Arhinia, or absence of the nose, is a rare malformation of unknown etiology that is often accompanied by ocular and reproductive defects. Sequencing of 40 people with arhinia revealed that 84% of probands harbor a missense mutation localized to a constrained region of SMCHD1 encompassing the ATPase domain. SMCHD1 mutations cause facioscapulohumeral muscular dystrophy type 2 (FSHD2) via a trans-acting loss-of-function epigenetic mechanism. We discovered shared mutations and comparable DNA hypomethylation patterning between these distinct disorders. CRISPR/Cas9-mediated alteration of smchd1 in zebrafish yielded arhinia-relevant phenotypes. Transcriptome and protein analyses in arhinia probands and controls showed no differences in SMCHD1 mRNA or protein abundance but revealed regulatory changes in genes and pathways associated with craniofacial patterning. Mutations in SMCHD1 thus contribute to distinct phenotypic spectra, from craniofacial malformation and reproductive disorders to muscular dystrophy, which we speculate to be consistent with oligogenic mechanisms resulting in pleiotropic outcomes.
In extension of a previous study, spontaneous and clastogen-induced chromosome damage was analyzed in cultures of peripheral blood lymphocytes from six further patients with Werner syndrome (WS) and six healthy controls. In addition, sister chromatid exchange (SCE) was estimated in four of these cases. Lymphocytes of patients with various other diseases were used for another series of control experiments. Diepoxybutane (DEB), 4-nitroquinoline-1-oxide (NQO), and bleomycin (BLM) were the standard clastogens throughout the study. While the spontaneous frequency of chromosomal breakage was significantly higher in lymphocytes from all the patients than in the control cells, the basis SCE rate was unaffected in WS cells. Sensitivity of WS cells to the chromosome-damaging action of BLM did not differ from that of control cells, and their sensitivity to DEB was slightly greater than that of control lymphocytes. However, NQO induced a more distinct increase of both break and interchange aberrations in the WS cells than in control cells or cells from patients with other diseases. This effect was not found for the SCE rate. Our data demonstrate the exceptional cytogenetic features of this syndrome: Although the spontaneous and the DEB- and NQO-induced chromosomal breakage rate would suggest that WS is like a classic chromosomal instability syndromes, the lack of sensitivity of WS cells to bleomycin and their stable SCE frequency compared with that of control cells clearly delimitate this syndrome from other entities.
Purpose: To analyze a multiflash multifocal electroretinogram in 20 patients with open-angle glaucoma (OAG). Methods: The stimulation sequence consisted of a binary m-sequence (Lmax 200 cd/m2, Lmin <1 cd/m2). Each m-sequence stimulus was followed by three global flashes (luminance: 400 cd/m2) at an interval of 26 ms. Results: The presence of a response to the three global flashes indicated an adaptive effect of the response to the preceding m-sequence stimulus. In the nasal retinal response average the relative amplitude contribution of the response to the second global flash in relation to the other two global flash responses was outside the range of normal (10th–90th percentile) in 10 of 20 OAG patients. Conclusions: The changes in the relative contribution of the response to the second global flash seem indicative of impaired adaptive effects presumably due to inner retinal damage.
Only a limited array of ABC-transporters is functionally expressed in human cornea. The expression pattern of HCE-T cells appears to be widely different from that of the native corneal tissue. Hence, the in vitro model of human cornea, HCE-T, should be used with much caution when predicting transport rates across the human corneal epithelial barrier in vivo.
Devices for three-dimensional picture presentation are at a more advanced developmental stage than devices for three-dimensional picture acquisition. Further research should emphasize the development of new devices for three-dimensional picture acquisition.
Father and son show the full clinical picture of the EEC syndrome with clefting, lobster-like deformities of the hands and ectodermal dysplasia with tear duct atresia and aplasia of the meibomian glands with defective tear film. During childhood, the main handicapping features are the clefting and the hand deformities with their respective multiple operative revisions. During early adulthood, however, the ocular problems become the predominantly handicapping aspects of the EEC syndrome; due to the ectodermal dysplasia, vascularized corneal scarring develops. Tearing and secondary inflammation due to lacrimal duct atresia has to be treated by early dacryocystorhinostomy. As secondary infections promote the development of corneal scars, one should not postpone the operation too long. Infections have to be treated promptly by local antibiotics. Because of the aplasia of the meibomian glands, artificial tear substitution should be given on a regular basis to support the defective tear film. Thus, the development of vascularized corneal scars can perhaps be delayed. Once corneal scarring has developed, perforating keratoplasty has a poor prognosis due to the ectodermal dysplasia, the absence of the meibomian glands and the defective tear film. Three factors lead to the formation of vascularized corneal scars: recurrent infections of lid margins and conjunctiva due to obstructed tear ducts; defective tear film with insufficient lipid phase due to the aplasia of the meibomian glands; and primary corneal epithelial defects in the course of the generalized ectodermal dysplasia.
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