A further case of AFG2B-related neurodevelopmental disorder with hearing loss and microcephaly allows further clarification of pathogenicity of the variant c.1313T>C, p.(Leu438Pro)

Abstract

Background: Bi-allelic variants in AFG2B (previously known as SPATA5L1) have recently been associated with a neurodevelopmental disorder with hearing loss and spasticity, as well as isolated hearing loss. We report on a 6 1/2-year-old girl with a history of global developmental delay, subsequent intellectual disability without relevant language acquisition, sensorineural hearing loss, muscular hypotonia and microcephaly.

Methods: We performed trio exome sequencing on the patient and her parents.

Results: Trio exome sequencing revealed likely pathogenic compound heterozygous missense variants in AFG2B [c.527G>T, p.(Gly176Val) and c.1313T>C, p.(Leu438Pro)] in the patient.

Conclusion: Of note, the change c.1313T>C, p.(Leu438Pro) has been observed in a previously published patient as part of a complex disease allele along with a second homozygous missense change, so the exact contribution of the two alterations to this patient's disease had initially remained unclear. Our results support the pathogenic relevance of the c.1313T>C, p.(Leu438Pro) allele while providing detailed insights into the disease manifestation of a further patient.

Keywords: AFG2B; neurodevelopmental disorder; trio exome sequencing.