A family study of autosomal recessive primary familial brain calcification caused by JAM2 gene mutation and literature review / 中华神经科杂志

ABSTRACT

Objective:To improve the clinician′s recognition of the clinical and molecular characteristics of primary familial brain calcification (PFBC).Methods:The detailed clinical information, imaging and molecular characteristics were analyzed in proband and family members of a genetically confirmed autosomal recessive PFBC family. The clinical and imaging features of junctional adhesion molecule 2 (JAM2) gene related PFBC were analyzed in combination with the literature review.Results:The proband was a 32-year-old man, with slurred speech and paroxysmal limb twitch as the first symptoms, accompanied by cognitive dysfunction, and rigidity in the limbs, with epilepsy in the past. Brain CT showed extensive, symmetrical, and bilateral calcification involving the cerebellum, basal ganglia, thalamus, subcortex and cortex. Other family members showed no related clinical symptoms. Brain CT of the parents of the proband showed no calcification. Gene testing of the proband revealed a homozygous c.685C>T(p.R229*) mutation in JAM2 gene, which has been reported as a pathogenic variation abroad, whereas has not been reported in China. The proband′s parents and children were found with heterozygous c.685C>T (p.R229*) mutation.Conclusions:Autosomal recessive inherited PFBC is a rare disease, and JAM2 mutation is a newly discovered pathogenic gene of PFBC in 2020. Patients with intracranial calcification should be alert of JAM2 gene mutation.