A Chinese CADASIL family with a rare heterozygous mutation in exon 2 of NOTCH3: A case report

Rationale:Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited cerebrovascular disease caused by the neurogenic locus notch homolog protein 3 (NOTCH3) gene mutation. In recent years, most of the newly reported mutations of CADASIL patients mainly occur in exon 3 to 24, while the cases related to exon 2 mutation are rare, and clinical research data are relatively insufficient. In this study, we have reported a case of a rare heterozygous mutation c.128G>A (p.Cys43Tyr) in exon 2 of NOTCH3 in a 41-year-old Chinese man in the light of relevant literatures. Patient concerns:A 41-year-old man who suffered slurred speech for 5 days and right lower limb weakness for 4 days was admitted to our hospital. Diagnoses:Magnetic resonance imaging of the head revealed diffuse white matter lesions involving the outer capsular area and bilateral temporal poles. The rare heterozygous mutation c.128G>A (p.Cys43Tyr) in exon 2 of NOTCH3 was identified through molecular genetic testing. The proband was diagnosed as having CADASIL. Meanwhile, the same mutation was detected in 2 other family members III5 and IV9. Interventions:Atorvastatin calcium tablet (20 mg qd) and aspirin enteric-coated tablet (100 mg qd). Outcomes:The patient was hospitalized for 3 weeks and discharged after his symptoms improved. Lessons:The heterozygous Cys43Tyr mutation in exon 2 of NOTCH3 is rare. Thus, our case report complements the rare mutation of exon 2 and offers additional clinical data for CADASIL patients.