Exclusion of chromosome 9 helps to identify mild variants of acromesomelic dysplasia Maroteaux type
ABSTRACT Acromesomelic dysplasia Maroteaux type (AMDM) is an autosomal recessive disorder belonging to the group of acromesomelic dysplasias. AMDM is characterised by severe dwarfism with shortening of the middle and distal segments of the limbs. An AMDM gene has recently been mapped to human chromosome 9p13-q12 by homozygosity mapping in four consanguineous families. Here, we show linkage of the disease gene to chromosome 9p13-q12 in four of five consanguineous AMDM families and its exclusion in a fifth family with two children affected with a mild form of the disease. This study suggests that genetic heterogeneity accounts for the variable clinical and radiological severity of AMDM.
Full-textDOI: · Available from: André Mégarbané, Aug 13, 2015
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ABSTRACT: Acromesomelic dysplasias are autosomal recessive osteochondrodysplasias. Acromesomelic dysplasia Maroteaux-type (AMDM), also known as St Helena dysplasia, is of two types: The classical and the mild variety. About 50 cases of AMDM have been reported till date, most of them being the classical variety. There is scarcity of literature on anesthesia for such patients. We are reporting a case of general anesthetic management of AMDM, associated with hydrocephalus, Arnold Chiari malformation type-1 and syringomyelia. The patient was a 10-year-old short-statured boy who presented with symptomatic thoracic kyphoscoliosis, gibbus deformity and back pain. On examination, there was no neurological deficit. Radiology revealed thoracic kyphoscoliosis, mild ventriculomegaly and upper cervical syringomyelia. The patient underwent posterior fossa decompression in the prone position under general anesthesia. We will discuss the anesthetic considerations for such patients and review the pertinent literature.Journal of Anaesthesiology Clinical Pharmacology 10/2013; 29(4):555-7. DOI:10.4103/0970-9185.119153
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ABSTRACT: Background The cn/cn dwarf mouse is caused by a loss-of-function mutation in the natriuretic peptide receptor 2 (NPR-2) gene which helps positively regulate endochondral longitudinal bone growth. The gene mutation corresponds to that in the human skeletal dysplasia Acromesomelic Dysplasia Maroteaux type (AMDM). This study assesses histomorphometric, ultrastructural and radiographic correlates of the growth abnormality. Methods Ten litters of cn/cn and cn/+littermates at ages ranging from 2.5 to 6.5 weeks were studied by skeletal radiographs, histomorphometry and physeal ultrastructure. Skeletal radiographs were done on 2 cn/cn and 2 cn/+littermates at 5 weeks of age. Humeral, femoral, and tibial lengths were measured from 34 intact bones (17 cn/cn, 17 cn/+) at 2.5 to 6.5 weeks. Growth plate histomorphometry in 50 bones (26 cn/cn and 24 cn/+) determined the hypertrophic zone/entire physeal cartilage ratios in 204 sections (87 cn/+, 117 cn/cn) at 3 time periods (2.5-3, 4–4.5, and 6–6.5 weeks). Electron microscopy assessed 6 cn/cn and 6 cn/+age and site-matched physeal cartilage. Results Cn/cn mice were two thirds the size of the cn/+. Cn/cn bones were normal in shape or only minimally deformed except for the radius with mid-diaphyseal bowing. Length ratios of cn/cn humeri, femurs, and tibias were a mean of 0.65 (±0.03, n = 34, 17 ratios) compared to cn/+bones. The main physeal abnormality was a markedly shortened hypertrophic zone with the ratio of hypertrophic zone to entire physis 0.17 (±0.063) in the cn/cn and 0.30 (±0.052) in the cn/+mice. Ratio assessments were similar comparing humeral, femoral, and tibial growth plates as were ratios from each of the 3 time periods. Ultrastructural assessments from the resting zone to the lower hypertrophic zone-metaphyseal junction showed no specific individual cell abnormalities in cn/cn compared to cn/+physes. Conclusions The disorder causes a shortened physeal hypertrophic zone but normal ultrastructure of cn/cn chondrocytes points to abnormality primarily affecting the hypertrophic zone rather than a structural cell or matrix synthesis problem.BMC Musculoskeletal Disorders 10/2014; 15(1):347. DOI:10.1186/1471-2474-15-347 · 1.90 Impact Factor