Low-Level Germline 48,XYY,+21 Mosaicism Associated with Transient Abnormal Myelopoiesis in a Phenotypically Normal Neonate.

Transient abnormal myelopoiesis (TAM) is a unique neonatal leukemoid reaction caused by a pathognomonic GATA1 mutation in conjunction with the gene dosage effect of trisomy 21, which is either of germline or somatic origin. We encountered a 48,XYY,+21 phenotypically normal neonate with Down syndrome who developed TAM due to cryptic germline mosaicism. Quantification of the mosaic ratio was complicated by an overestimation bias of hyperproliferating TAM within the germline component. To establish a workflow for such a clinical scenario, we analyzed the cytogenetic findings of neonates with TAM associated with somatic or low-level germline mosaicism. We showed that multistep diagnostic procedures (i.e., paired cytogenetic analyses of peripheral blood specimens in culture with or without phytohemagglutinin; serial cytogenetic studies of more than one tissue, such as the buccal membrane; and complementary DNA-based GATA1 mutation screening) can verify the specificity of cytogenetic testing for phenotypically normal neonates with TAM suspected of mosaicism.

Monocyte Chemoattractant Protein-1 (MCP-1) as a Potential Therapeutic Target and a Noninvasive Biomarker of Liver Fibrosis Associated With Transient Myeloproliferative Disorder in Down Syndrome.

Liver fibrosis is one of the common complications of transient myeloproliferative disorder (TMD) in Down syndrome (DS), but the exact molecular pathogenesis is largely unknown. We herein report a neonate of DS with liver fibrosis associated with TMD, in which we performed the serial profibrogenic cytokines analyses. We found the active monocyte chemoattractant protein-1 expression in the affected liver tissue and also found that both serum and urinary monocyte chemoattractant protein-1 concentrations are noninvasive biomarkers of liver fibrosis. We also showed a prospective of the future anticytokine therapy with herbal medicine for the liver fibrosis associated with TMD in DS.

Epilepsy in children with trisomy 18.

Although the reported incidence of epilepsy associated with trisomy 18 is 25-50%, there have been no detailed descriptions of the characteristics of trisomy 18-related epilepsy. We investigated the characteristics of epilepsy in children with trisomy 18 who remained alive for over 1 year by sending questionnaires to pediatric neurologists belonging to the Kyoto Multi-institutional Study Group of Pediatric Neurology. Eleven patients with trisomy 18 were enrolled (age at the study, from 15 to 134 months; median, 43 months), of whom seven (64%) had epilepsy. The age at seizure onset ranged from 1 to 42 months (median: 11 months). Among the seven patients with epilepsy, two had focal epilepsy, four had generalized epilepsy including infantile spasms in three, and the remaining one had an unclassified type. Seizure seminology included complex partial seizures in both the patients with focal epilepsy. At the time of the investigation, three children with generalized epilepsy still had daily seizures, while the remaining four were seizure-free. In conclusion, the characteristics of epilepsy in patients with trisomy 18 were as follows: over half of the children developed epilepsy during infancy or early childhood; infantile spasms might be one of the common epileptic syndromes; the epilepsy was intractable in half of the children, especially in those with generalized epilepsy.

A case of Toriello-Carey syndrome with severe congenital tracheal stenosis.

Toriello-Carey syndrome is rare condition characterized by agenesis of the corpus callosum, the Pierre Robin sequence, and facial anomalies such as telecanthus, short palpebral fissures, and a small nose with anteverted nares [Toriello and Carey, 1988]. In addition, tracheal and laryngeal anomalies are common complications in patients with Toriello-Carey syndrome, and these anomalies can lead to death [Kataoka et al., 2003]. Congenital tracheal stenosis is a life-threatening condition with high mortality. Even if surgery is successful, several serious complications can result in a high risk of mortality. We describe a case of a Japanese boy with Toriello-Carey syndrome who had severe congenital tracheal stenosis, in whom surgical tracheal plasty was avoided because of adequate respiratory care, allowing the patient to be alive at 18 months of age.

Neonatal subpial hemorrhage along the medial side of the temporal lobe: Two case reports.

Neonatal subpial hemorrhage has been underrecognized until recently and its pathophysiology remains unclear. Advances in magnetic resonance imaging have facilitated the identification of hemorrhage within the subpial space and cohort studies recently reported its imaging and clinical features. We encountered two cases of neonatal subpial hemorrhage along the medial side of the temporal lobe. Case 1: A 1-day-old boy had repeated apneic attacks with cyanosis from 2 hours after birth at 39 weeks of gestation by vacuum extraction delivery. Computed tomography and magnetic resonance imaging showed subpial hemorrhage from the medial to caudal side of the right temporal lobe with T2 prolongation in the underlying cerebral parenchyma. Case 2: A 0-day-old boy had repeated apneic attacks with cyanosis from 3 hours after birth at 39 weeks of gestation by vaginal delivery. Subpial hemorrhage was observed from the anterior to medial side of the left temporal lobe on computed tomography and magnetic resonance imaging. On magnetic resonance imaging, the adjacent brain parenchyma showed a hyperintense signal on T2-weighted imaging. No abnormalities or signs of fetal distress were noted in the course of delivery. A mildly prolonged activated partial thromboplastin clotting time, an elevated D-dimer level, and low fibrinogen level were detected in a blood examination after birth in both cases. Both cases had subpial hemorrhage along the medial side of the temporal lobe, which suggested that an external mechanical force with fetal head molding during delivery caused subpial hemorrhage; however, other factors, including coagulopathy, may be involved in its pathophysiology.

Sensitive detection of GATA1 mutations using complementary DNA-based analysis for transient abnormal myelopoiesis associated with the Down syndrome.

INTRODUCTION: GATA1 mutation plays an important role in initiating transient abnormal myelopoiesis (TAM) and in the clonal evolution towards acute megakaryoblastic leukaemia (AMKL) associated with Down syndrome (DS). This study aimed to develop and validate the clinical utility of a complementary DNA (cDNA) analysis in parallel with the conventional genomic DNA (gDNA) Sanger sequencing (Ss), as an initial screening test for GATA1 mutations. METHODS: GATA1 mutations were evaluated using both gDNA and cDNA in 14 DS patients using Ss and fragment analysis (FA), respectively. RESULTS: The detection sensitivity of conventional gDNA sequencing was limited in low blast percentage TAM (LBP-TAM); however, cDNA-based Ss readily detected all the pathognomonic GATA1 mutations. The cDNA-based FA readily detected GATA1 frameshift mutation with a reliable sensitivity ranging from 0.005% to 0.01% of clonal cells. CONCLUSIONS: GATA1 mutations are heterogeneous; therefore, we would like to propose a dual cDNA and gDNA analysis as a standard diagnostic approach, especially for LBP-TAM. cDNA-based FA promises an excellent sensitivity for detecting frameshift GATA1 mutations in the longitudinal clonal evolution towards AMKL without using a patient specific primer.

Two Japanese Patients With SMA Type 1 Suggest that Axonal-SMN May Not Modify the Disease Severity.

BACKGROUND: Spinal muscular atrophy is caused by survival motor neuron gene SMN1 mutations. SMN1 produces a full-length SMN1 protein isoform encoded by exons 1-7, and an axonal-SMN protein isoform encoded by exons 1-3 and intron 3. The axonal-SMN protein is expressed only in the embryonic period and plays a significant role in axonal growth. However, there has been no report on contribution of axonal-SMN to spinal muscular atrophy severity until now. PATIENTS: Two Japanese boys with spinal muscular atrophy type 1 in our study presented with generalized muscle weakness and respiratory insufficiency soon after birth and required an artificial ventilator from early infancy. Patient 1 was compound heterozygous for two SMN1 mutations, whole-gene deletion, and an intragenic mutation (c.819_820insT). He retained one copy of SMN1 producing the N-terminal part of SMN1 including axonal-SMN. On the other hand, patient 2 was homozygous for SMN1 deletion. Both of them showed the same copy number of spinal muscular atrophy-modifying genes, NAIP and SMN2. These findings suggested that the C-terminal domain of full-length SMN1 determined the severity, irrespective of presence or absence of axonal-SMN expression. CONCLUSION: In patient 1, the C-terminal domain of full-length SMN1 determined spinal muscular atrophy severity, rather than the axonal-SMN, one copy of which could be present and intact. The presence or absence of axonal-SMN may not impact disease severity in spinal muscular atrophy type 1 patients.

Intragenic mutations in SMN1 may contribute more significantly to clinical severity than SMN2 copy numbers in some spinal muscular atrophy (SMA) patients.

BACKGROUND: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by deletion or intragenic mutation of SMN1. SMA is classified into several subtypes based on clinical severity. It has been reported that the copy number of SMN2, a highly homologous gene to SMN1, is associated with clinical severity among SMA patients with homozygous deletion of SMN1. The purpose of this study was to clarify the genotype-phenotype relationship among the patients without homozygous deletion of SMN1. METHODS: We performed molecular genetic analyses of SMN1 and SMN2 in 112 Japanese patients diagnosed as having SMA based on the clinical findings. For the patients retaining SMN1, the PCR or RT-PCR products of SMN1 were sequenced to identify the mutation. RESULTS: Out of the 112 patients, 106 patients were homozygous for deletion of SMN1, and six patients were compound heterozygous for deletion of one SMN1 allele and intragenic mutation in the retained SMN1 allele. Four intragenic mutations were identified in the six patients: p.Ala2Val, p.Trp92Ser, p.Thr274TyrfsX32 and p.Tyr277Cys. To the best of our knowledge, all mutations except p.Trp92Ser were novel mutations which had never been previously reported. According to our observation, clinical severity of the six patients was determined by the type and location of the mutation rather than SMN2 copy number. CONCLUSION: SMN2 copy number is not always associated with clinical severity of SMA patients, especially SMA patients retaining one SMN1 allele.