Frame shift mutation of LHX1 is associated with Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome.

BACKGROUND: The Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is characterized by congenital aplasia of the uterus and the upper part of the vagina in women who usually have normal ovaries and a 46, XX karyotype. MRKH can occur as an isolated form (type I) or in combination with various malformations as a syndromic or a type II MRKH. To date, in most of the cases the underlying etiology remains unclear. Recently, in approximately 6% of MRKH patients, deletions of chromosomal region 17q12 have been identified. The LHX1 gene, which is located in the deletion interval, has been suggested to be a strong candidate, because targeting inactivation of Lhx1 causes a complex phenotype including aplasia of the Müllerian ducts. METHODS AND RESULTS: By sequence analysis of LHX1 in a large cohort of MRKH patients, we detected a heterozygous frame shift mutation resulting in a premature stop codon. Previously, we have reported a heterozygous missense mutation of LHX1 in another MRKH patient. CONCLUSIONS: We conclude that heterozygous mutations of LHX1 might be one cause of the MRKH syndrome in a subgroup of patients.

Collagen degradation products modulate matrix metalloproteinase expression in cultured articular chondrocytes.

Destruction of collagen within osteoarthritic cartilage depends in part on collagen-degrading matrix metalloproteases (MMP). Degradative fragments of type II collagen (Col II) occur in normal and in osteoarthritic cartilage, and may contribute to regulation of matrix turnover by interfering with normal cell-matrix communication pathways. Therefore, the effects of different types of collagen fragments on mRNA and protein levels of MMP-2, MMP-3, MMP-9, and MMP-13 in cultured bovine articular knee chondrocytes and explants were examined. Primary chondrocytes and explants were incubated with fragments from whole cartilage collagen matrix (Colf) and from purified type II collagen (Col2f), or with a synthetic 29-mer peptide representing the amino-terminal domain of type II collagen (Ntelo). Gelatin zymography revealed increases of proMMP-2, a shift towards active MMP-2 and increases in proMMP-9, depending on the type of fragment. In situ hybridization of cartilage sections displayed MMP-3 mRNA in virtually all cells. Moderate to strong increases in MMP-2, MMP-3, MMP-9, and MMP-13 mRNA levels were detected by quantitative PCR. The results demonstrate stimulating effects of collagen fragments on both mRNA and/or protein from MMP -2, -3, -9, and -13, and suggest a novel mechanism of MMP induction and activation that includes a particular role for N-telo in controlling catabolic pathways of matrix turnover.