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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bardet-Biedl syndrome (BBS) is an uncommon autosomal recessive condition characterized by mental retardation, post-axial polydactylia, obesity and pigmentary retinopathy. We performed linkage analysis in 31 multiplex BBS families and report significant linkage with two markers on chromosome 11q, PYGM and AFM164zf12 (D11S913). Homogeneity testing demonstrates genetic heterogeneity within our set of families. Our data imply that a major gene, BBS1, is located on chromosome 11q, although mutations at other loci may also be associated with this phenotype.
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PMID:Bardet-Biedl syndrome is linked to DNA markers on chromosome 11q and is genetically heterogeneous. 807 32

The Bardet-Biedl syndrome (BBS), which consists of polydactyly, obesity, mental retardation, pigmentary retinopathy and hypogonadism has been known since 1922, but due to the great similarity to the clinical manifestations of the Laurence-Moon syndrome (LMS) there is a considerable terminological confusion in the medical literature. An attempt is made at clarifying the problem. Four children from two families have been observed. There were inter- and intrafamilial variabilities of the expression and severity of the particular features, but retinopathy and structural and/or functional abnormalities were found in 100%. The combination of the two can serve as an easy clinical screening for diagnosis of the disease. Renal involvement is considered to be a cardinal feature of the syndrome. The most common and earliest symptoms are polydypso-polyuria and reduced concentrating ability, which may lead to some diagnostic difficulties, especially in infancy. Three children have end-stage renal disease and two of them are on maintenance haemodialysis, which they tolerate well.
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PMID:Clinical aspects of renal involvement in Bardet-Biedl syndrome. 827 Mar 81

Bardet-Biedl syndrome is an autosomal recessive disorder characterized by mental retardation, obesity, retinitis pigmentosa, polydactyly and hypogonadism. Other findings include hypertension, diabetes mellitus and renal and cardiovascular anomalies. We have performed a genome-wide search for linkage in a large inbred Bedouin family. Pairwise analysis established linkage with the locus D16S408 with no recombination and a lod score of 4.2. A multilocus lod score of 5.3 was observed. By demonstrating homozygosity, in all affected individuals, for the same allele of marker D16S408, further support for linkage is found, and the utility of homozygosity mapping using inbred families is demonstrated. In a second family, linkage was excluded at this locus, suggesting non-allelic genetic heterogeneity in this disorder.
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PMID:Linkage of Bardet-Biedl syndrome to chromosome 16q and evidence for non-allelic genetic heterogeneity. 829 49

Bardet-Biedl syndrome (BBS) is an autosomal-recessive disorder of mental retardation, obesity, retinal dystrophy, polydactyly, and hypogenitalism. Renal and cardiac abnormalities are also frequent in this disorder. Previous clinical suggestions of heterogeneity of BBS were confirmed recently by the identification of four different chromosome loci linked to the disease. In this study we compared clinical manifestations of the syndrome in patients from 3 unrelated, extended Arab-Bedouin kindreds which were used for the linkage mapping of the BBS loci to chromosomes 3, 15, and 16. The observed differences included the limb distribution of the postaxial polydactyly and the extent and age-association of obesity. It appears that the chromosome 3 locus is associated with polydactyly of all four limbs, while polydactyly of the chromosome 15 type is mostly confined to the hands. On the other hand, the chromosome 15 type is associated with early-onset morbid obesity, while the chromosome 16 type appears to present the "leanest" form of BBS. Future cloning of the various BB genes will contribute to the understanding of the molecular basis of limb development and to the identification of human obesity-related genes.
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PMID:Phenotypic differences among patients with Bardet-Biedl syndrome linked to three different chromosome loci. 858 86

This paper reports a clinical and roentgenological examination of the teeth, jaws and saliva of 29 Scandinavian individuals with Laurence-Moon-Bardet-Biedl (LMBB) syndrome, whose cardinal signs are retinal dystrophy, polydactyly, obesity, hypogenitalism and mental retardation. All subjects had at least three of these signs, including retinal dystrophy. Compared with normal subjects, the group had statistically significantly higher frequencies of hypodontia, small teeth and short roots. In addition, the saliva showed a buffering capacity higher than normal. In conclusion, there seem to exist disturbances of both dental and skeletal formation in the LMBB syndrome.
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PMID:Anomalies in the permanent dentition and other oral findings in 29 individuals with Laurence-Moon-Bardet-Biedl syndrome. 866 62

The autosomal recessive disorder Bardet-Biedl syndrome is characterised by retinal degeneration, polydactyly, obesity, mental retardation, hypogenitalism, renal dysplasia, and short stature. It is heterogeneous with at least four gene loci (BBS1-4) having been mapped to date. We have studied 18 multiply affected families noting the presence of both major and minor manifestations. Using a fluorescently based PCR technique, we genotyped each family member and assigned linkage to one of the four loci. Given this degree of heterogeneity we hoped to find phenotypic differences between linkage categories. We found 44% of families linked to 11q13 (BBS1) and 17% linked to 16q21 (BBS2). Only one family was linked to 15q22 (BBS4) and none to 3p12. We conclude that BBS1 is the major locus among white Bardet-Biedl patients and that BBS3 is extremely rare. Only subtle phenotypic differences were observed, the most striking of which was a finding of taller affected offspring compared with their parents in the BBS1 category. Affected subjects in the BBS2 and 4 groups were significantly shorter than their parents. Twenty eight percent of pedigrees did not show linkage to any known locus, evidence for at least a fifth gene. We conclude that the different genes responsible for Bardet-Biedl syndrome may influence growth characteristics such as height.
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PMID:Bardet-Biedl syndrome: a molecular and phenotypic study of 18 families. 903 82

Biemond syndrome type 2 (BS2) is classically regarded as a recessively inherited condition (MIM 210350) comprising mental retardation, coloboma, obesity, polydactyly, hypogonadism, hydrocephalus, and facial dysostosis. Clinically, the disorder is closely related to Bardet-Biedl syndrome. Few cases have been reported, most of them before 1970. We present clinical data on three mentally retarded sporadic cases with coloboma, obesity, and hypogenitalism (in two of them), fitting as first glance a diagnosis of BS2. A review documents striking clinical variability among the patients said to have BS2. We propose a new nosology of those cases and delineate several new clinical forms. Purported BS2 cases may be divided into: (1) Bardet-Biedl syndrome with fortuitous coloboma or aniridia, (2) BS2 sensu stricto, a recessively inherited syndrome of sexual infantilism, short stature, coloboma, and preaxial polydactyly without obesity, only known from the original report, (3) a "new" dominantly inherited form of colobomatous microphthalmia occasionally associated with obesity, hypogonadism, and mental retardation, to which our observations belong. (4) cytogenetically proven Rubinstein-Taybi syndrome (one case), (5) an unclassifiable, early lethal familial syndrome resembling Buntinx-Majewski syndrome, and (6) a "new" coloboma-zygodactyly-clefting syndrome. The latter two syndromes may result from chromosomal anomaly.
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PMID:Coloboma, mental retardation, hypogonadism, and obesity: critical review of the so-called Biemond syndrome type 2, updated nosology, and delineation of three "new" syndromes. 909 85

Bardet-Biedl syndrome (BBS) is a clinically and genetically heterogeneous autosomal recessive disorder characterized by retinitis pigmentosa, polydactyly, obesity, hypogenitalism, mental retardation, and renal anomalies. To detect linkage to BBS loci, 29 BBS families, of mixed but predominantly European ethnic origin, were typed with 37 microsatellite markers on chromosomes 2, 3, 11, 15, 16, and 17. The results show that an estimated 36-56% of the families are linked to the 11q13 chromosomal site (BBS1) previously described by M. Leppert et al. (1994, Nature Genet. 7, 108-112), with the gene order cen-D11S480-5 cM-BBS1-3 cM-D11S913/D11S987-qter. A further 32-35% of the families are linked to the BBS4 locus, reported by R. Carmi et al. (1995, Hum. Mol. Genet. 4, 9-13) in chromosomal region 15q22.3-q23, with the gene order cen-D15S125-5 cM-BBS4-2 cM-D15S131/D15S204-qter. Three consanguineous BBS families are homozygous for three adjacent chromosome 15 markers, consistent with identity by descent for this region. In one of these families haplotype analysis supports a localization for BBS4 between D15S131 and D15S114, a distance of about 2 cM. Weak evidence of linkage to the 16q21 (BBS2) region reported by A. E. Kwitek-Black et al. (1993, Nature Genet. 5, 392-396) was observed in 24-27% of families with the gene order cen-D16S408-2 cM-BBS2-5 cM-D16S400. A fourth group of families, estimated at 8%, are unlinked to all three of the above loci, showing that at least one other BBS locus remains to be found. No evidence of linkage was found to markers on chromosome 3, corresponding to the BBS3 locus, reported by V. C. Sheffield et al. (1994, Hum. Mol. Genet. 3, 1331-1335), or on chromosome 2 or 17, arguing against the involvement of a BBS locus in a patient with a t(2;17) translocation.
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PMID:Linkage mapping in 29 Bardet-Biedl syndrome families confirms loci in chromosomal regions 11q13, 15q22.3-q23, and 16q21. 912 87

Constitutional obesity and mental retardation cooccur in several multiple congenital anomaly syndromes, including Prader-Willi syndrome, Bardet-Biedl syndrome, Cohen syndrome, Albright hereditary osteodystrophy, and Borjeson-Forssman-Lehmann syndrome as well as some rarer disorders. Although hypothalamic-pituitary axis abnormalities are thought to be a possible causative mechanism in some of these disorders, current knowledge is insufficient to explain the pathophysiologic mechanism of obesity in most multiple congenital anomaly/mental retardation syndromes. The chromosomal location of many of these syndromes is known, and studies are ongoing to identify the causative genes. Further delineation of the functions of the underlying genes will likely be instructive regarding mechanisms of appetite, satiety, and obesity in the general population. This review details current knowledge of the clinical and molecular genetic findings of multiple congenital anomaly/mental retardation syndromes associated with intrinsic obesity in an effort to delineate causative mechanisms and genetic abnormalities contributing to obesity.
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PMID:Prader-Willi and other syndromes associated with obesity and mental retardation. 951 59

There are at least five distinct Bardet-Biedl syndrome (BBS) loci, four of which have been mapped: 11q (BBS1), 16q (BBS2), 3p (BBS3), and 15q (BBS4). A comparative study of the three Arab-Bedouin kindreds used to map the BBS2, BBS3, and BBS4 loci suggests that the variability in the number and severity of clinical manifestations, particularly the pattern of polydactyly, reflects chromosome-specific subtypes of BBS [Carmi et al., 1995a; Am J Med Genet 59:199-203]. We describe a Newfoundland kindred of northern European descent and confirm the initial finding of a BBS locus on chromosome 3. However, the "BBS3 phenotype," which includes polydactyly of all four limbs and a progression to morbid obesity, was not observed. Rather, four of the five BBS patients in this family had polydactyly restricted to their feet. The obesity in these patients was reversible with caloric restriction and/or exercise. Mental retardation has been considered a major symptom of BBS. However, formal IQ testing shows that these patients are of average intelligence. Haplotype analysis reduces the BBS3 critical region to a 6-cM interval between D3S1595-D3S1753.
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PMID:Canadian Bardet-Biedl syndrome family reduces the critical region of BBS3 (3p) and presents with a variable phenotype. 971 14


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