Genetic heterogeneity in familial idiopathic basal ganglia calcification (Fahr disease)

Intramuscular hemangioma of the temporalis muscle with incidental finding of bilateral symmetric calcification of the basal ganglia: a case report

We report an 11-year-old boy whose brain computed tomography findings incidentally revealed bilateral basal ganglia calcification. He was symptom-free and had no abnormal neurological findings. He was diagnosed with Fahr's disease based on radiological findings and after excluding other etiologies such as infection, metabolic disorders, congenital malformation and malignancies. Most of the reported cases display an autosomal dominant mode of inheritance. Although Fahr's disease is a rare cause of basal ganglia calcification in children, this disease should be considered in children with a family history of neuropsychiatric disorders.

Fahr's disease: variable presentations in a family

Fahr's disease or Striato-pallido-dentate calcification is a well-defined entity with familial or sporadic presentation and approximately two-thirds of the patients are symptomatic. Herein, we report on different manifestations and neuroimaging of six symptomatic members of a family with Fahr's disease. It is significant that three symptom-free members of this family also had brain calcification on brain CT scan. The patients' symptoms had started at different ages with diverse manifestations. The manifestations included extrapyramidal signs, behavioral abnormalities, memory deficits, atonic type of seizure, and ataxia. In further generations, symptoms started earlier.

2q37 as a susceptibility locus for idiopathic basal ganglia calcification (IBGC) in a large South Tyrolean family

Familial idiopathic basal ganglia calcification (FIBGC) is an inherited neurodegenerative disorder characterized by the accumulation of calcium deposits in different brain regions, particularly in the basal ganglia. FIBGC usually follows an autosomal dominant pattern of inheritance. Despite the mapping to chromosome 14q of a susceptibility locus for IBGC (IBCG1) in one family, this locus has been excluded in several others, demonstrating genetic heterogeneity in this disorder. The etiology of this disorder thus remains largely unknown. Using a large extended multigenerational Italian family from South Tyrol with 17 affected in a total of 56 members, we performed a genome-wide linkage analysis in which we were able to exclude linkage to the IBCG1 locus on chromosome 14q and obtain evidence of a novel locus on chromosome 2q37. Electronic supplementary material. The online version of this article (doi:10.1007/s12031-009-9287-3) contains supplementary material, which is available to authorized users.

Linkage studies in familial idiopathic basal ganglia calcification: separating the wheat from the chaff

Idiopathic Basal Ganglia Calcification (IBGC) is a neuropsychiatric condition characterized by brain calcinosis, heterogeneous motor impairment and behavioral symptoms. The IBGC1 locus was the first region linked to this phenotype in an American family, but another kindred from Spain was also reported as possibly associated with this locus. Our group excluded this locus in additional families together with an independent study of an Australian pedigree with IBGC, but without clinical symptoms. Recently, a large Italian family from a population isolate was excluded from IBGC1. However, there are unusual aspects concerning this Tyrolean family, especially if we consider that almost all the clinically affected subjects manifested symptoms and signs suggestive of a dysmorphic syndrome, associated with neuropsychiatric symptoms. Curiously, some of the clinical features in this kindred match with the autosomal dominant chromosomal instability syndrome reported in Japan. Previous studies show that the definition of an autosomal dominant pattern of inheritance is an assumption that might be considered cautiously in familial IBGC, due to the limited clinical penetrance for the brain calcifications and especially when there is no access to all the parents neuroimaging data. Families from an Italian isolate, such as Tyrol, with high inbreeding rates, are more likely to manifest recessive syndromes. Nevertheless, the current debate regarding the nosology of this heterogeneous phenotype demands the establishment of standard diagnostic criteria. The current identification of loci or mutations responsible for FIBGC might help to elucidate this intriguing neuropsychiatric condition.

Familial Fahr disease in a Turkish family

Fahr syndrome refers to a rare syndrome characterized by symmetrical and bilateral intracranial calcification. We present a 42-year-old woman with Fahr disease, but lacking extrapyramidal symptoms or a metabolic disorder. Her neurological examination was normal. Computed tomographic scans demonstrated symmetrical calcification over the basal ganglia, thalamus and cerebellum. No underlying cause for the bilateral calcification was found. When screening other family members, we detected Fahr syndrome in her two daughters and three brothers, revealing that the disease was an autosomal dominant trait. Fahr disease may be clinically asymptomatic, but have pronounced positive brain imaging findings. Computed tomographic scanning remains the most effective screening tool for adult relatives.

Exclusion of linkage to chromosome 14q in a large South Tyrolean family with Idiopathic Basal Ganglia Calcification (IBGC)

Familial Idiopathic Basal Ganglia Calcification (FIBGC) is a neurodegenerative syndrome that usually follows an autosomal dominant pattern of inheritance. Linkage to only one locus on chromosome 14q (IBCG1) has been described so far. We identified and characterized a large multigenerational Italian family from a population isolate with 14 FIBGC affected members. Linkage analysis excluded the IBCG1 locus, thus demonstrating further locus heterogeneity for this disease.

Neuropsychological and 18FDG-PET studies in a family with idiopathic basal ganglia calcifications

Idiopathic basal ganglia calcification (FIBGC) is a rare autosomal dominant neurodegenerative disease, the main clinical signs of which are parkinsonism, cognitive deterioration and/or psychiatric troubles. Familial forms are rare. The underlying basis is not known. We performed detailed neurological, neuropsychological, brain CT scans and MRI evaluations in 15 patients of a large FIBGC family. Three patients also underwent a (18)FDG-PET scan study not previously performed in patients with FIBGC. Basal ganglia calcifications were present in 8 individuals, 3 of which had schizophrenia-like psychosis, cognitive and/or extrapyramidal signs. The mean age at disease onset was 34.0+/-3.6 years. Two patients had moderate executive dysfunction, whereas the proband had more severe dementia. (18)FDG uptake was significantly reduced in striatal or cortical areas, including the precuneus, posterior cingulate and superior temporal gyri. This study shows that calcifications and striatal neuronal degeneration can occur independently, and that functional changes in cortical areas can be observed early in FIBGC. Hypometabolism in the precuneus and posterior cingulate gyrus, which are involved in episodic memory processing, could be responsible for the episodic memory deficit found in the patients. Whether the underlying mechanism involves a neuronal loss or a functional alteration remains to be elucidated.

Severe vascular disturbance in a case of familial brain calcinosis

Here we present the first neuropathological study of a case of autosomal dominant brain calcinosis in a family followed through five generations. The 71-year-old female who came to autopsy had unusually severe and extensive bilateral brain calcifications. The process appeared to start with deposition of minute calcium-positive spheroids of less than 1 mum in diameter in capillaries that otherwise appeared normal. These could be observed extending to areas distant from the main pathology. In more advanced stages, larger spheroids completely covered some capillaries while sparing others. In heavily affected regions, ghost capillaries were observed where only calcium spheroids remained after endothelial cells and basement membranes had disappeared. Vessels of all sizes were affected, and large accretions were observed in the basal ganglia, thalamus and cerebellum. Combined scanning electron microscopy and X-ray spectrometry of these large deposits revealed a dominant presence of calcium and phosphorous, plus carbon and oxygen indicative of organic material, and small amounts of sodium, potassium, sulfur, and magnesium. Reactive astrocytes and reactive microglia accumulated around the calcified deposits, indicating a mild ongoing inflammatory process. The results suggest that severe vascular impairment and mild inflammation contribute to the slow but inexorable progression of hereditary brain calcinosis.