Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypochondroplasia is an autosomal dominant discrete form of short-limbed dwarfism with roentgenographic changes similar to, but distinctive from, achondroplasia. The patients are normal at birth and in early childhood present with short-limbed dwarfism, thick body build, long trunk, normal head, moderate lumbar lordosis and broad, stubby hands and feet. A high incidence of mental retardation and absence of other neurologic complications is distinctive from achondroplasia. Diagnosis of hypochondroplasia is primarily radiogrpahic. No single diagnostic radiographic sign is present, and thus, a complete radiographic survey of the whole skeleton is required for diagnosis. Pertinent radiographic findings include a normal skull, short, broad long bones with prominent bony sites of muscle attachment, normal growth plate, prominent styloid process of the ulna and lateral malleolus of the fibula, shortened base of the iliac bones, horizontal hypoplastic low-set sacrum and mild narrowing of the interpediculate distance of the lumbar spine. Differential diagnosis is from other types of short-limbed dwarfism, particularly achondroplasia. Kozlowski, an authority on hypochondroplasia, believes this form of short-limbed dwarfism, if carfully searched for, may be more common than achondroplasia.
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PMID:Hypochondroplasia. 115 67

The gene for von Recklinghausen neurofibromatosis (NF1) is on proximal 17q; the location of the gene for achondroplasia (ACH) is unknown. We have begun a molecular analysis of a patient with mental retardation, NF1 and ACH, a clinical presentation suggestive of a contiguous gene syndrome. In addition, this individual has a 47,XYY chromosome constitution. To define a possible chromosome 17 deletion, we investigated the copy number of DNA sequences linked to NF1 with conventional and pulsed-field gel electrophoresis (PFGE). We found no evidence for a deletion on chromosome 17. These results make it unlikely that this patient harbors a single deletion in the NF1 region causing both NF1 and ACH and suggest different mechanisms for the de novo occurrence of 2 autosomal dominant disorders in this individual.
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PMID:Molecular analysis of a patient with neurofibromatosis 1 and achondroplasia. 190 91

We have investigated genetic linkage of von Recklinghausen neurofibromatosis (NF1) and achondroplasia (ACH) using chromosome-17 markers that are known to be linked to NF1. Physical proximity of the two loci was suggested by the report of a patient with mental retardation and the de novo occurrence of both NF1 and ACH. Since the chance of de novo occurrence of these two disorders in one individual is 1 in 600 million, this suggested a chromosomal deletion as a single unifying molecular event and also that the ACH and NF1 loci might be physically close. To test this, we performed linkage analysis on a three-generation family with ACH. We used seven DNA probes that are tightly linked to the NF1 locus, including DNA sequences that are known to flank the NF1 locus on the centromeric and telomeric side. We detected two recombinants between the ACH trait and markers flanking the NF1 locus. In one recombinant, the flanking markers themselves were nonrecombinant. Multi-point linkage analysis excluded the ACH locus from a region surrounding the NF1 locus that spans more than 15 cM (lod score less than -2). Therefore, analysis of this ACH pedigree suggests that the ACH locus is not linked to the NF1 locus on chromosome 17.
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PMID:The achondroplasia gene is not linked to the locus for neurofibromatosis 1 on chromosome 17. 216 5

Thanatophoric dysplasia (TD) is one of the most common neonatal lethal skeletal dysplasias with micromelic shortening of the limbs, relative macrocephaly, flat vertebral bodies and a narrow thorax. TD has been divided into two types, type I (TD1) and II (TD2), based on clinical, radiological, histological, and molecular criteria. We identified a A to T heterozygous base subsitution at position 1949 predicted to cause a Lys650Met substitution in a term infant with TD1. This mutation has been previously described in one case of TD1 and three cases of severe achondroplasia with acanthosis nigricans and mental retardation. Interestingly, all cases with the Lys650Met mutation have the same unusual curvature of the tibia and/or fibula.
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PMID:Lys650Met substitution in the tyrosine kinase domain of the fibroblast growth factor receptor gene causes thanatophoric dysplasia Type I. Mutations in brief no. 199. Online. 1067 Oct 61

Pediatric neurologic diseases are often associated with different kinds of sleep disruption (mainly insomnia, less frequently hypersomnia or parasomnias). Due to the key-role of sleep for development, the effort to ameliorate sleep patterns in these children could have important prognostic benefits. Study of sleep architecture and organization in neurologic disorders could lead to a better comprehension of the pathogenesis and a better treatment of the disorders. This article focuses on the following specific neurologic diseases: nocturnal frontal lobe epilepsy and abnormal motor behaviors of epileptic origin, evaluating differential diagnosis with parasomnias; achondroplasia, confirming the crucial role of craniofacial deformity in determining sleep-disordered breathing; neuromuscular diseases, mainly Duchenne's muscular dystrophy and myotonic dystrophy; cerebral palsy, evaluating either the features of sleep architecture and the importance of the respiratory problems associated; headaches, confirming the strict relationships with sleep in terms of neurochemical and neurobehavioral substrates; and finally a review on the effectiveness of melatonin for sleep problems in children with neurologic syndromes and mental retardation, blindness, and epilepsy.
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PMID:Sleep disorders in children with neurologic diseases. 1176 88