Brachydactyly type A3 is caused by a novel 13 bp HOXD13 frameshift deletion in a Chinese family

Brachydactyly type A (BDA) is defined as short middle phalanges of the affected digits and is subdivided into four types (BDA1‐4). To date, the molecular cause is unknown. However, there is some evidence that pathogenic variants of HOXD13 could be associated with BDA3 and BDA4. Here, we report a Chinese autosomal dominant BDA3 pedigree with a novel HOXD13 mutation. The affected individuals presented with an obviously shorter fifth middle phalanx. The radial side of the middle phalanx was shorter than the ulnar side, and the terminal phalanx of the fifth finger inclined radially and formed classical clinodactyly. Interestingly, the index finger was normal. The initial diagnosis was BDA3. However, the distal third and fourth middle phalanges were also slightly affected, resulting in mild radial clinodactyly. Both feet showed shortening of the middle phalanges, which were fused to the distal phalanges of the second to the fifth toes, as reported in BDA4. Therefore, this pedigree had combined BDA3 and atypical BDA4. By direct sequencing, a 13 bp deletion within exon 1 of HOXD13 (NM_000523.4: c.708_720del13; NP_000514.2: p.Gly237fs) was identified. The 13 bp deletion resulted in a frameshift and premature termination of HOXD13. This study provides further evidences that variants in HOXD13 cause BDA3‐BDA4 phenotypes.     

Is MED13L-related intellectual disability a recognizable syndrome?

Introduction

MED13L-related intellectual disability is characterized by moderate intellectual disability (ID), speech impairment, and dysmorphic facial features. We present 8 patients with MED13L-related intellectual disability and review the literature for phenotypical and genetic aspects of previously described patients.

Distinction between papillary thyroid hyperplasia and papillary thyroid carcinoma by immunohistochemical staining for cytokeratin 19, galectin-3, and HBME-1

The histopathology of papillary thyroid hyperplasia and papillary thyroid carcinoma is similar enough to cause a diagnostic dilemma in a few cases. Both lesions may have papillary fronds with fibrovascular cores, nuclear crowding, and nuclear anisocytosis. Formalin-fixed paraffin-embedded tissues from 30 randomly selected patients with papillary thyroid hyperplasia and an equal number from patients with papillary thyroid carcinoma were analyzed for expression of cytokeratin 19 (CK19), galectin-3, and HBME-1. Cases of papillary thyroid carcinoma had moderate to strong CK19, galectin-3, and HBME-1 reactivity although both CK19 and galectin-3 showed positive staining in a significant number of nonneoplastic thyroid cases. HBME-1 was uncommon in the nonneoplastic cases. These results indicate that HBME-1 may be useful in helping to distinguish papillary thyroid carcinoma from hyperplasia in diagnostically difficult cases.     

<Emphasis Type="Italic">GPC5</Emphasis> is a possible target for the 13q31-q32 amplification detected in lymphoma cell lines

Comparative genomic hybridization (CGH) analyses have detected gains of copy number on 13q, especially at 13q31-q32, in cell lines and primary cases of various types of lymphoma. Since amplification of chromosomal DNA is one of the mechanisms that can activate tumor-associated genes, and because 13q amplification had been reported in various other types of tumors as well, we attempted to define by fluorescence in situ hybridization (FISH) a common region at 13q31-q32 in which to explore genes that might be targets for the amplification events. Although the commonly amplified region we defined was relatively large (approximately 4 Mb), only one true gene, GPC5, was found there. GPC5 was over-expressed in lymphoma cell lines that had shown amplification, in comparison with those that had not. Our findings suggest that GPC5 is a likely target for amplification, and that over-expression of this gene may contribute to development and/or progression of lymphomas and other tumors.     

Mast cell–derived IL-13 downregulates IL-12 production by skin dendritic cells to inhibit the TH1 cell response to cutaneous antigen exposure

1. Download : Download high-res image (242KB)
2. Download : Download full-size image

     

Adult Still's disease reflects a Th2 rather than a Th1 cytokine profile

Adult Still's disease (ASD) is a chronic multisystemic disease. Extraordinarily high serum levels of IL-18 in ASD patients have been described, whereas the mechanism remains to be clarified. This study aimed to evaluate proinflammatory cytokines and to consider their pathological roles. In patients with rheumatic diseases (n = 151), blood samples were taken at the active phase and the serum levels of IL-18 and other proinflammatory cytokines were measured by ELISA. The extra-high levels of IL-18 were confirmed selectively in ASD patients (n = 10). In the active phase of ASD patients, the levels of IL-6 were elevated accordingly, but IL-1beta and TNF-alpha were undetectable. As to Th1-Th2 cytokines, the levels of IL-4 and IL-13, but not INF-gamma, IL-12, or IL-2, were elevated in all ASD patients examined. Moreover, the serum levels of IL-18 showed a good correlation with those of IL-4, suggesting that ASD reflects a Th2 rather than a Th1 cytokine profile.     

De novo 13q partial duplication identified by cytogenetic, biochemical and molecular approaches

A 3.5-month-old female infant manifesting dysmorphic facies, developmental delay and failure to thrive was referred for cytogenetic evaluation. Peripheral lymphocytes revealed three chromosomally distinct cell lines: 46,XX/46,XX,10p+/47,XX,10p+,+mar. Dermal fibroblasts revealed only the 46,XX,10p+cell line. High resolution G-, R-, and Q-banding suggested that the extra chromosomal material (10p+) represented a duplication of the segment 13q14----13qter. Parental karyotypes were normal. As absolute identification of de novo chromosomal abnormalities, based solely on cytogenetic studies, is sometimes difficult, both biochemical and molecular approaches were undertaken to elucidate this abnormality in more detail. Dosage effects were examined using esterase D (localized to 13q14.1) and the DNA probes p1E8 and p9A7 (localized to 13q22 and 13q31/32, respectively). These studies suggested the presence of only 2 copies of esterase D, but 3 copies of both DNA probes, allowing identification of the breakpoint at 13q14.2.     

Molecular cloning of a novel human gene (SIRP-B2) which encodes a new member of the SIRP/SHPS-1 protein family

A full-length cDNA encoding a novel protein was isolated and sequenced from a human placental cDNA library. This cDNA consists of 1735 base pairs and has a predicted open reading frame (ORF) encoding 354 amino acids. It possesses a putative signal sequence, a long extracellular domain, a transmembrane region, a short intracellular domain, and no catalytic domain, which is highly homologous to signal-regulatory protein (SIRP)-β, suggesting that it seems to be a new member of the SIRP family. Polymerase chain reaction (PCR)-based mapping with both a monochromosomal hybrid panel and radiation hybrid cell panels placed the gene to human chromosome 20p13 near the marker D20S906. Received: August 11, 2000 / Accepted: September 21, 2000     

Effects of interleukin (IL)-13 on immediate-early response gene expression,phenotype and differentiation of human mast cells. Comparison with IL-4

The recently cloned interleukin 13 (IL-13) shares most investigated biological activities on B lymphocytes and monocytes with IL-4. In this study we investigated the potential role of IL-13 in regulating human mast cell activities. The effects of IL-13 on the expression of an immediate-early response gene (c-fos), proliferation, expression of mast cell-associated cell surface antigen (CD54 and Kit), and in vitro differentiation of human mast cells, were investigated. We compared the effect of IL-13 with that of IL-4. Both IL-13 and IL-4 induced expression of c-fos in cells from the human mast cell line HMC-1. This indicates that mast cells express functional receptors for IL-13. IL-13 and IL-4 decreased the proliferation rate of HMC-1 cells. However, IL-13 was less potent than IL-4. Human mast cells constitutively express the adhesion molecule ICAM-1 (CD54) and the receptor for stem cell factor (Kit) (CD117). The expression of CD54 was increased after treatment with IL-13 or IL-4, whereas the expression of Kit was decreased. Also in this action IL-4 was more potent than IL-13. By culturing mononuclear cells from cord blood in the presence of stem cell factor there is a differentiation of tryptase-positive mast cells in the cultures. This process was inhibited when IL-4 was present. In contrast, IL-13 did not affect the expression of tryptase during differentiation of stem cell factor dependent cord blood-derived mast cells. Taken together, these findings indicate that IL-13 has regulatory effects on human mast cells. The effect overlaps with but is also different from that of IL-4.