Abstract: Trichothiodystrophy (TTD) is a hair abnormality that may be associated with a large number of alterations affecting the skin phenotype and skin appendages, nervous system, eyes, bones, and immune, gonadal, and endocrine systems. We report the first case of TTD associated with a urologic malformation and primary hypercaiciuria. Our patient had congenital ichthyosis, physical and mental retardation, and a dysmorphic facies associated with a complex urologic malformation and primary hypercalciuria. Characteristic features of his hair under microscopic examination (trichoschisis, alternating light and dark bands under polarizing microscopy, and a severely defective cuticle) and low sulfur content by radiographic microanalysis confirmed the diagnosis. We discuss the meaning of this new association in the spectrum of abnormalities related to TTD.