Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028738 (nystagmus)
 7,431 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cases of hypomagnesaemia of hereditary renal origin represent at least three different congenital disorders of tubular reabsorption of magnesium (Mg). Isolated familial hypomagnesaemia has been reported in a heterogeneous group of patients and an autosomal dominant pattern of inheritance has often been found to be present. Familial hypokalaemia-hypomagnesaemia, inherited as an autosomal recessive trait, has been reported in 17 patients and we now describe 3 additional cases. Hypomagnesaemia is accompanied by hypokalaemia, metabolic alkalosis, hypocalciuria and moderate sodium chloride wasting. Titration of renal Mg reabsorption indicates the presence of a low threshold but a normal Tm. The inherited defect is probably situated at the level of the distal convoluted tubule and mimics the therapeutic effect of thiazides. This condition is frequently confused with Bartter's syndrome. Familial hypomagnesaemia-hypercalciuria, also inherited as an autosomal recessive trait, has been reported in at least 15 patients and we now add 3 new cases. Hypomagnesaemia is always accompanied by hypercalciuria and nephrocalcinosis. Ocular abnormalities such as myopia and horizontal nystagmus are often present. Hypermagnesiuria is of a greater degree than that observed in the previous entity and reflects a low Tm of Mg reabsorption. The defect must be situated at the level of the ascending limb of the loop of Henle and affects the transport of both calcium and Mg but not of sodium and chloride. This condition has not been clearly separated from hereditary distal renal tubular acidosis in the literature.
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PMID:Hypomagnesaemia of hereditary renal origin. 315 19

Carbonic anhydrase type II deficiency syndrome is an uncommon autosomal recessive disease with cardinal features including osteopetrosis, renal tubular acidosis and brain calcifications. We describe the neurological, neuro-ophthalmological and neuroradiological features of 23 individuals (10 males, 13 females; ages at final examination 2-29 years) from 10 unrelated consanguineous families with carbonic anhydrase type II deficiency syndrome due to homozygous intron 2 splice site mutation (the 'Arabic mutation'). All patients had osteopetrosis, renal tubular acidosis, developmental delay, short stature and craniofacial disproportion with large cranial vault and broad forehead. Mental retardation was present in approximately two-thirds and varied from mild to severe. General neurological examinations were unremarkable except for one patient with brisk deep tendon reflexes and two with severe mental retardation and spastic quadriparesis. Globes and retinae were normal, but optic nerve involvement was present in 23/46 eyes and was variable in severity, random in occurrence and statistically correlated with degree of optic canal narrowing. Ocular motility was full except for partial ductional limitations in two individuals. Saccadic abnormalities were present in two, while half of these patients had sensory or accommodative strabismus, and seven had congenital nystagmus. These abnormalities were most commonly associated with afferent disturbances, but a minor brainstem component to this disorder remains possible. All internal auditory canals were normal in size, and no patient had clinically significant hearing loss. Neuroimaging was performed in 18 patients and repeated over as long as 10 years. Brain calcification was generally progressive and followed a distinct distribution, involving predominantly basal ganglia and thalami and grey-white matter junction in frontal regions more than posterior regions. At least one child had no brain calcification at age 9 years, indicating that brain calcification may not always be present in carbonic anhydrase type II deficiency syndrome during childhood. Variability of brain calcification, cognitive disturbance and optic nerve involvement may imply additional genetic or epigenetic influences affecting the course of the disease. However, the overall phenotype of the disorder in this group of patients was somewhat less severe than reported previously, raising the possibility that early treatment of systemic acidosis with bicarbonate may be crucial in the outcome of this uncommon autosomal recessive problem.
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PMID:The neurology of carbonic anhydrase type II deficiency syndrome. 2212 Jan 47