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

The reported incidence of mental retardation in Leber's congenital amaurosis has varied from 10% to 87%. There has been no review of the estimate since it became possible to delineate an increasing number of diagnostic subcategories. In this study, the visual and cognitive development of 38 children with congenital retinal dystrophies has been followed up prospectively. Children with associated disorders in other systems and those with central nervous system malformations or degenerations were significantly more likely to have learning disability than those without additional medical problems. Most subgroups made little or no visual progress with the exception of the group with associated hypoplasia of the cerebellar vermis. The study highlights the importance of using the specialised techniques now available to delineate fully the visual diagnosis and paediatric perspective because of their relevance to cognitive and visual prognosis.
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PMID:Congenital retinal dystrophies: a study of early cognitive and visual development. 137 26

We reexamined 75 children in whom Leber's congenital amaurosis had been previously diagnosed. On review, 30 of these patients had an ocular or systemic disorder other than Leber's congenital amaurosis. The most common of these revised diagnoses were congenital stationary night blindness, achromatopsia, infantile-onset retinitis pigmentosa, Joubert's syndrome, Zellweger syndrome, and infantile Refsum's disease. Of the 45 patients with Leber's congenital amaurosis, mental retardation occurred in six patients, and visual deterioration in six patients. Leber's congenital amaurosis should only be diagnosed if other known ocular and systemic disorders have been carefully excluded.
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PMID:Follow-up and diagnostic reappraisal of 75 patients with Leber's congenital amaurosis. 265 17

Of 99 children in the Royal Blind School, Edinburgh (which serves Scotland and part of N E England), 15 had optic atrophy (hydrocephalus 4, intracranial haemorrhage 2, prematurity 2, fetal distress 2, birth asphyxia 2, cerebral atrophy 1, cardiac arrest during hernia operation 1, and leukaemia 1). Fourteen had congenital cataract, 12 congenital retinal aplasia (Leber's congenital amaurosis) and 11 retinopathy of prematurity. There were small numbers in many other diagnostic categories, including three with non-accidental head injury. Mental retardation, spasticity, and nystagmus were frequent other correlates in all diagnostic categories. 'Very probably hereditary' was a conservative attribution in 36, while 'probable' seemed appropriate for 12-that is, almost 48% were hereditary. Only about 11 cases might have been prevented through genetic counselling, which testifies to the frequency of autosomal recessive hereditary disease, although no parents were consanguineous.
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PMID:Blindness in schoolchildren: importance of heredity, congenital cataract, and prematurity. 365 73

Leber's congenital amaurosis is a hereditary clinical disorder that may be associated with several different diseases. This study consists of a retrospective review of 43 cases. Twenty of our patients had fundus appearances that resembled retinitis pigmentosa. Five had normal-appearing fundi. The remainder had other, previously reported fundus abnormalities, with the exception of two patients who demonstrated a new fundus finding, a nummular pigmentary pattern. Other associated eye anomalies included cataracts, keratoconus, ptosis, and strabismus. The most frequent systemic associations were mental retardation, cystic renal disease, skeletal disorders, and hydrocephalus.
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PMID:Leber's congenital amaurosis. Retrospective review of 43 cases and a new fundus finding in two cases. 382 12

Visual acuity for gratings was studied in 18 infants and children with generalized retinal degenerations using preferential looking (PL) procedures. Diagnoses were Leber's congenital amaurosis (12), Laurence-Moon-Bardet-Biedl-like syndromes (4) and metabolic disorders (2). ERG's were extinguished in 11 patients and much attenuated in seven patients. Acuities at all ages (two months to 12 years) were significantly poorer than normal, and patients with extinguished ERG's had the poorest acuity. Neurological abnormality or mental retardation, present in ten patients, was as likely in patients with 6/60 or poorer grating acuity as in patients with better than 6/60 acuity. A comparison group of 12 infants and children with oculocutaneous albinism showed significantly better grating acuities than the patients with retinal degeneration. Relatively good grating acuity in infants with no anatomic fovea (oculocutaneous albinism) and much poorer acuities of infants with generalized retinal degeneration suggest that parafoveal or peripheral retina is necessary and sufficient for normal, behaviorally-obtained grating acuity in infancy.
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PMID:Visual acuity of infants and children with retinal degenerations. 405 72

We report on a new autosomal-recessive syndrome in 4 Japanese children in 2 families. The key manifestations are Leber congenital amaurosis, short stature, growth hormone insufficiency, mental retardation, hepatic dysfunction, metabolic acidosis, and autosomal-recessive inheritance. There were no consanguineous marriages. Abnormal eye movements were noticed neonatally, and ophthalmological examinations showed no visual acuity, pigmentary retinal degeneration, and nonrecordable electroretinograms in all cases. Inadequate weight gain and short stature gradually became apparent after birth, and at present the height range is -4.6 - -7.2 SD (standard deviations). Developmental delay was noted at age 4 months, and the developmental quotient is 50-70 at present. Deterioration of development and convulsions were not recognized. Elevated serum aminotransferase levels and metabolic acidosis were also found at age 4 months. Proximal renal tubular acidosis was clarified by bicarbonate tolerance tests in 1 case, and may have caused metabolic acidosis. Growth hormone secretion was insufficient by insulin tolerance test in 3 cases. One year of growth hormone therapy in 2 cases did not affect growth velocity. Hepatic dysfunction and metabolic acidosis ameliorated later. No renal cysts were found. A cranial computed tomographic scan and magnetic resonance imaging showed normal findings. Amino acids, organic acids, and very long chain fatty acid levels in plasma were all normal in the 3 cases examined. Histopathological and mitochondrial DNA analyses showed no evidence of mitochondrial disorders.
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PMID:New autosomal-recessive syndrome of Leber congenital amaurosis, short stature, growth hormone insufficiency, mental retardation, hepatic dysfunction, and metabolic acidosis. 926 92

A group of 229 patients with Leber's congenital amaurosis (ACL) was investigated for associated defects. We especially looked for the occurrence of mental retardation because the literature gives varying frequencies for this association. A percentage of 19.8% was found. This finding has consequences for genetic counseling. Special attention was given to how frequently sibling pairs occurred in which one patient was mentally retarded whereas the other functioned normally. We found 11 sibling pairs that were discordant with regard to their mental state. This observation proves that mental retardation could be one variable expression of ACL.
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PMID:Mental retardation in amaurosis congenita of Leber. 1002 47

We summarize 18 mutations in the human CRX gene that have been associated with Leber congenital amaurosis (congenital retinal blindness), cone-rod degeneration, or retinitis pigmentosa. Except for one obviously null allele not definitely associated with a phenotype (a frameshift in codon 9), all CRX mutations appear to be completely penetrant and cause disease in heterozygotes. These dominant alleles fall into two categories. In one group are missense mutations and short, in-frame deletions; in the second group are frameshift mutations, all of which are in the last exon. All of these dominant mutations are likely to produce stable mRNA that is translated. Mutations in the missense group preferentially affect the conserved homeobox (codons 39-98), and all frameshift mutations leave the homeodomain intact but alter the OTX motif encoded by codons 284-295 at the carboxy terminus. We could not uncover any correlation between type of disease (congenital amaurosis vs. cone-rod degeneration or retinitis pigmentosa) and the type of mutation (missense vs. frameshift). Four of the 18 mutations (approximately 20%) were de novo mutations, and all of these were found in isolate cases of Leber congenital amaurosis. Dominant CRX mutations have not been associated with mental retardation or developmental delay that has sometimes been found in Leber congenital amaurosis caused by other genes. Implications regarding potential future therapies are discussed.
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PMID:Dominant Leber congenital amaurosis, cone-rod degeneration, and retinitis pigmentosa caused by mutant versions of the transcription factor CRX. 1174 42

Leber's congenital amaurosis (LCA) is a clinically and genetically heterogeneous disorder characterized by severe loss of vision at birth. It accounts for 10-18% of cases of congenital blindness. Some patients exhibit only blindness of retinal origin whereas others show evidence of a multi-systemic involvement. We review the literature relating to this severe disorder, highlighting unresolved questions, in particular the nature of the association of LCA with mental retardation and with systemic findings and syndromic pictures. In recent years, genetic advances in the diagnosis of LCA have opened up new horizons, also from a therapeutic point of view. A better understanding of this pathology would be valuable for paediatric neurologists.
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PMID:Leber's congenital amaurosis: an update. 1261 70

Joubert syndrome and related disorders comprise a subgroup of ciliopathies defined by the presence of the 'molar tooth sign', a midbrain-hindbrain malformation identifiable by neuroimaging. Characteristically, the corticospinal tract and superior cerebellar peduncles do not decussate. Epileptic seizures are uncommon. We present a case of a 28-year-old man with a background of Leber's congenital amaurosis with nephronophthisis, requiring kidney transplantation, and mental retardation, who developed epileptic seizures consisting of a short muffled cry and involuntary shaking movements of the extremities beginning in the left upper limb; these episodes lasted several seconds and occurred in clusters. Simultaneous video-EEG recording showed an ictal pattern in the left frontal lobe. Brain MRI revealed the pathognomonic 'molar tooth sign'; diffusion tensor imaging (DTI)-tractography showed a lack of decussation of both corticospinal tracts. To the best of our knowledge, this is the first time that DTI-tractography has been used to uncover the anatomical substrate underlying the semiology of epileptic seizures.
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PMID:Uncrossed epileptic seizures in Joubert syndrome. 2600 75


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