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)

Recent work has shown that in phenylketonuria, PKU, in which phenylalanine accumulates in the blood, the damage to the brain, which so often leads to mental retardation, is not solely due to the large quantities of phenylalanine that enter the brain. The raised levels of phenylalanine in the blood lead to a partial exclusion of various other amino acids from the brain and this exclusion in itself damages the brain. Based on this evidence, that in PKU some amino acids are partially excluded from entering the brain, proposals are made for a modified dietary treatment of this disease. In this diet the phenylalainine is not so greatly reduced as in the standard diet for PKU, whilst supplements of other amino acids are added. The rationale for this new diet is that the partial exclusion from the brain of various amino acids (methionine, tryptophan, histidine, tryosine, isoleucine, leucine and valine) by the raised level of phenylalanine in the blood, acting as a competitive inhibitor, can be largely prevented by increasing the blood levels of these excluded amino acids. Raising slightly their blood levels overcomes the excluding effect of moderately raised levels of phenylalanine in the blood. The advantages of the new diet are that not only is it more palatable than a diet very low in phenylalanine, so that it is more likely to continue to prove acceptable to older children and adolescents, as well as to PKU women who expect to become pregnant, but also that its margin of safety is greater if the patient does take unsuitable food.
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PMID:A new approach to the treatment of phenylketonuria. 719 42

A 5-year-old male with the Aarskog syndrome is described. He had abnormal facies, short stature, short fingers with interdigital webbing, a saddle type scrotum and mild mental retardation. In addition, he had isolated growth hormone deficiency as evidenced by the insulin, arginine, and propranolol-glucagon tests. An arginine test after short-term stimulation with estrogen further supported this diagnosis. His mother had minor abnormalities of the hands and feet, and slight mental retardation.
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PMID:Aarskog syndrome with isolated growth hormone deficiency. 722 81

A male infant showed dysmorphology of the head and face, neck, extremities, and genitalia, as well as growth and mental retardation. His G-banded karyotype was 46,XY,--1+der(1),t(1;16)(q43;q24)mat. Combined with five previously reported cases involving similar terminal deletions beginning at 1q42 or 43, we show that the homology of phenotypic characteristics permits identification of a new deletion syndrome, the first involving chromosome 1.
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PMID:New deletion syndrome: 1q43. 724 46

A case of a 37-year-old male patient with r(15) is reported. At birth he was small and light for dates. His main features are: short stature, head circumference in the lower normal range, mid-facial hypoplasia, radial defects, and mental retardation. Evaluation of the phenotype led us to conclude that a wide spectrum of malformations is possible. There is apparently no strong correlation between karyotype and phenotype.
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PMID:Ring chromosome 15 in a male adult with radial defects. Evaluation of the phenotype. 744 81

We report a patient with mental retardation, behavioral disturbances, and pigmentary anomalies, consistent with the phenotype of hypomelanosis of Ito (HMI), and in whom cytogenetic analysis revealed mosaicism for an unbalanced translocation. His karyotype is 45, XY,-7,-15,+der(7)(7:15)t(q34:q13)/46,XY. He is therefore monosomic for 7q34 to qter and 15pter to q13 in the cells containing the translocation. The human homolog (P) of the p gene (the product of the mouse pink-eyed dilution locus) maps to 15q11q13. Loss of this locus is believed to be associated with abnormalities of pigmentation, such as the hypopigmentation seen in patients with deletions of 15q11q13, and the Prader-Willi and Angelman syndromes. Mutations within the P gene have also been associated with tyrosinase-positive (type II) oculocutaneous albinism. Using fluorescence in situ hybridization, we confirmed that our patient is deleted for one copy of a P gene probe in the cells with the unbalanced translocation, and for loci within the region critical for the Prader-Willi/Angelman syndromes. Although hypomelanosis of Ito is a heterogeneous disorder, we postulate that, in our case and potentially in others, this phenotype may result directly from the loss of specific pigmentation genes.
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PMID:Mosaic loss of 15q11q13 in a patient with hypomelanosis of Ito: is there a role for the P gene? 755 77

Congenital insensitivity to pain with anhidrosis is a rare disorder. Its primary clinical features include congenital analgesia, which leads to self-mutilation; inability to sweat, which leads to defective thermoregulation; and mental retardation. A five-year-old boy with consanguineous parents and no family history of the disorder presented with ulcerating lesions on both knees and elbows. His family had discovered the lack of sensation to pain and anhidrosis. Physical examination revealed ulcers on both knees and elbow, self-mutilation of the tongue, fingers, and toes. Sensation to touch was intact and lacrimation was normal. Moderate mental retardation and analgesia were noted in an otherwise normal neurologic examination. The results of electromyographic examination were normal and the application of pilocarpine showed anhidrosis. A skin biopsy specimen was also examined.
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PMID:Congenital insensitivity to pain with anhidrosis. 768 77

Maple syrup urine disease (MSUD) or branched-chain ketoaciduria is caused by a deficiency of the branched-chain alpha-keto acid dehydrogenase (BCKAD) complex. This results in the accumulation of the branched-chain amino acids (BCAA) and branched-chain alpha-keto acids (BCKA), which often produce severe neurological damage and mental retardation. The present studies focus on mutations in the E1 alpha gene of the BCKAD complex and their effects on the assembly of the E1 decarboxylase component of the enzyme complex. We have developed an efficient histidine-tagged bacterial expression system that allows the folding and assembly of E1 alpha and E1 beta subunits into the E1 heterotetramer (alpha 2 beta 2) in the presence of overexpressed chaperonins GroEL and GroES. The results of pulse-chase experiments with this bacterial expression system showed that a majority of the 15 known E1 alpha mutations, including the prevalent Y393N of Mennonite MSUD patients, decrease the rate of association of normal E1 beta with mutant E1 alpha. This results in limited or no assembly of mutant E1. It is concluded that the carboxy-terminal region of the E1 alpha subunit encoded by exons 7-9 is important for subunit interaction. To stably correct MSUD, we have developed a retroviral vector that contains a normal E1 alpha precursor complementary DNA. Transduction of cultured lymphoblasts from a Mennonite MSUD patient with this recombinant retroviral vector completely restored the rate of decarboxylation of BCKA. The normal decarboxylation activity in transduced MSUD cells remained stable without antibiotic selection during the 14-week study.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Molecular basis of maple syrup urine disease and stable correction by retroviral gene transfer. 778 43

Lesch-Nyhan syndrome is a rare X-linked disease characterized by over-production of uric acid and a central nervous system (CNS) disorder consisting of mental retardation, spasticity, choreoathetosis, and a compulsive form of self-mutilation. A deficiency in hypoxanthine-guanine phosphoribosyl transferase (HPRT) provides the underlying metabolic basis for this disease. A 12 month-old male baby who had orange crystals over the diapers since he was 3 months old was brought to our hospital due to developmental delay. Mental retardation and athetosis were also noted. Chemical analysis revealed hyperuricemia (uric acid 8.6 mg/dl). Urine routine showed microscopic hematuria and uric acid crystals. The activity of HPRT in erythrocyte lysates of parents were both within normal limits, but that of the patient was very low (0.0547 nm/min/mg protein, < 0.05% of control). His younger brother was born 2 months after this disorder diagnosed in this patient. The younger brother was noted to have uric acid crystals over the diapers when he was 40 days old and hyperuricemia (10.6 mg/dl) showed up later. He was also a case of Lesch-Nyhan syndrome since the activity of HPRT in erythrocyte lysates was also low (0.0327 nmol/min/mg protein, < 0.05% of control). Further studies, including carrier detection and deoxyribonucleic acid (DNA) analysis, could be helpful for genetic counseling. This syndrome is rare among Chinese, and this may be due to underdiagnosis.
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PMID:Lesch-Nyhan Syndrome: report on two brothers. 783 90

A six-year-old Japanese boy had ataxia, mental retardation, peripheral neuropathy, proximal myopathy, hearing loss, retinitis pigmentosa and deficiencies in apolipoprotein AI, B, CII and CIII. His clinical features except for hearing loss resembled those of abetalipoproteinaemia or symptomatic hypobetalipoproteinaemia, but his apolipoprotein abnormalities were distinct from these disorders. He had apolipoprotein B-100 with a normal molecular weight. Although most of his neurological manifestations were compatible with those of vitamin E deficiency, their early onset and the presence of hearing loss was unusual for that condition. There has been slight deterioration of ataxia during two years follow-up despite high-dose vitamin E supplementation. Other abnormalities in lipid metabolism might be associated with the neurological damage in this case.
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PMID:A variant form of hypobetalipoproteinaemia associated with ataxia, hearing loss and retinitis pigmentosa. 795 7

We describe a 30-month-old boy with multiple anomalies and mental retardation with hereditary spherocytic anemia. His karyotype was 46,XY,del(8)(p11.23p21.1). Genes for ankyrin and glutathione reductase (GSR) were localized to chromosome areas 8p11.2 and 8p21.1, respectively. Six patients with spherocytic anemia and interstitial deletion of 8p- have been reported. In these patients, severe mental retardation and multiple anomalies are common findings. This is a new contiguous gene syndrome. Lux et al. [1990: Nature 345:736-739] established that ankyrin deficiency and associated deficiencies of spectrin and protein 4.2 were responsible for spherocytosis in this syndrome. We reviewed the manifestations of this syndrome. Patients with spherocytic anemia and multiple congenital anomalies should be investigated by high-resolution chromosomal means to differentiate this syndrome.
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PMID:Hereditary spherocytic anemia with deletion of the short arm of chromosome 8. 853 22


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