Martin-Bell syndrome

Martin-Bell syndrome or Martin Bell-Renpenning syndrome is a syndrome comprising X-linked mental retardation in children with macroorchidism, prognathism, hypotonia and autism, and a characteristic but variable facies. It appears in boys (homozygous in the first year of life). In puberty there is pronounced growth of testes, abnormal speech pattern, large ears, long face, high-arched palate, and malocclusion. Additional abnormalities may include lordosis, heart defect, pectus excavatum, flat feet, shortening of the tubular bones of the hands, and joint laxity. Heterozygous females have a broad range of dysfunctions.

Martin and Bell in 1943 described a large pedigree without knowledge of the cytogenetic anomaly and without considering the microorchidism. Sutherland in 1977 described a method for a secure and constant «Darstellung» of the fragile point.

Renpenning's syndrome differs from Martin-Bell in the absence of any fragile site on the X-chromosome. Renpenning&#146;s cases (short stature, moderate microcephaly, neurological disorders) were reported in a Dutch Mennonite pedigree from Alberta and Saskatchewan. Escalante's syndrome is the fragile X type. This term has been used in Brazil and other South American countries. {enWP|Martin-Bell syndrome}}