Second Case of Type 9 Non-Photosensitive Trichothiodystrophy Caused by Homozygous Variant in the MARS1 Gene.

Trichothiodystrophy exhibits a broad clinical spectrum, and cases with an uncommon phenotype can go unnoticed, complicating the diagnosis. We present the second case of type 9 non-photosensitive trichothiodystrophy caused by a homozygous variant in the MARS1 gene. It presented with atypical features, including long hair, normal hair density of eyebrows and eyelashes, and precocious puberty.