Trichothiodystrophy: progressive manifestations.

Introduction. Trichothiodystrophy is an autosomal recessive genodermatosis associating congenital dysplasia of the hair and neuroectodermal defects. C linical expression is variable, although abnormalities are generally noted from birth. We report trichothiodystrophy in two brothers with the same phe notype who presented unusual progressive manifestations. Observations. Case 1: A six-year-old boy was seen for vesicular blisters du e to photosensitization. Clinical examination showed dry, brittle, unmanage able hair, discrete koilonychia-type nail defects and an ichthyosiform stal e. The teeth were normal. In addition to psychomotor retardation, the patie nt presented a dysmorphic syndrome (poorly rimmed few-set ears; thick, tria ngular upper lip; scaphocephalic skull; short hands) and congenital bilater al cataract. The diagnosis of trichothiodystrophy was confirmed by a study of DNA repair after exposure to ultraviolet light. A repair defect was foun d similar to that in xeroderma pigmentosum group D. The patient experienced a worsening of psychomotor retardation and episodes of hair loss with edem a and inflammation of the scalp resulting from infections. He also showed m arked asthenia which resolved spontaneously within a few months. Case 2: Th e other brother, born as a collodion baby, presented the same clinical pict ure (cutaneous, exoskeletal, dysmorphic), including congenital bilateral ca taract, photosensitivity and a parenchymatous blister-type pulmonary lesion probably secondary to bronchiectasis. The patient's cutaneous state progre ssively improved. He was seen at six years of age for an episode of inflamm atory edema of the scalp with hair loss. Within six months, all of the hair redrew. The diagnosis of trichothiodystrophy was confirmed by a DNA repair defect after exposure to ultraviolet light. Discussion. Trichothiodystrophy is clinically associated with photosensitiv ity (P), ichthyosis (I), dry, brittle hair (B), intellectual impairment (I) , decreased fertility (D) and short stature (S), which accounts for the acr onym PIBIDS or IBIDS syndrome, depending on whether photosensitivity is inv olved or not (actually in about 50 p. 100 of cases). Other possibly associa ted features include ungueal dysplasias, bilateral cataract, defective teet h, dysmorphic disorders predominant in the ears, neurologic disorders, pulm onary bronchiectasis and recurrent infections. The two cases presented here were thus very symptomatologically complete. The two problems of current c oncern are psychomotor retardation and temporary hair loss as a result of i nfections. The latter has only been described once in the literature. This case was similar to ours since photosensitivity was involved. Analysis of D NA repair also showed a defect after exposure to ultraviolet light similar to that found in xeroderma pigmentosum group D. Thus, episodic hair loss co uld be a symptom characteristic of forms of trichothiodystrophy with a DNA repair defect. However, the explanation for this hair loss is not known. Ot her ectodermal dysplasias can be complicated by hair loss with superinfecti on, such as AEC syndrome (ankyloblepharon, ectodermal dysplasia, cleft pala te).