Leukopenia, macrocytosis, and thrombocytopenia occur in young adults with Down syndrome.

Down syndrome (DS) is a common congenital disorder caused by trisomy 21. Due to the increase in maternal age with population aging and advances in medical treatment for fatal complications in their early childhood, the prevalence and life expectancy of DS individuals have greatly increased. Despite this rise in the number of DS adults, their hematological status remains poorly examined. Here, we report that three hematological abnormalities, leukopenia, macrocytosis, and thrombocytopenia, develop as adult DS-associated features. Multi- and uni-variate analyses on hematological data collected from 51 DS and 60 control adults demonstrated that young adults with DS are at significantly higher risk of (i) myeloid-dominant leukopenia, (ii) macrocytosis characterized by high mean cell volume (MCV) of erythrocytes, and (iii) lower platelet counts than the control. Notably, these features were more pronounced with age. Further analyses on DS adults would provide a deeper understanding and novel research perspectives for multiple aging-related disorders in the general population.

Brothers with novel compound heterozygous mutations in COL27A1 causing dental and genital abnormalities.

COL27A1 encodes a collagen type XXVII alpha 1 chain. It is the product of this gene that provides the structural support of connective tissue and is reported to be the causative gene of Steel syndrome (OMIM #615155). The primary symptoms of patients with this defect are consistent with systemic bone disease; however, recent reports note findings of intellectual disability and hearing loss. In this study, we identified novel COL27A1 compound heterozygous variants in two brothers with rhizomelia and congenital hip dislocation as well as dental and genital abnormalities that have not yet been reported in Steel syndrome. This variant, of maternal origin, caused an amino acid substitution of arginine for glycine, c.2026G>C or p.G676R, in the collagen helix domain, which is assumed to damage the structure of the helix. The paternally transmitted variant, c.2367G>A, is located at the 3' end of exon 12, and cDNA analysis revealed a splicing alteration. These novel, compound heterozygous COL27A1 variants might indicate an association of the gene with tooth and genital abnormalities.

Evaluation of Face2Gene using facial images of patients with congenital dysmorphic syndromes recruited in Japan.

An increasing number of genetic syndromes present a challenge to clinical geneticists. A deep learning-based diagnosis assistance system, Face2Gene, utilizes the aggregation of "gestalt," comprising data summarizing features of patients' facial images, to suggest candidate syndromes. Because Face2Gene's results may be affected by ethnicity and age at which training facial images were taken, the system performance for patients in Japan is still unclear. Here, we present an evaluation of Face2Gene using the following two patient groups recruited in Japan: Group 1 consisting of 74 patients with 47 congenital dysmorphic syndromes, and Group 2 consisting of 34 patients with Down syndrome. In Group 1, facial recognition failed for 4 of 74 patients, while 13-21 of 70 patients had a diagnosis for which Face2Gene had not been trained. Omitting these 21 patients, for 85.7% (42/49) of the remainder, the correct syndrome was identified within the top 10 suggested list. In Group 2, for the youngest facial images taken for each of the 34 patients, Down syndrome was successfully identified as the highest-ranking condition using images taken from newborns to those aged 25 years. For the oldest facial images taken at ≥20 years in each of 17 applicable patients, Down syndrome was successfully identified as the highest- and second-highest-ranking condition in 82.2% (14/17) and 100% (17/17) of the patients using images taken from 20 to 40 years. These results suggest that Face2Gene in its current format is already useful in suggesting candidate syndromes to clinical geneticists, using patients with congenital dysmorphic syndromes in Japan.

Pathogenetic basis of Takenouchi-Kosaki syndrome: Electron microscopy study using platelets in patients and functional studies in a Caenorhabditis elegans model.

The combined phenotype of thrombocytopenia accompanied by intellectual disability in patients with a de novo heterozygous mutation, i.e., p.Tyr64Cys in CDC42, signifies a clinically recognizable novel syndrome that has been eponymized as "Takenouchi-Kosaki syndrome" (OMIM #616737). In the present study, a detailed phenotypic analysis performed for a total of five patients with Takenouchi-Kosaki syndrome revealed that intellectual disability, macrothrombocytopenia, camptodactyly, structural brain abnormalities with sensorineural deafness, hypothyroidism, and frequent infections comprise the cardinal features of this condition. A morphologic analysis of platelets derived from three affected individuals was performed using electron microscopy. The platelets of the three patients were large and spherical in shape. Furthermore, platelet α-granules were decreased, while vacuoles were increased. We further performed a functional analysis of p.Tyr64Cys in CDC42 through CRISPR/Cas9-mediated gene editing in a Caenorhabditis elegans model. This functional analysis suggested that the mutant allele has hypomorphic effects. Takenouchi-Kosaki syndrome is clinically recognizable by the combined phenotype of intellectual disability, macrothrombocytopenia, camptodactyly, structural brain abnormalities with sensorineural deafness, hypothyroidism, and frequent infections as well as the identification of a heterozygous de novo mutation in CDC42, i.e., p.Tyr64Cys.

Double non-contiguous fractures in a patient with spondylo-epiphyseal dysplasia with spinal ankylosis treated with open and percutaneous spinal fixation technique: a case report.

BACKGROUND: Patients with ankylosing spines are susceptible to developing spinal fractures even with minor trauma and can develop early or late neurological injuries. These fractures require early and aggressive surgical management to enable spinal stability and/or neural decompression. Being highly unstable by nature, they require relatively long segment instrumentation and fusion, which can increase paravertebral soft tissue damage and perioperative bleeding. The purpose of this report is to describe a rare case of traumatic double fractures at the cervico-thoracic and thoraco-lumbar transition zones in ankylosing spine with spondylo-epiphyseal dysplasia (SED) of unknown cause, which were successfully treated with a combined open and percutaneous spinal fusion procedure. CASE PRESENTATION: A 46-year-old woman who was diagnosed with non-contiguous fractures in cervico-thoracic and thoraco-lumbar junction zones among multiple injuries sustained in a traffic accident was treated with hybrid techniques for posterior instrumentation with an open approach using a computed tomography (CT)-based navigation system and percutaneous pedicle-screwing method. She regained mobility to pre-admission levels and started walking on crutches 3 months postoperatively. Genetic testing for the cause of SED revealed no mutation in the COL2A1 or TRPVR4 genes. The union of fractured spine was confirmed on CT scan 1 year postoperatively. CONCLUSION: This is the first report of double spinal fractures in an ankylosing spine with genetically undetermined spondyloepiphyseal dysplasia. A long-segment posterior instrumentation procedure incorporating the invasive treatment of spinal fractures in ankylosing spondylitis or diffuse idiopathic hyperostosis was effective.

A hot-spot mutation in CDC42 (p.Tyr64Cys) and novel phenotypes in the third patient with Takenouchi-Kosaki syndrome.

Takenouchi-Kosaki syndrome (TKS) is a congenital malformation syndrome characterized by severe developmental delay, macrothrombocytopenia, camptodactyly, sensorineural hearing loss, and dysmorphic facial features. Recently, a heterozygous de novo mutation (p.Tyr64Cys) in the CDC42 gene, which encodes a key small GTP-binding protein of the Rho-subfamily, was identified in two unrelated patients with TKS. We herein report a third patient with TKS who had the same heterozygous CDC42 mutation. The phenotype of the patient was very similar to those of the two previously reported patients with TKS; however, she also demonstrated novel clinical manifestations, such as congenital hypothyroidism and immunological disturbance. Thus, despite the heterozygous mutation of CDC42 (p.Tyr64Cys) likely being a hot-spot mutation for TKS, its phenotype may be variable. Further studies and the accumulation of patients with CDC42 mutations are needed to clarify the phenotype in patients with TKS and the pathophysiological roles of the CDC42 mutation.

Maternally derived 15q11.2-q13.1 duplication and H19-DMR hypomethylation in a patient with Silver-Russell syndrome.

Silver-Russell syndrome (SRS) is a congenital developmental disorder characterized by intrauterine and postnatal growth failure, craniofacial features (including a triangular shaped face and broad forehead), relative macrocephaly, protruding forehead, body asymmetry and feeding difficulties. Hypomethylation of the H19 differentially methylated region (DMR) on chromosome 11p15.5 is the most common cause of the SRS phenotype. We report the first SRS patient with hypomethylation of the H19-DMR and maternally derived 15q11.2-q13.1 duplication. Although her clinical manifestations overlapped with those of previously reported SRS cases, the patient's intellectual disability and facial dysmorphic features were inconsistent with the SRS phenotype. Methylation analyses, array comparative genomic hybridization, and a FISH analysis revealed the hypomethylation of the H19-DMR and a maternally derived interstitial 5.7 Mb duplication at 15q11.2-q13.1 encompassing the Prader-Willi/Angelman critical region in the patient. On the basis of the genetic and clinical findings in the present and previously reported cases, it is unlikely that the 15q duplication in the patient led to the development of hypomethylation of the H19-DMR and it is reasonable to consider that the characteristic phenotype in the patient was caused by the coexistence of the two (epi)genetic conditions. Further studies are needed to clarify the mechanisms leading to methylation aberrations in SRS.

Three brothers with a nonsense mutation in KAT6A caused by parental germline mosaicism.

Mutations in KAT6A, encoding a member of the MYST family of histone acetyl-transferases, were recently reported in patients with a neurodevelopmental disorder (OMIM: #616268, autosomal dominant mental retardation-32). In this report, we describe three siblings with intellectual disability (ID) or global developmental delay and a KAT6A heterozygous nonsense mutation, i.e., c.3070C>T (p.R1024*, ENST00000406337; chr8:41795056G>A on hg19). This mutation was identified by whole-exome sequencing of all three siblings but not in a healthy sibling. The mutation was not detected in the peripheral blood of their parents, suggesting the existence of parental germline mosaicism. The primary symptoms of our patients included severe to profound ID or global developmental delay, including speech delay with craniofacial dysmorphism; these symptoms are consistent with symptoms previously described for patients with KAT6A mutations. Although several features are common among patients with KAT6A mutations, the features are relatively nonspecific, making it difficult to establish a clinical entity based on clinical findings alone. To the best of our knowledge, this is the first report of cases with a KAT6A mutation in an Asian population and these cases represent the first reported instances of germline mosaicism of this disease.

Detailed analysis of 26 cases of 1q partial duplication/triplication syndrome.

Partial 1q trisomy syndrome is a rare disorder. Because unbalanced chromosomal translocations often occur with 1q trisomy, it is difficult to determine whether patient symptoms are related to 1q trisomy or other chromosomal abnormalities. The present study evaluated genotype-phenotype correlations of 26 cases diagnosed with 1q partial trisomy syndrome. DNA microarray was used to investigate the duplication/triplication region of 16 cases. Although there was no overlapping region common to all 26 cases, the 1q41-qter region was frequently involved. One case diagnosed as a pure interstitial trisomy of chromosome 1q by G-banded karyotype analysis was instead found to be a pure partial tetrasomy by CytoScan HD Array. In four 1q trisomy syndrome cases involving translocation, the translocated partner chromosome could not be detected by DNA microarray analyzes despite G-banded karyotype analysis, because there were a limited number of probes available for the partner region. DNA microarray and G-banded karyotyping techniques were therefore shown to be compensatory diagnostic tools that should be used by clinicians who suspect chromosomal abnormalities. It is important to continue recruiting affected patients and observe and monitor their symptoms to reveal genotype-phenotype correlations and to fully understand their prognosis and identify causal regions of symptoms.

Effects of donepezil and serotonin reuptake inhibitor on acute regression during adolescence in Down syndrome.

A 14-year-old boy with Down syndrome (DS) showed a gradual decline in his daily activities and feeding capacities, and a marked deterioration triggered by a streptococcal infection was observed at the age of 15 years. He became bedridden, accompanied by sleep disturbance, sustained upward gaze, and generalized rigidity. Magnetic resonance imaging showed unremarkable findings, but antiglutamate receptor autoantibodies were positive in his cerebrospinal fluid. Treatment with thiamine infusion and steroid pulse therapy showed little effect, but gross motor dysfunction and appetite loss were ameliorated by the administration of l-DOPA and serotonin reuptake inhibitors. Thereafter, autistic behaviors predominated, including loss of social interaction, oral tendency, water phobia, and aggressiveness. Initiation of donepezil, an acetylcholinesterase inhibitor, resulted in the disappearance of these symptoms and total recovery of the patient to his previous psychosocial levels. We hypothesize that the acute regression in adolescence represents a process closely related to the defects of serotonergic and cholinergic systems that are innate to DS brains and not just a nonspecific comorbidity of depression or limbic encephalitis.

Neonatal case of novel KMT2D mutation in Kabuki syndrome with severe hypoglycemia.

A newborn Japanese girl with Kabuki syndrome had neonatal persistent hyperinsulinemic hypoglycemia, which seemed to be a rare complication of Kabuki syndrome. On sequence analysis she was found to have a novel heterozygous KMT2D mutation. Diazoxide therapy was effective for the hypoglycemia. Hypoglycemia should be considered when Kabuki syndrome patients have convulsion or other non-specific symptoms. Diazoxide may help to improve hypoglycemia in patients with Kabuki syndrome complicated with hyperinsulinemic hypoglycemia.

Heterozygous mutations in cyclic AMP phosphodiesterase-4D (PDE4D) and protein kinase A (PKA) provide new insights into the molecular pathology of acrodysostosis.

Acrodysostosis without hormone resistance is a rare skeletal disorder characterized by brachydactyly, nasal hypoplasia, mental retardation and occasionally developmental delay. Recently, loss-of-function mutations in the gene encoding cAMP-hydrolyzing phosphodiesterase-4D (PDE4D) have been reported to cause this rare condition but the pathomechanism has not been fully elucidated. To understand the pathogenetic mechanism of PDE4D mutations, we conducted 3D modeling studies to predict changes in the binding efficacy of cAMP to the catalytic pocket in PDE4D mutants. Our results indicated diminished enzyme activity in the two mutants we analyzed (Gly673Asp and Ile678Thr; based on PDE4D4 residue numbering). Ectopic expression of PDE4D mutants in HEK293 cells demonstrated this reduction in activity, which was identified by increased cAMP levels. However, the cells from an acrodysostosis patient showed low cAMP accumulation, which resulted in a decrease in the phosphorylated cAMP Response Element-Binding Protein (pCREB)/CREB ratio. The reason for this discrepancy was due to a compensatory increase in expression levels of PDE4A and PDE4B isoforms, which accounted for the paradoxical decrease in cAMP levels in the patient cells expressing mutant isoforms with a lowered PDE4D activity. Skeletal radiographs of 10-week-old knockout (KO) rats showed that the distal part of the forelimb was shorter than in wild-type (WT) rats and that all the metacarpals and phalanges were also shorter in KO, as the name acrodysostosis implies. Like the G-protein α-stimulatory subunit and PRKAR1A, PDE4D critically regulates the cAMP signal transduction pathway and influences bone formation in a way that activity-compromising PDE4D mutations can result in skeletal dysplasia. We propose that specific inhibitory PDE4D mutations can lead to the molecular pathology of acrodysostosis without hormone resistance but that the pathological phenotype may well be dependent on an over-compensatory induction of other PDE4 isoforms that can be expected to be targeted to different signaling complexes and exert distinct effects on compartmentalized cAMP signaling.

Assessment of lower urinary tract function in children with Down syndrome.

BACKGROUND: Despite the fact that functional lower urinary tract symptoms are common among people with Down syndrome (DS), their voiding function has not been studied precisely. Our goal was to assess the lower urinary tract functions in DS. METHODS: Fifty-five DS children aged 5-15 years old and 35 age-matched control children were evaluated by ultrasonography and uroflowmetry. RESULTS: Eleven (20%) DS children had no uresiesthesia, 21 (38%) were urinated under guidance, nine (16%) urinated fewer than three times a day, two (4%) urinated more than 10 times a day, three (5%) used diapers, and 26 (47%) had urinary incontinence. Seven (13%), 15 (27%), and 10 (18%) DS children had weak, prolonged and intermittent urination, respectively, and seven (13%) had urination with straining. In contrast, none of the control subjects had urinary problems. In the uroflowmetrical analysis, 10 (18%), 20 (37%), 11 (20%) and five (9%) DS children showed "bell-shaped," "plateau," "staccato" and "interrupted" patterns, respectively; the remaining nine (16%) could not be analyzed. In contrast, 21 (60%), one (3%), four (11%), three (9%) and two (6%) control subjects showed bell-shaped, tower-shaped, plateau, staccato and interrupted patterns, respectively; the remaining four (11%) could not be analyzed. Residual urine was demonstrated in four (7%) DS children and one (3%) control child. CONCLUSIONS: Lower urinary tract symptoms and abnormal uroflowmetry findings, which can lead to further progressive renal and urinary disorders, are common in DS children. Therefore, lower urinary tract functions should be assessed at the life-long regular medical check-ups for subjects with DS.

Molecular and clinical studies in 138 Japanese patients with Silver-Russell syndrome.

BACKGROUND: Recent studies have revealed relative frequency and characteristic phenotype of two major causative factors for Silver-Russell syndrome (SRS), i.e. epimutation of the H19-differentially methylated region (DMR) and uniparental maternal disomy 7 (upd(7)mat), as well as multilocus methylation abnormalities and positive correlation between methylation index and body and placental sizes in H19-DMR epimutation. Furthermore, rare genomic alterations have been found in a few of patients with idiopathic SRS. Here, we performed molecular and clinical findings in 138 Japanese SRS patients, and examined these matters. METHODOLOGY/PRINCIPAL FINDINGS: We identified H19-DMR epimutation in cases 1-43 (group 1), upd(7)mat in cases 44-52 (group 2), and neither H19-DMR epimutation nor upd(7)mat in cases 53-138 (group 3). Multilocus analysis revealed hyper- or hypomethylated DMRs in 2.4% of examined DMRs in group 1; in particular, an extremely hypomethylated ARHI-DMR was identified in case 13. Oligonucleotide array comparative genomic hybridization identified a ∼3.86 Mb deletion at chromosome 17q24 in case 73. Epigenotype-phenotype analysis revealed that group 1 had more reduced birth length and weight, more preserved birth occipitofrontal circumference (OFC), more frequent body asymmetry and brachydactyly, and less frequent speech delay than group 2. The degree of placental hypoplasia was similar between the two groups. In group 1, the methylation index for the H19-DMR was positively correlated with birth length and weight, present height and weight, and placental weight, but with neither birth nor present OFC. CONCLUSIONS/SIGNIFICANCE: The results are grossly consistent with the previously reported data, although the frequency of epimutations is lower in the Japanese SRS patients than in the Western European SRS patients. Furthermore, the results provide useful information regarding placental hypoplasia in SRS, clinical phenotypes of the hypomethylated ARHI-DMR, and underlying causative factors for idiopathic SRS.

Donepezil significantly improves abilities in daily lives of female Down syndrome patients with severe cognitive impairment: a 24-week randomized, double-blind, placebo-controlled trial.

OBJECTIVE: Down syndrome (DS) patients share certain neuropathological features with Alzheimer disease patients. A randomized, double-blind, placebo-controlled study was performed to investigate the efficacy and safety of donepezil, an Alzheimer disease drug, for DS patients. METHOD: Twenty-one DS patients with severe cognitive impairment were assigned to take donepezil (3 mg daily) or a placebo for 24 weeks, and evaluated for activities in daily lives by concisely modified International Classification of Functioning, Disability and Health (ICF) scaling system. RESULTS: ICF scores significantly increased without any adverse effects in the donepezil group in comparison to those in the placebo control. Among the individual functions tested, there was a dramatic improvement in the global mental functions and in specific mental functions. CONCLUSIONS: Donepezil may effectively and safely improve overall functioning of DS patients with severe cognitive impairment.

Familial brain arteriovenous malformation maps to 5p13-q14, 15q11-q13 or 18p11: linkage analysis with clipped fingernail DNA on high-density SNP array.

Familial arteriovenous malformations (AVM) in the brain is a very rare disease. It is defined as its occurrence in two or more relatives (up to third-degree relatives) in a family without any associated disorders, such as hereditary hemorrhagic telangiectasia. We encountered a Japanese family with brain AVM in which four affected members in four successive generations were observed. One DNA sample extracted from leukocytes of the proband and ten DNA samples from clipped finger nails of other members were available. A genome-wide linkage analysis was performed on this pedigree using Affymetrix GeneCip 10K 2.0 Xba Array and MERLIN software. We obtained sufficient performance of SNP genotyping in the fingernail samples with the mean SNP call rate of 92.49%, and identified 18 regions with positive LOD scores. Haplotype and linkage analyses with microsatellite markers at these regions confirmed three possible disease-responsible regions, i.e., 5p13.2-q14.1, 15q11.2-q13.1 and 18p11.32-p11.22. Sequence analysis was conducted for ten selected candidate genes at 5p13.2-q14.1, such as MAP3K1, DAB2, OCLN, FGF10, ESM1, ITGA1, ITGA2, EGFLAM, ERBB2IP, and PIK3R1, but no causative genetic alteration was detected. This is the first experience of adoption of fingernail DNA to genome-wide, high-density SNP microarray analysis, showing candidate brain AVM susceptible regions.

Transcriptional dysregulation in NIPBL and cohesin mutant human cells.

Cohesin regulates sister chromatid cohesion during the mitotic cell cycle with Nipped-B-Like (NIPBL) facilitating its loading and unloading. In addition to this canonical role, cohesin has also been demonstrated to play a critical role in regulation of gene expression in nondividing cells. Heterozygous mutations in the cohesin regulator NIPBL or cohesin structural components SMC1A and SMC3 result in the multisystem developmental disorder Cornelia de Lange Syndrome (CdLS). Genome-wide assessment of transcription in 16 mutant cell lines from severely affected CdLS probands has identified a unique profile of dysregulated gene expression that was validated in an additional 101 samples and correlates with phenotypic severity. This profile could serve as a diagnostic and classification tool. Cohesin binding analysis demonstrates a preference for intergenic regions suggesting a cis-regulatory function mimicking that of a boundary/insulator interacting protein. However, the binding sites are enriched within the promoter regions of the dysregulated genes and are significantly decreased in CdLS proband, indicating an alternative role of cohesin as a transcription factor.

Molecular karyotyping in 17 patients and mutation screening in 41 patients with Kabuki syndrome.

The Kabuki syndrome (KS, OMIM 147920), also known as the Niikawa-Kuroki syndrome, is a multiple congenital anomaly/mental retardation syndrome characterized by a distinct facial appearance. The cause of KS has been unidentified, even by whole-genome scan with array comparative genomic hybridization (CGH). In recent years, high-resolution oligonucleotide array technologies have enabled us to detect fine copy number alterations. In 17 patients with KS, molecular karyotyping was carried out with GeneChip 250K NspI array (Affymetrix) and Copy Number Analyser for GeneChip (CNAG). It showed seven copy number alterations, three deleted regions and four duplicated regions among the patients, with the exception of registered copy number variants (CNVs). Among the seven loci, only the region of 9q21.11-q21.12 (approximately 1.27 Mb) involved coding genes, namely, transient receptor potential cation channel, subfamily M, member 3 (TRPM3), Kruppel-like factor 9 (KLF9), structural maintenance of chromosomes protein 5 (SMC5) and MAM domain containing 2 (MAMDC2). Mutation screening for the genes detected 10 base substitutions consisting of seven single-nucleotide polymorphisms (SNPs) and three silent mutations in 41 patients with KS. Our study could not show the causative genes for KS, but the locus of 9q21.11-q21.12, in association with a cleft palate, may contribute to the manifestation of KS in the patient. As various platforms on oligonucleotide arrays have been developed, higher resolution platforms will need to be applied to search tiny genomic rearrangements in patients with KS.