Mayer–Rokitansky–Küster–Hauser (MRKH) syndrome, also referred to as Müllerian agenesis, is the second most common cause of primary amenorrhea. It is characterized by congenital absence of the uterus, cervix, and the upper part of the vagina in otherwise phenotypically normal 46,XX females. MRKH syndrome has an incidence of about 1 in 4,500–5,000 newborn females and it is generally divided into two subtypes: MRKH type 1, in which only the upper vagina, cervix and the uterus are affected, and MRKH type 2, which is associated with additional malformations generally affecting the renal and skeletal systems, and also includes MURCS (MÜllerian Renal Cervical Somite) characterized by cervico‐thoracic defects. MRKH syndrome is mainly sporadic; however, familial cases have been described indicating that, at least in a subset of patients, MRKH may be an inherited disorder. The syndrome appears to demonstrate an autosomal dominant inheritance pattern, with incomplete penetrance and variable expressivity. The etiology of MRKH syndrome is still largely unknown, probably because of its intrinsic heterogeneity. Several candidate causative genes have been investigated, but to date only WNT4 has been associated with MRKH with hyperandrogenism. This review summarizes and discusses the clinical features and details progress to date in understanding the genetics of MRKH syndrome.

Human ciliopathies are hereditary conditions caused by defects of proteins expressed at the primary cilium. Among ciliopathies, Joubert syndrome and related disorders (JSRD), Meckel syndrome (MKS) and nephronophthisis (NPH) present clinical and genetic overlap, being allelic at several loci. One of the most interesting gene is TMEM67, encoding the transmembrane protein meckelin. We performed mutation analysis of TMEM67 in 341 probands, including 265 JSRD representative of all clinical subgroups and 76 MKS fetuses. We identified 33 distinct mutations, of which 20 were novel, in 8/10 (80%) JS with liver involvement (COACH phenotype) and 12/76 (16%) MKS fetuses. No mutations were found in other JSRD subtypes, confirming the strong association between TMEM67 mutations and liver involvement. Literature review of all published TMEM67 mutated cases was performed to delineate genotype-phenotype correlates. In particular, comparison of the types of mutations and their distribution along the gene in lethal versus non lethal phenotypes showed in MKS patients a significant enrichment of missense mutations falling in TMEM67 exons 8 to 15, especially when in combination with a truncating mutation. These exons encode for a region of unknown function in the extracellular domain of meckelin. ©2010Wiley-Liss, Inc.

Recent work has demonstrated enhanced X monosomy in women with primary biliary cirrhosis (PBC) as well as two other female-predominant autoimmune diseases, systemic sclerosis and autoimmune thyroid disease. To further our understanding of these events, we have investigated the mechanisms of X chromosome loss and X chromosome inactivation (XCI) in 166 women with PBC and 226 rigorously age-matched healthy and liver disease controls. X chromosome analysis and determination of loss pattern was performed by quantitative fluorescent polymerase chain reaction (QF-PCR) with 4 X-linked short tandem repeats. Further definition of the XCI was based on analysis of methylation-sensitive restriction sites. Importantly, in PBC the X chromosome loss occurs not only more frequently but also in a preferential fashion. This observation supports our thesis that the enhanced X monosomy involves only one parentally derived chromosome and is not secondary to a constitutive non random pattern of XCI. In fact, in the presence of monosomy, the lost X chromosome is necessarily the inactive homologue. Conclusion: The finding that the X chromosome loss is preferential suggests the critical involvement of X chromosome gene products in the female predisposition to PBC and also emphasizes the need to determine the parental origin of the maintained chromosome to investigate the role of imprinting. (HEPATOLOGY 2007;46:456-462.)

Partial duplication of SHOX gene is found in some cases with both familial and sporadic Mayer-Rokitansky-Küster-Hauser type I syndrome.