Extensive mongolian spot revealing Hurler's syndrome.

Background. We report a case of a large blue mongolian spot which led to ea rly diagnosis of Hurler's syndrome. This association is uncommon and should be recognized by dermatologists for early diagnosis and management Case report. A male infant from Guinea, born to first-cousin parents, was s een at the age of 4.5 months for multiple, particularly extensive blue mong olian spots. Growth was + 2 SD for age and the infant's psychomotor develop ment was normal. A slight thickening of the skin was noticed without real d ysmorphism. The blue spots extended over the entire posterior aspect and pa rt of the anterior aspect of the trunk and involved all four limbs and the eyelids. The elbow and knee joints were moderately stiff and liver enlargem ent was palpated. The skin biopsy showed fusiform cells with melanin pigmen t tattooing the cytoplasm. No vacuolized epidermal cells were observed. Blo od cell counts and liver and kidney tests were normal. Tests were positive for vacuolized lymphocytes and Gasser lymphocytes. Urine was positive for m ucopolysaccharides and the enzymology study showed an alpha-L-iduronidase d eficiency in serum and leukocytes, confirming the diagnosis of Hurler's dis ease. As no HLA compatible donor was available, no bone marrow graft was at tempted. The child is a candidate for organoid gene therapy. Discussion. Mongolian spots predominate in Asian, American Indian and black population (90% of the cases) compared with Caucasians (10%). The pathogen esis and pathogenic associations are unknown. The incidence of large widesp read mongolian spots is also unknown and no precise criteria are available to define this entity. A few cases of extended mongolian spots associated w ith type 1 gangliosidosis and about 20 cases associated with Hurler's disea se have been reported in the literature. The association with Hurler's dise ase is probably not fortuitous and several hypotheses have been put forward . Bone marrow transplantation can improve prognosis if performed early befo re onset of irreversible visceral disorders,emphasizing the importance of e arly diagnosis in children.