The principal biochemical features of the illness are reduced hair cystine levels, increased copper/zinc ratio, and presence of arginosuccinic acid in the blood and urine.

[2] The key finding is brittle hair with low sulfur content, but alternating dark and light bands under polarizing microscopy, trichoschisis, and absent or defective cuticle are additional important clues for the diagnosis of trichothiodystrophy.

Trichothiodystrophy or TTD is a heterogeneous group of autosomal recessive disorders, characterized by abnormally sulfur deficient brittle hair and accompanied by ichthyosis and other manifestations.

Because the disease appears to be inherited in an autosomal recessive pattern, detection of low-sulfur brittle hair syndrome is also important for genetic counseling.

Close examination demonstrated the scalp hairs were very brittle, coarse, wiry in texture, and broke off quite easily with mechanical trauma such as combing and brushing.