Protein instability associated with AARS1 and MARS1 mutations causes trichothiodystrophy

Area of Science:

• Genetics
• Molecular Biology
• Developmental Biology

Background:

• Trichothiodystrophy (TTD) is a rare neurodevelopmental disorder characterized by brittle hair and nails.
• Photosensitive TTD (PS-TTD) involves progressive neuropathy and accelerated aging, linked to genome maintenance and transcription defects.
• Non-photosensitive TTD (NPS-TTD) forms have variable features without premature aging signs.

Observation:

• Previous research identified gene defects in various gene expression steps for NPS-TTD.
• This study investigates novel genetic causes for NPS-TTD.
• Alanyl-tRNA synthetase 1 and methionyl-tRNA synthetase 1 variants are identified as new causes of NPS-TTD.

Findings:

• Identified alanyl-tRNA synthetase 1 and methionyl-tRNA synthetase 1 variants cause NPS-TTD.
• These variants lead to instability of the encoded alanyl- and methionyl-tRNA synthetase proteins.
• Functional studies show impaired tRNA charging, a crucial step in protein translation.

Implications:

• Protein instability is a common feature across TTD forms.
• TTD affects multiple stages of gene expression, including transcription and translation.
• This expands the definition of TTD to encompass instability of gene expression-related proteins.