10 individual imbalances were in remission (median follow-up 72 months), while all but one patient with 10 and more individual imbalances (n = 7) have died from the disease (median survival time 30 months). Comparison of the data from children and adults revealed characteristic differences. Gain of 1p and loss of 4p, 4q and 16q are frequent in childhood and rare in adults. Inversely, loss of 1p is rare in childhood but frequent in adult ACT. CONCLUSION: The number of CGH imbalances appeared to have a predictive value for overall survival in paediatric ACC.

The antimycotic ciclopirox olamine induces HIF-1alpha stability, VEGF expression, and angiogenesis.

The heterodimeric hypoxia-inducible factor (HIF)-1 is a master regulator of oxygen homeostasis. Protein stability and transactivation function of the alpha subunit are controlled by iron- and oxygen-dependent hydroxylation of proline and asparagine residues. The anti-mycotic ciclopirox olamine (CPX) is a lipophilic bidentate iron chelator that stabilizes HIF-1alpha under normoxic conditions at lower concentrations than other iron chelators, probably by inhibiting HIF-1alpha hydroxylation. As shown by the inhibition of iron-dependent quenching of FITC-labeled deferoxamine (DFX) fluorescence, CPX appears to have an even higher affinity for iron than DFX. Initial observations that treatment with 1% CPX, but not with placebo, occasionally caused reddening of wound margins in a mouse skin wound model prompted us to investigate the capability of CPX to induce angiogenesis. CPX-induced HIF-1-mediated reporter gene activity and endogenous HIF-1 target gene expression, including elevation of transcription, mRNA, and protein levels of the vascular endothelial growth factor (VEGF). In the chick chorioallantoic membrane assay, inert polymer disks containing CPX but not the solvent alone induced angiogenesis. In summary, these results suggest that CPX induces angiogenesis in vivo via HIF-1 and VEGF induction. Therefore, CPX might serve as an alternative to recombinant VEGF treatment or to VEGF gene therapy for therapeutic angiogenesis.

Delineation of PIGV mutation spectrum and associated phenotypes in hyperphosphatasia with mental retardation syndrome.

Three different genes of the glycosylphosphatidylinositol anchor synthesis pathway, PIGV, PIGO, and PGAP2, have recently been implicated in hyperphosphatasia-mental retardation syndrome (HPMRS), also known as Mabry syndrome, a rare autosomal recessive form of intellectual disability. The aim of this study was to delineate the PIGV mutation spectrum as well as the associated phenotypic spectrum in a cohort of 16 individuals diagnosed with HPMRS on the basis of intellectual disability and elevated serum alkaline phosphate as minimal diagnostic criteria. All PIGV exons and intronic boundaries were sequenced in 16 individuals. Biallelic PIGV mutations were identified in 8 of 16 unrelated families with HPMRS. The most frequent mutation detected in about 80% of affected families including the cases reported here is the c.1022C>A PIGV mutation, which was found in both the homozygous as well as the heterozygous state. Four further mutations found in this study (c. 176T>G, c.53G>A, c.905T>C, and c.1405C>T) are novel. Our findings in the largest reported cohort to date significantly extend the range of reported manifestations associated with PIGV mutations and demonstrate that the severe end of the clinical spectrum presents as a multiple congenital malformation syndrome with a high frequency of Hirschsprung disease, vesicoureteral, and renal anomalies as well as anorectal malformations. PIGV mutations are the major cause of HPMRS, which displays a broad clinical variability regarding associated malformations and growth patterns. Severe developmental delays, particular facial anomalies, brachytelephalangy, and hyperphosphatasia are consistently found in PIGV-positive individuals.

Copper-dependent activation of hypoxia-inducible factor (HIF)-1: implications for ceruloplasmin regulation.

Cellular oxygen partial pressure is sensed by a family of prolyl-4-hydroxylase domain (PHD) enzymes that modify hypoxia-inducible factor (HIF)alpha subunits. Upon hydroxylation under normoxic conditions, HIFalpha is bound by the von Hippel-Lindau tumor suppressor protein and targeted for proteasomal destruction. Since PHD activity is dependent on oxygen and ferrous iron, HIF-1 mediates not only oxygen- but also iron-regulated transcriptional gene expression. Here we show that copper (CuCl(2)) stabilizes nuclear HIF-1alpha under normoxic conditions, resulting in hypoxia-response element (HRE)-dependent reporter gene expression. In in vitro hydroxylation assays CuCl(2) inhibited prolyl-4-hydroxylation independently of the iron concentration. Ceruloplasmin, the main copper transport protein in the plasma and a known HIF-1 target in vitro, was also induced in vivo in the liver of hypoxic mice. Both hypoxia and CuCl(2) increased ceruloplasmin (as well as vascular endothelial growth factor [VEGF] and glucose transporter 1 [Glut-1]) mRNA levels in hepatoma cells, which was due to transcriptional induction of the ceruloplasmin gene (CP) promoter. In conclusion, our data suggest that PHD/HIF/HRE-dependent gene regulation can serve as a sensory system not only for oxygen and iron but also for copper metabolism, regulating the oxygen-, iron- and copper-binding transport proteins hemoglobin, transferrin, and ceruloplasmin, respectively.