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).