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

Homocystinuria was studied in 27 patients from 15 families in New South Wales. All 2 had biochemical findings consistent with cystathionine synthetase deficiency. One patient was ascertained by newborn screening, but the remaining index cases were detected because of symptoms: poor eyesight 6, mental retardation 3, thromboses 2, skeletal abnormalities 2, and urinary infection1. 9 patients, one-third of all cases, were mildly affected: either they had no features of the disease, or these did not occur until the late teens. Pyridoxine responsiveness was found in 8 sibships, and clinically there were two distinct kinds of response. For patients born in the decade 1960-69 the ascertainment rate for the total population was 1:58 000. The true incidence must be much higher. Our series indicates that homocystinuria occurs more frequently than has heretofore been thought, and that mild cases are common. It is likely that cases are often missed in current newborn screening programmes.
 ...
PMID:Homocystinuria in New South Wales. 64 32

An international questionnaire survey has been conducted to define better the natural history of homocystinuria due to cystathionine beta-synthase deficiency and permit evaluation of treatment. Data were compiled for 629 patients. Among patients not discovered by newborn screening, B6-responsive individuals on the average have significantly better mental capabilities (mean IQ, 79) than do B6-nonresponsive individuals (mean IQ, 57). Time-to-event curves are presented for the other major clinical abnormalities produced by this disease. Each occurred at significantly lower rates in untreated B6-responsive than in untreated B6-nonresponsive patients, as shown by the following examples: (1) dislocation of optic lenses (at age 10, chances of dislocation: 55% and 82%, respectively); (2) initial clinically detected thromboembolic events (at age 15, chances of having had such an event: 12% and 27%, respectively); (3) radiologic detection of spinal osteoporosis (at age 15, chances of such osteoporosis having been detected: 36% and 64%, respectively); and (4) mortality (at age 30, chances of not surviving: 4% and 23%, respectively). Methionine restriction initiated neonatally prevented mental retardation, retarded the rate of lens dislocation, and may have reduced the incidence of seizures. Pyridoxine treatment of late-detected B6-responsive patients retarded the rate of occurrence of initial thromboembolic events. Following 586 surgical procedures, 25 postoperative thromboembolic complications occurred, six of which were fatal. Reproductive histories were reported predominantly for B6-responsive patients. Living offspring of either men or women patients had few abnormalities. The evidence is inconclusive whether untreated maternal cystathionine beta-synthase deficiency leads to excessive fetal loss. Only 13% of patients detected in screening programs of newborns and classified as to B6-responsiveness were B6-responsive, compared to 47% among late-detected patients. Current screening programs that identify neonatal hypermethioninemia may be preferentially failing to detect B6-responsive patients.
 ...
PMID:The natural history of homocystinuria due to cystathionine beta-synthase deficiency. 387 65

Homocystinuria usually presents with ectopia lentis, mental retardation, thromboembolic complications, and skeletal abnormalities. Whereas neuropsychiatric abnormalities are often recognized in untreated homocystinuria, initial presentation with acute psychosis has only rarely been reported. We describe a previously well 17-year-old adolescent with an acute psychosis characterized by auditory and visual hallucinations and marked paranoia who was found to have pyridoxine-responsive homocystinuria. His mental state normalized within several weeks of inception of pyridoxine and antipsychotic therapy. Pyridoxine-responsive homocystinuria is commonly missed on neonatal screens and should be recognized as a potentially treatable cause of acute psychosis in childhood and adolescence.
 ...
PMID:Homocystinuria presenting as psychosis in an adolescent. 1258 32

Pyridoxine-dependent seizures are an extremely rare genetic disorder. Early diagnosis and treatment are important for the prevention of permanent brain damage. Elevated levels of glutamate and decreased levels of gamma-aminobutyric acid (GABA) in the frontal and parietal cortices are among the characteristic features of this disorder. These metabolic abnormalities eventually lead to seizures and neuronal loss. In this case report, we present magnetic resonance spectroscopy findings of a 9-year-old girl with pyridoxine-dependent seizures with mental retardation. The N-acetylaspartate-to-creatine ratio was found to be decreased in the frontal and parieto-occipital cortices, which could indicate neuronal loss. Magnetic resonance spectroscopy could be a useful tool in the neuroimaging evaluation for assessment of parenchymal changes despite a normal-appearing brain magnetic resonance image in patients with pyridoxine-dependent seizures.
 ...
PMID:Pyridoxine-dependent seizures: magnetic resonance spectroscopy findings. 1503 92