Human chromosome 14q32.2 harbors the germline-derived primary DLK1-MEG3 intergenic differentially methylated region (IG-DMR) and the postfertilization-derived secondary MEG3-DMR, together with multiple imprinted genes. Although previous studies in cases with microdeletions and epimutations affecting both DMRs and paternal/maternal uniparental disomy 14-like phenotypes argue for a critical regulatory function of the two DMRs for the 14q32.2 imprinted region, the precise role of the individual DMR remains to be clarified. We studied an infant with upd(14)pat body and placental phenotypes and a heterozygous microdeletion involving the IG-DMR alone (patient 1) and a neonate with upd(14)pat body, but no placental phenotype and a heterozygous microdeletion involving the MEG3-DMR alone (patient 2). The results generated from the analysis of these two patients imply that the IG-DMR and the MEG3-DMR function as imprinting control centers in the placenta and the body, respectively, with a hierarchical interaction for the methylation pattern in the body governed by the IG-DMR. To our knowledge, this is the first study demonstrating an essential long-range imprinting regulatory function for the secondary DMR.

We describe four families with affected siblings showing unique clinical features: early-onset (before 1 year of age) progressive diffuse brain atrophy with regression, postnatal microcephaly, postnatal growth retardation, muscle weakness/atrophy, and respiratory failure. By whole-exome sequencing, we identified biallelic TBCD mutations in eight affected individuals from the four families. TBCD encodes TBCD (tubulin folding co-factor D), which is one of five tubulin-specific chaperones playing a pivotal role in microtubule assembly in all cells. A total of seven mutations were found: five missense mutations, one nonsense, and one splice site mutation resulting in a frameshift. In vitro cell experiments revealed the impaired binding between most mutant TBCD proteins and ARL2, TBCE, and β-tubulin. The in vivo experiments using olfactory projection neurons in Drosophila melanogaster indicated that the TBCD mutations caused loss of function. The wide range of clinical severity seen in this neurodegenerative encephalopathy may result from the residual function of mutant TBCD proteins. Furthermore, the autopsied brain from one deceased individual showed characteristic neurodegenerative findings: cactus and somatic sprout formations in the residual Purkinje cells in the cerebellum, which are also seen in some diseases associated with mitochondrial impairment. Defects of microtubule formation caused by TBCD mutations may underlie the pathomechanism of this neurodegenerative encephalopathy.

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Congenital high airway obstruction syndrome (CHAOS) is a rare life-threatening syndrome. Most cases are diagnosed prenatally by US. We report a fetus with this syndrome that showed a unique course revealed on MRI. Ultrasonography at 22 weeks demonstrated that the fetus had ascites and bilaterally enlarged hyperechoic lungs. Congenital infection, congenital cystic adenomatoid malformation or CHAOS was suspected. Subsequent MRI performed at 24 weeks demonstrated bilaterally enlarged high-signal lungs, dilated bronchi, massive ascites, subcutaneous oedema and polyhydramnios. MRI confirmed the diagnosis of CHAOS. A second MRI at 35 weeks showed that the bilateral lung enlargement, ascites, oedema and polyhydramnios had resolved, but that the appearance of the airway was unchanged. The infant was delivered by caesarean section at 38 weeks of gestation and immediate tracheostomy was performed. This spontaneous regression was explained by a tracheo-oesophageal fistula that may have decreased the intrathoracic pressure.

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Thyroxine supplementation for transient hypothyroxinemia of prematurity may reduce the incidence of CP in extremely preterm infants. Large-scale randomized controlled trials are essential to determine the effects of thyroxine supplementation in reducing the incidence of CP among extremely preterm infants.

We report here a very rare case of de novo inversion-duplication chromosomal abnormality with a pure 3qter duplication syndrome. Interestingly, the 3q duplication includes an overlap of the syndromes critical region. Although there have only been 9 cases of this syndrome reported in the past, our patient had more severe neurological abnormalities than anticipated. In this regard, we have gathered the 3q chromosomal duplication abnormalities known to cause pure 3q duplication syndrome to date as a reference for comparisons and we discuss the particulars of our case.