A pediatric case with primary familial brain calcification due to a homozygous variant on the JAM2 gene

İlknur Erol , Leman Tekin Orgun, Şeyda Beşen, Sevcan Tug Bozdoğan , Özlem Alkan

Objective Primary familial brain calcification (PFBC) is a rare neurodegenerative disorder characterized by a combination of neurological,psychiatric and cognitive decline associated with calcium deposition on brain imaging.Recently,biallelic loss-of-function mutations in JAM2 gene reported to be a causes of autosomal recessive form of PFBC (AR- PFBC). Methods A 6-year-old girl was referred to our pediatric neurology department with a generalized-tonic clonic seizure lasting 10 minutes accompanied by fever during a new-onset common cold.She is the first child of consanguineous parents.Family history was non-contributory.Her physical and neurological examination was normal.Her electroencephalography was normal and neurodevelopmental evaluation by Denver Developmental Screening Test was compatible with her age.Cranial MRI revealed heterogeneous hyperintense signal changes on the basal ganglia, dentate nucleus and subcortical white matter on T1-weighted imaging.Laboratory analysis including metabolic, endocrinological, infectious and vasculitic parameters for potential etiology of calcification were all normal. She was diagnosed as idiopathic brain calcification and SLC20A2 and PDGFRB gene anylsis were performed which were normal. However whole-exome analysis (WES) revealed a homozygous variant (c.177_180del (p.R60fs*) on the JAM2 gene consistent with AR- PFBC. Parents were also found to have a heterozygous mutation in the JAM2 gene. Conclusion The JAM2 gen which is the second AR gene associated with intracranial calcification had been reported recently. In the literature, only 11 cases including two children of AR-PFBC with JAM2 gene mutations from different ethnicity have been reported. To the best of our knowledge the present case is the youngest pediatric patient with AR-PFBC due to JAM2 gene mutation in literature.

Keywords: Primary familial brain calcification, Fahr disease, JAM2 gene, childhood

İlknur Erol
Baskent University Faculty of Medicine, Adana Dr. Turgut Noyan Application and Research Center
Turkey

Leman Tekin Orgun
Baskent University Faculty of Medicine, Adana Dr. Turgut Noyan Application and Research Center
Turkey

Şeyda Beşen
Baskent University Faculty of Medicine, Adana Dr. Turgut Noyan Application and Research Center
Turkey

Sevcan Tug Bozdoğan
Cukurova University AGENTEM (Adana Genetic Diseases Diagnosis and Treatment Center) and Medical Genetics Department of Medical Faculty
Turkey

Özlem Alkan
Baskent University Faculty of Medicine, Adana Dr. Turgut Noyan Application and Research Center
Turkey

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Leman Tekin Orgun 
Baskent University Faculty of Medicine, 
Adana Dr. Turgut Noyan Application and Research Center 
Turkey