Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Autosomal dominant hypocalcemia (ADH) caused by activating mutations of calcium-sensing receptor (CaSR) is characterized by hypocalcemia with inappropriately low concentration of PTH and relative hypercalciuria. Active vitamin D treatment often leads to nephrolithiasis and renal impairment in patients with ADH. However, differential diagnosis between ADH and idiopathic hypoparathyroidism is sometimes very difficult. Here, we report a mutation of CaSR and its functional property found in three generations of a Japanese family. The proband developed seizures at 7 days of age. His mother and elder sister were discovered to have hypoparathyroidism by family survey, but his father was normocalcemic. His grandfather developed heart failure and was found to have hypoparathyroidism. All affected members had been treated with active vitamin D3 and bilateral nephrolithiasis were detected in three of them. DNA sequencing revealed that all affected patients had a heterozygous mutation in CaSR gene that causes proline to leucine substitution at codon 221 (P221L). In vitro functional analysis of the mutant CaSR by measuring inositol 1,4,5-trisphosphate production in response to changes of extracellular Ca indicated that this mutation is an activating one and responsible for ADH in this family. Therefore, careful monitoring of urinary Ca excretion before and during treatment of PTH-deficient hypoparathyroidism is very important, and screening of CaSR mutation should be considered in patients with relative hypercalciuria or with a family history of hypocalcemia.
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PMID:A family of autosomal dominant hypocalcemia with an activating mutation of calcium-sensing receptor gene. 1273 14

A novel missense activating mutation in the extracellular calcium-sensing receptor (CaSR) is reported in this work. It was identified in three related subjects with the phenotypic features of autosomal dominant hypocalcemia (ADH). The proband, a 27-year-old woman, diagnosed as having hypoparathyroidism at 7 years of age and a history of seizures, showed the highest penetrance of the mutation. The remaining two affected members presented asymptomatic chronic hypocalcemia despite severe hypoparathyroidism associated with high levels of serum phosphate and calcium urinary excretion. The missense mutation (Glu(604)Lys) affected an amino acid residue in the C terminus of the cysteine-rich domain of the extracellular amino-terminal domain, which seems to be required for the coupling of ligand binding to the activation of intracellular signaling pathways. This genetic change cosegregated with hypocalcemia in all the individuals where the mutation was found. As parathyroid hormone (PTH) secretion is the regulatory target of the CaSR, polymorphism analysis of the PTH gene was carried out. PTH polymorphisms were analyzed in the kindred studied. Affected members for the Glu(604)Lys CaSR mutation which also carried the uncommon PTH alleles showed higher penetrance of the mutation, with more severe autosomal dominant hypocalcemia. These results suggested that the PTH gene could act as a modifier locus of ADH, affecting the penetrance of the activating CaSR mutation described.
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PMID:A novel mutation in the calcium-sensing receptor responsible for autosomal dominant hypocalcemia in a family with two uncommon parathyroid hormone polymorphisms. 1451 94

A 54-year-old man with a history of generalised tonic clonic seizures presented with complaints of daily unilateral stiffening of the limbs, preceded by paraesthesia. Two years before he had been treated with surgery and radiotherapy for a laryngo-pharyngeal carcinoma. Therefore, epilepsy due to intracerebral metastasis was suggested. However, neither CT nor MRI of the brain (with intravenous contrast) showed any abnormalities and the EEG showed no epileptiform discharges. Laboratory tests revealed elevated levels of thyroid-stimulating hormone in the blood, hypocalcaemia, hyperphosphataemia and hypomagnesaemia. In combination with the medical history, tetany was found to be the correct diagnosis. In this patient, tetany was caused by hypoparathyroidism secondary to surgery and radiotherapy in the neck region. He was treated with levothyroxine, magnesium, calcium, and vitamin D and recovered in a few weeks' time. Hypothyroidism and hypoparathyroidism are common complications after treatment (surgery, radiotherapy and/or chemotherapy) for laryngo-pharyngeal carcinoma and other malignancies in the neck region.
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PMID:[Clinical reasoning and decision making in practice. A man with unilateral attacks of muscular rigidity following neck surgery for a malignant tumor]. 1461 2

Hypoparathyroidism, a life threatening disorder, occurs when insufficient parathyroid hormone is produced to maintain extracellular calcium levels within the normal range. The acute clinical signs and symptoms of hypoparathyroidism are the same as those of hypocalcemia, ranging from tingling to intractable generalized tonic-clonic seizures; therefore, it can be mistaken for epilepsy. We report the case of a 36-year-old man who presented two tonic-clonic seizures, characterized by sudden loss of consciousness with a fall and diffuse tonic contractions and clonic jerks. At first diagnosis of epilepsy was established and therapy with valproate was commenced. In the following days, the patient presented typical signs of hypocalcemia and the diagnosis of hypoparathyroidism was made. In the 4 months follow up, antiepileptic drug therapy was reduced until suspension and calcium supplementation was initiated. We briefly review the most recent reports in the literature.
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PMID:Tonic-clonic seizures in a patient with primary hypoparathyroidism: a case report. 1516 18

Familial hypocalciuric hypercalcemia (FHH) is caused by heterozygous loss-of-function mutations in the calcium-sensing receptor (CASR), in which the lifelong hypercalcemia is generally asymptomatic. Homozygous loss-of-function CASR mutations manifest as neonatal severe hyperparathyroidism (NSHPT), a rare disorder characterized by extreme hypercalcemia and the bony changes of hyperparathyroidism, which occur in infancy. Activating mutations in the CASR gene have been identified in several families with autosomal dominant hypocalcemia (ADH), autosomal dominant hypoparathyroidism, or hypocalcemic hypercalciuria. Individuals with ADH may have mild hypocalcemia and relatively few symptoms. However, in some cases seizures can occur, especially in younger patients, and these often happen during febrile episodes due to intercurrent infection. Thus far, 112 naturally-occurring mutations in the human CASR gene have been reported, of which 80 are unique and 32 are recurrent. To better understand the mutations causing defects in the CASR gene and to define specific regions relevant for ligand-receptor interaction and other receptor functions, the data on mutations were collected and the information was centralized in the CASRdb (www.casrdb.mcgill.ca), which is easily and quickly accessible by search engines for retrieval of specific information. The information can be searched by mutation, genotype-phenotype, clinical data, in vitro analyses, and authors of publications describing the mutations. CASRdb is regularly updated for new mutations and it also provides a mutation submission form to ensure up-to-date information. The home page of this database provides links to different web pages that are relevant to the CASR, as well as disease clinical pages, sequence of the CASR gene exons, and position of mutations in the CASR. The CASRdb will help researchers to better understand and analyze the mutations, and aid in structure-function analyses.
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PMID:CASRdb: calcium-sensing receptor locus-specific database for mutations causing familial (benign) hypocalciuric hypercalcemia, neonatal severe hyperparathyroidism, and autosomal dominant hypocalcemia. 1524 91

Hypoparathyroidism is a relatively common side effect of a thyroidectomy and leads to hypocalcemia. Carpopedal spasm and tetany are typical manifestations and usually occur within weeks after surgery. The first signs can be less typical and include movement disorders such as chorea, as well as symptoms of increased intracranial pressure or epileptic seizures. We describe two cases with generalised tonic-clonic seizures as the first manifestation of postoperative hypoparathyroidism, appearing months and years after thyroidectomy. Iatrogenic hypoparathyroidism needs to be considered in the differential diagnosis of adult-onset, generalised, tonic-clonic seizures even if the thyroidectomy was performed years earlier.
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PMID:Hypocalcemic generalised seizures as a manifestation of iatrogenic hypoparathyroidism months to years after thyroid surgery. 1524 52

Congenital hypoparathyroidism typically manifests with hypocalcemia with or without associated characteristic physical findings and is usually diagnosed during the neonatal period. This report describes an African-American male who was diagnosed at age 32 yr to have dysgenesis of the parathyroid glands due to chromosome 22 microdeletion. Symptomatic hypocalcemia did not develop until age 14 yr, a few weeks after initiation of anticonvulsant therapy for generalized tonic-clonic seizures. Because of the timing for onset of symptomatic hypocalcemia, it was presumed that the patient had anticonvulsant-induced hypocalcemia, and he carried that diagnosis for 18 yr. Chromosome 22q11 deletion syndrome was first suspected at age 32 yr, based on the findings of subtle dysmorphic facial features and a history of learning disability in a patient with PTH-deficient hypocalcemia. The diagnosis was confirmed by fluorescence in situ hybridization analysis. This case underscores the variable clinical presentation of this congenital form of hypoparathyroidism. Chromosome 22q11 microdeletions are relatively common, and the diagnosis should be considered even in adults with hypoparathyroidism because of the potential benefit of genetic counseling.
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PMID:A case of chromosome 22q11 deletion syndrome diagnosed in a 32-year-old man with hypoparathyroidism. 1547 68

The problem of intracranial calcifications in children has not been widely discussed in the literature yet. The aim of this study is to emphasise different clinical aspects of intracranial calcifications found in subcortical nuclei and cerebellum in children with disturbed calcium metabolism. We report three different cases of hypoparathyroidism in children in whom similar radiological changes on computed tomography (CT) of the brain were found. An 11-year-old boy was referred to us after episode of tetany. We confirmed the diagnosis of idiopatic hypoparathyroidism (presence of Chvostek and Trousseau signs, hypocalcemia, hyperphosphatemia, low parathormone serum concentration). On brain CT small, symmetric calcifications in the subcortical nuclei and frontal lobes were imaged. A diagnosis of pseudohypoparathyroidism type Ib in 10-year-old girl was established on the basis of clinical symptoms (syncope with seizures, recurrent carpopedal spasms in the past) and laboratory investigations (hypocalcemia, hyperphosphatemia, high parathormone serum concentration). In 11-year-old girl autoimmune polyglandular syndrome type I was diagnosed (hypoparathyroidism with chronic mucocutaneous candidiasis and nail dystrophy from the age of 2). CT of the brain showed multiple irregular symmetric calcifications in cerebellar hemispheres, internal capsula and subcortical nuclei on the border of white and grey matter in both frontal lobes.
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PMID:[Association of brain computed tomography images of intracranial calcifications in three different cases of hypoparathyroidism]. 1550 18

Mutations in the calcium-sensing receptor gene (CaSR) may result in disorders of calcium homeostasis manifesting as familial benign hypocalciuric hypercalcaemia (FBHH), neonatal severe hyperparathyroidism (NSHPT) or autosomal dominant hypocalcaemia with hypercalciuria (ADHH). FBHH may have a population prevalence as high as one in 16 000, and ADHH one in 70 000. NSHPT is very rare. The FBHH condition is usually asymptomatic. Parathyroidectomy does not result in normal serum calcium, and no active treatment is indicated. To differentiate FBHH from primary hyperparathyroidism (PHPT), a guideline which includes measurement of serum calcium, intact parathyroid hormone (PTH), magnesium and fasting urinary calcium excretion is proposed. Screening of family members for hypercalcaemia, and occasionally a search for mutations in the CaSR gene, may be required. The NSHPT condition may manifest with hypercalcaemia, (usually) very elevated serum PTH concentration, subperiosteal erosions and fractures. Milder cases may be managed medically, but respiratory failure, extreme hypercalcaemia and failure to thrive are indications for early parathyroidectomy. The ADHH condition may result in asymptomatic hypocalcaemia, but some affected family members have minor symptoms, and a minority experience seizures in infancy which can recur into adulthood. A significant proportion of cases previously reported as idiopathic hypoparathyroidism (IHP) may in fact be due to mutations in the CaSR gene. In a moderately hypocalcaemic patient with no other clearly discernible cause, an elevated urine calcium:creatinine ratio is suggestive of ADHH, as is the presence of a first-degree relative with hypocalcaemia. If treatment with vitamin D analogues is undertaken, serum and urine calcium should be monitored, advice which applies equally to ADHH and IHP.
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PMID:Clinical and laboratory features of calcium-sensing receptor disorders: a systematic review. 1558 33

This report describes two cases of Di-George syndrome presenting with hypoparathyroidism in adulthood. The first patient presented with profound hypocalcaemia that resulted in a generalised seizure. Routine investigations revealed hypoparathyroidism. The clue to her underlying condition was the postnatal death of her young child. This case shows that Di-George syndrome can present in adulthood with hypocalcaemia in the absence of other classic features of this condition. This has enormous implications for future family planning and may also have important health implications. The second patient, diagnosed on routine blood testing, had previously suffered with a congenital heart condition, but the syndrome was not revealed until she was of postmenopausal age. These two patients show that Di-George syndrome can present in adulthood with hypocalcaemia. This is an important observation because the condition has profound implications for health and family planning.
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PMID:Di-George syndrome presenting with hypocalcaemia in adulthood: two case reports and a review. 1591 21


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