ADAMTS10 mutations in autosomal recessive Weill-Marchesani syndrome

Abstract

Weill-Marchesani syndrome (WMS) is characterized by the association of short stature; brachydactyly; joint stiffness; eye anomalies, including microspherophakia and ectopia of the lenses; and, occasionally, heart defects. We have recently mapped a gene for the autosomal recessive form of WMS to chromosome 19p13.3-p13.2, in a 12.4-cM interval. Here, we report null mutations in a member of the extracellular matrix protease family, the gene encoding ADAMTS10, a disintegrin and metalloprotease with thrombospondin motifs. A total of three distinct mutations were identified in two consanguineous families and in one sporadic WMS case, including one nonsense mutation (R237X) and two splice mutations (1190+1G-->A and 810+1G-->A). ADAMTS10 expression studies using reverse-transcriptase polymerase chain reaction, northern blot, and dot-blot analyses showed that ADAMTS10 is expressed in skin, fetal chondrocytes, and fetal and adult heart. Moreover, electron microscopy and immunological studies of the skin fibroblasts from the patients confirmed impairment of the extracellular matrix. We conclude, therefore, that ADAMTS10 plays a major role in growth and in skin, lens, and heart development in humans.

Figure 1

Structure of the ADAMTS10 gene. The three mutations are located in the metalloprotease domain.

Figure 2

ADAMTS10 mutations and segregation of flanking markers in the two consanguineous families

Figure 3

A, Northern analysis of the ADAMTS10 gene in various human fetal tissues. Note the presence of three distinct transcripts, of 5.5, 2.0, and 1.7 kb, probably corresponding to alternative splicing of the same RNA transcript. B, Human multiple-tissue expression array of ADAMTS10. 1A–1H, 2A–2H, and 3B, Brain. 4A, Heart. 4B, Aorta. 4C, Atrium, left. 4D, Atrium, right. 4G, Intraventricular septum. 4H, Apex of the heart. 5A–5H and 6A–6C, Digestive tract. 5B, Stomach. 7A, Kidney. 7B, Skeletal muscle. 8D–8G, Genitourinary tissues. 9A, Liver. 9B, Pancreas. 9E, Salivatory gland. 10A–10H, Leukemia and malignant cell lines. 11A, Fetal brain. 11B, Fetal heart. 11C, Fetal kidney. 11D, Fetal liver. 11E, Fetal spleen. 11F, Fetal thymus. 11G, Fetal lung. C, RT-PCR detection of ADAMTS10 RNA in skin fibroblasts from patient 2, control fibroblasts, and control fetal chondrocytes. The specific transcript is detected in fibroblasts and chondrocytes. Note the abnormal size and weak signal of ADAMTS10 transcript in patient 2, corresponding to unstable mRNA.

Figure 4

Actin organization in the cultured fibroblasts of patients and controls (Phalloidin-Alexa staining). Note the reduced intensity of actin staining in control cells and the large actin bundles in a long cytoplasmic extension of patient fibroblasts.