[P1-160] Phenotypic spectrum of IBA57 mutations, another candidate gene for cavitating leukoencephalopathy
IBA57 encodes the mitochondrial Fe/S protein assembly factor, specifically involved in biogenesis of mitochondrial [4Fe-4S] proteins. Only 18 cases with variable phenotypes were reported so far. We classified the phenotype into three subtypes, congenital, infantile and childhood.
We performed a long term follow-up study in 11 Chinese patients with IBA57 mutations identified by whole-exome sequencing. MRI features were delineated.
All patients presented with acute/subacute motor regression at median of 9 months (5-15m). Spasticity and symmetric pyramidal tract signs were noticed. Prodromal nonspecific infection was observed in 67%. Motor symptoms gradually aggravated until 1-3 months after disease onset, followed by stabilization and improvements in all cases. Mild recurrence in the case of infections was found in 20%. At the last follow-up, the median interval after the disease onset was 3 years (5m-10y). The motor function was classified as GMFCSI-II in 50% of cases, and GMFCSIII-IV in the other. 30% showed vision impairment. The brain MRI showed characteristic features of cavitating leukoencephalopathy. The high signals in DWI were always observed in any phase of disease, with remarkable decrease after acute stage. Eight novel IBA57 mutations were identified in this study.
A spectrum of phenotypes may be presented in patients with IBA57 mutation. IBA57 should be considered as one of candidates in infantile onset cavitating leukoencephalopathies.
We performed a long term follow-up study in 11 Chinese patients with IBA57 mutations identified by whole-exome sequencing. MRI features were delineated.
All patients presented with acute/subacute motor regression at median of 9 months (5-15m). Spasticity and symmetric pyramidal tract signs were noticed. Prodromal nonspecific infection was observed in 67%. Motor symptoms gradually aggravated until 1-3 months after disease onset, followed by stabilization and improvements in all cases. Mild recurrence in the case of infections was found in 20%. At the last follow-up, the median interval after the disease onset was 3 years (5m-10y). The motor function was classified as GMFCSI-II in 50% of cases, and GMFCSIII-IV in the other. 30% showed vision impairment. The brain MRI showed characteristic features of cavitating leukoencephalopathy. The high signals in DWI were always observed in any phase of disease, with remarkable decrease after acute stage. Eight novel IBA57 mutations were identified in this study.
A spectrum of phenotypes may be presented in patients with IBA57 mutation. IBA57 should be considered as one of candidates in infantile onset cavitating leukoencephalopathies.