Identical twins with Idiopathic Basal Ganglia Calcification ("Fahr's Disease") presenting with a remarkably similar pattern of neuroimaging findings.

There is a growing interest in defining the genetic background of autosomally dominant inherited Familial Idiopathic Basal Ganglia Calcification (FIBGC), a neuropsychiatric condition often described as ‘‘Fahr’s Disease’’ [1–3]. However, the current debate about the nosology of this heterogeneous phenotype demands a search for standard diagnostic criteria and the identification of loci or mutations responsible for FIBGC that might help to elucidate this intriguing neuropsychiatric condition [4]. The clinical profile includes a variable combination of bothmotor and cognitive impairment, such as parkinsonism, dystonia, tremor, chorea, ataxia, dysphagia, progressive cognitive impairment, psychosis and changes in mood. Neuroimaging may identify calcificationsnot only in thebasal ganglia but also in the thalamus, cerebral white matter, cerebellum and internal capsule, which are always associated with normal biochemical and endocrine screening [1]. Previous neuroradiological analysis in familial brain calcinosis showed that some individuals may have be symptom free despite the presence of extensive findings on neuroimaging; however, studies measuring the total volume of calcification suggest a significantly larger number of deposits in symptomatic individuals compared to asymptomatic subjects [4]. Linkage of FIBGC to a 13.3-cM critical region on chromosome 14 was described for a large American multigenerational family and this locus (IBGC1) is currently being fully sequenced. Another small kindred, from Spain, has also been reported as possibly linked to this locus, narrowing the candidate region to 10.9 cM; however, various others’ families with IBGC have been excluded from the chromosome 14 region, indicating genetic heterogeneity [2,3]. Here we report a small pedigree with a 53-year-old affected male presenting with a history of Poliomyelitis at 7 years of age and subsequent gait and speech impairment. Ten years ago his symptoms increased rapidly and he presented with parkinsonism associated with mood changes and a computerized tomography (CT) revealed extensive bilateral calcifications in basal ganglia and cerebellum. Unfortunately, the images are not available to us. The subject is the father of 23-year-old asymptomatic identical twins each with a strikingly similar pattern of CT-scan findings, including calcification of the basal ganglia, white matter and cerebellum (see Fig. 1). All three subjects were investigated for the main metabolic causes of brain calcifications and the idiopathic etiology was ascertained. These areas of distribution are very typical for IBGC in general; however, previous analysis of familial IBGC shows that the