Spec Care Dentist. 2010 Nov-Dec; 30(6): 255-60
Sajnani AK, Yiu CK, King NM

Larsen syndrome is a rare genetic disorder characterized by multiple dislocations of the large joints and characteristic craniofacial abnormalities. It exists in both a severe autosomal recessive form and a mild autosomal dominant variety. To date, only three authors have reported oral findings for this syndrome. This paper describes an 8-year-old Chinese boy with Larsen syndrome who had advanced periodontitis. The need for periodontal therapy and regular monitoring of such patients has been highlighted.

Proc Natl Acad Sci U S A. 2010 Oct 12; 107(41): 17716-20
Carlström M, Larsen FJ, Nyström T, Hezel M, Borniquel S, Weitzberg E, Lundberg JO

The metabolic syndrome is a clustering of risk factors of metabolic origin that increase the risk for cardiovascular disease and type 2 diabetes. A proposed central event in metabolic syndrome is a decrease in the amount of bioavailable nitric oxide (NO) from endothelial NO synthase (eNOS). Recently, an alternative pathway for NO formation in mammals was described where inorganic nitrate, a supposedly inert NO oxidation product and unwanted dietary constituent, is serially reduced to nitrite and then NO and other bioactive nitrogen oxides. Here we show that several features of metabolic syndrome that develop in eNOS-deficient mice can be reversed by dietary supplementation with sodium nitrate, in amounts similar to those derived from eNOS under normal conditions. In humans, this dose corresponds to a rich intake of vegetables, the dominant dietary nitrate source. Nitrate administration increased tissue and plasma levels of bioactive nitrogen oxides. Moreover, chronic nitrate treatment reduced visceral fat accumulation and circulating levels of triglycerides and reversed the prediabetic phenotype in these animals. In rats, chronic nitrate treatment reduced blood pressure and this effect was also present during NOS inhibition. Our results show that dietary nitrate fuels a nitrate-nitrite-NO pathway that can partly compensate for disturbances in endogenous NO generation from eNOS. These findings may have implications for novel nutrition-based preventive and therapeutic strategies against cardiovascular disease and type 2 diabetes.

Am J Med Genet A. 2010 Oct; 152A(10): 2543-9
Unger S, Lausch E, Rossi A, Mégarbané A, Sillence D, Alcausin M, Aytes A, Mendoza-Londono R, Nampoothiri S, Afroze B, Hall B, Lo IF, Lam ST, Hoefele J, Rost I, Wakeling E, Mangold E, Godbole K, Vatanavicharn N, Franco LM, Chandler K, Hollander S, Velten T, Reicherter K, Spranger J, Robertson S, Bonafé L, Zabel B, Superti-Furga A

We recently reported on the deficiency of carbohydrate sulfotransferase 3 (CHST3; chondroitin-6-sulfotransferase) in six subjects diagnosed with recessive Larsen syndrome or humero-spinal dysostosis [Hermanns et al. (2008); Am J Hum Genet 82:1368-1374]. Since then, we have identified 17 additional families with CHST3 mutations and we report here on a series of 24 patients in 23 families. The diagnostic hypothesis prior to molecular analysis had been: Larsen syndrome (15 families), humero-spinal dysostosis (four cases), chondrodysplasia with multiple dislocations (CDMD "Megarbane type"; two cases), Desbuquois syndrome (one case), and spondylo-epiphyseal dysplasia (one case). In spite of the different diagnostic labels, the clinical features in these patients were similar and included dislocation of the knees and/or hips at birth, clubfoot, elbow joint dysplasia with subluxation and limited extension, short stature, and progressive kyphosis developing in late childhood. The most useful radiographic clues were the changes of the lumbar vertebrae. Twenty-four different CHST3 mutations were identified; 16 patients had homozygous mutations. We conclude that CHST3 deficiency presents at birth with congenital dislocations of knees, hips, and elbows, and is often diagnosed initially as Larsen syndrome, humero-spinal dysostosis, or chondrodysplasia with dislocations. The incidence of CHST3 deficiency seems to be higher than assumed so far. The clinical and radiographic pattern (joint dislocations, vertebral changes, normal carpal age, lack of facial flattening, and recessive inheritance) is characteristic and distinguishes CHST3 deficiency from other disorders with congenital dislocations such as filamin B-associated dominant Larsen syndrome and Desbuquois syndrome.

J Mol Biol. 2009 Jul 31; 390(5): 1030-47
Sawyer GM, Clark AR, Robertson SP, Sutherland-Smith AJ

Missense mutations in filamin B (FLNB) are associated with the autosomal dominant atelosteogenesis (AO) and the Larsen group of skeletal malformation disorders. These mutations cluster in particular FLNB protein domains and act in a presumptive gain-of-function mechanism. In contrast the loss-of-function disorder, spondylocarpotarsal synostosis syndrome, is characterised by the complete absence of FLNB. One cluster of AO missense mutations is found within the second of two calponin homology (CH) domains that create a functional actin-binding domain (ABD). This N-terminal ABD is required for filamin F-actin crosslinking activity, a crucial aspect of filamin's role of integrating cell-signalling events with cellular scaffolding and mechanoprotection. This study characterises the wild type FLNB ABD and investigates the effects of two disease-associated mutations on the structure and function of the FLNB ABD that could explain a gain-of-function mechanism for the AO diseases. We have determined high-resolution X-ray crystal structures of the human filamin B wild type ABD, plus W148R and M202V mutants. All three structures display the classic compact monomeric conformation for the ABD with the CH1 and CH2 domains in close contact. The conservation of tertiary structure in the presence of these mutations shows that the compact ABD conformation is stable to the sequence substitutions. In solution the mutant ABDs display reduced melting temperatures (by 6-7 degrees C) as determined by differential scanning fluorimetry. Characterisation of the wild type and mutant ABD F-actin binding activities via co-sedimentation assays shows that the mutant FLNB ABDs have increased F-actin binding affinities, with dissociation constants of 2.0 microM (W148R) and 0.56 microM (M202V), compared to the wild type ABD K(d) of 7.0 microM. The increased F-actin binding affinity of the mutants presents a biochemical mechanism that differentiates the autosomal dominant gain-of-function FLNB disorders from those that arise through the complete loss of FLNB protein.

Turk J Pediatr. 2008 Jul-Aug; 50(4): 395-9
Orhan D, Balci S, Deren O, Utine EG, Başaran A, Kale G

Larsen syndrome is characterized by multiple joint dislocations, associated with a typical facial appearance and frequently other abnormalities. Both dominant and recessive patterns of inheritance have been reported. A lethal form of Larsen syndrome (Larsen-like syndrome) has been described as a combination of the Larsen phenotype and pulmonary hypoplasia. In this report, we present a 24-week-old female fetus with a possible prenatal diagnosis of thanatophoric dysplasia in whom postmortem examination revealed lethal type Larsen-like syndrome associated with bifid tongue, severe micrognathia and non-immune hydrops fetalis. These findings have not been reported previously in the lethal type Larsen syndrome.

Circulation. 2003 Apr 1; 107(12): 1626-31
Tankó LB, Bagger YZ, Alexandersen P, Larsen PJ, Christiansen C

Although several lines of evidence point to an atherogenic role of central fat mass (CFM), few data are available to address the specific role played by peripheral fat mass (PFM).This study was a cross-sectional analysis of 1356 women aged 60 to 85 years. Study variables were physical measures, CFM and PFM measured by DEXA, aortic calcification (AC) graded on lateral radiographs, lipid and glucose metabolites, blood pressure, and information on lifestyle factors and coronary disease. Peripheral fat mass showed independent negative correlation with both atherogenic metabolic risk factors and AC (P<0.001). The most severe insulin resistance-dyslipidemic syndrome and AC (score 5.10+/-0.76) was found in women with high central fat percentage (CF%, 21.7+/-0.2%) and low peripheral fat percentage (PF%, 18.3+/-0.2%, n=48). The least severe AC (score 2.45+/-0.31) was found in obese women with high CF% (21.6+/-0.1%) and high PF% (27.3+/-0.14%, n=112). The insulin resistance-dyslipidemic syndrome was also less severe compared with those with the same CF% but low PF%. The most favorable metabolic profile characterized women with low CF% (11.56+/-0.16%) and high PF% (26.86+/-0.33%, n=44). In women with a history of myocardial infarct (18.41+/-0.55%, n=45), CF% was significantly higher compared with women with no manifest coronary disease (16.48+/-0.12%, n=1210) without differences in PF%.In elderly women, localization of fat mass is apparently more important for atherosclerosis than obesity per se; although CFM is associated with atherogenic tendencies, PFM seems to exhibit an independent dominant antiatherogenic effect.

Am J Med Genet. 1999 Mar 5; 83(1): 28-42
Schultz C, Langer LO, Laxova R, Pauli RM

We describe two additional instances of atelosteogenesis, type III, in a woman and her son. Clinical and radiographic information concerning these individuals allows further definition of this rare skeletal dysplasia. This is the first documentation of survival to adulthood of an individual with this disorder, of prenatal diagnostic assessment of an affected individual, and of vertical transmission suggestive of autosomal dominant inheritance. The clinical and radiologic phenotype of atelosteogenesis, type III overlaps with that of another skeletal dysplasia, autosomal dominant Larsen syndrome; these most likely represent allelic conditions.

Am J Med Genet. 1997 Dec 12; 73(2): 132-8
Nishimura G, Horiuchi T, Kim OH, Sasamoto Y

We report on 2 cases of otopalatodigital syndrome type II (OPD II) with atypical skeletal changes, overlapping those of boomerang dysplasia, atelosteogenesis type I (AO I) and type III (AO III), and the lethal male phenotype of Melnick-Needles syndrome. One patient exhibited strikingly broad, bowed femora, which resembled those of boomerang dysplasia. The other patient possessed conspicuous undertubulation of the long bones, defective ossification of the spine, and severe undermineralization of the calvaria, which may have caused diagnostic confusion with AO I, AO III, and the lethal male phenotype of Melnick-Needles syndrome. OPD II is transmitted as an X-linked recessive trait, whereas AO I, AO III, and boomerang dysplasia are considered to result from a new dominant mutation, and Melnick-Needles syndrome is inherited as an X-linked dominant trait. Accordingly, differential diagnosis is mandatory to provide the affected families with adequate genetic counseling. Awareness of these skeletal changes in OPD II will prevent the misdiagnosis of this entity as other disorders. Furthermore, the phenotypic overlap among these disorders may expand the entities that constitute the OPD-Larsen dysplasia family proposed by Spranger [1985].

Clin Genet. 1997 Jun; 51(6): 408-11
Kurtoglu S, Dundar M, Hallaç IK, Uzüm K, Okumuş Y, Oktem T

Larsen's syndrome is characterised by multiple joint dislocations, flat face and talipes equinovarus. There is an autosomal dominant form and also a more severe autosomal recessive form. Several types of polycystic kidney disease have been reported in children. In this report we present an infant with a severe form of Larsen's syndrome (thought to be lethal Larsen-like), infantile-type polycystic kidney disease, biliary dysgenesis and osteosclerosis.

Genet Couns. 1997; 8(2): 133-7
Alembik Y, Stoll C, Messer J

We report two familial cases of oto-palato-digital (OPD) Type II syndrome, a father and his son. This family shows that OPDII syndrome is inherited as an autosomal dominant condition. The similarities between the OPDII syndrome and the Larsen syndrome are discussed.

Cancer Genet Cytogenet. 1990 Nov 1; 50(1): 139-48
Svendsen LB, Thorup J, Larsen JK, Bülow S, Horn T

In vitro tetraploidy (IVT) in skin fibroblasts cultures measured by flow cytometry was compared with histological type and degree of dysplasia in 22 patients with adenomas of the colon and rectum. Furthermore, IVT was compared with stage and differentiation in 36 patients with carcinoma of the colon and rectum. In vitro tetraploidy in skin fibroblasts was correlated to type as well as dysplasia in adenomas and differentiation in carcinomas but was not correlated to Dukes' stage in carcinomas. Skin fibroblast genetic instability, expressed as increased IVT (IVT+), has been reported to reflect a genetic predisposition to colorectal cancer in the hereditary nonpolyposis colorectal cancer syndrome. Because IVT+, which appears to be associated with the progression of adenomas to carcinomas, also is found in many of the non-syndrome colorectal cancers, we suggest that development of colorectal cancer is considerably influenced by the constitutive genetic instability of the autosomal dominant colorectal cancer syndromes.

Am J Med Genet. 1986 Jun; 24(2): 219-30
Maroteaux P, Frézal J, Cohen-Solal L

We address the confusion in the current classification of inherited disorders of collagen and the excessive extension of the concept of the Ehlers-Danlos "syndrome" that tends to cover many facts and conditions frequently without strong clinical connection. We propose to subdivide the collagen disorders into four main classes depending on whether skin, joints, bone, or blood vessels are mainly involved. The class with mainly skin involvement includes the different forms of cutis laxa, Ehlers-Danlos syndrome types I and II (autosomal dominant), types V and IX (X-linked recessive), type VI (autosomal recessive), and type VIII (autosomal dominant). The group with mainly articular involvement includes Larsen and related syndromes and other types with a more benign course. The conditions with mainly skeletal involvement include the different forms of osteogenesis imperfecta. The class with mainly blood vessel involvement includes disorders of type III collagen and the Marfan syndrome. This tentative classification proposes a logical clinical framework that will allow easier integration of molecular biology data.