A 5-year-old boy who was born of nonconsanguineous parentage presented with hypertrichosis and papulonodular lesions on the posterior trunk that had developed at birth and age 1 year, respectively. Cutaneous examination revealed multiple symmetric, skin-colored papulonodules overlying the scapulae and posterior shoulders that gave the appearance of pebbled skin (Figure). In addition to generalized hypertrichosis, physical examination revealed short stature, macrocephaly, coarse facial features (including synophrys), macroglossia, hepatomegaly, and multiple joint contractures. Medical history was notable for developmental delay and hearing deficits. Surgical history was notable for repair of umbilical and inguinal hernias at age 2 years. Family history was noncontributory. A biopsy specimen from a papule on the back revealed extensive deposition of mucin throughout the dermis, separating the collagen bundles. Enzyme analysis revealed low serum iduronate-2-sulphatase (IDS) levels (5.06 nmol/4 hours/mL; normal range, 167-475 nmol/4 hours/mL) and normal total hexosaminidase levels (1124 nmol/hour/mL; normal range, 800-1600 nmol/hour/mL). Two-dimensional echocardiography results showed moderate mitral regurgitation. With this constellation of clinical and laboratory features, a diagnosis of mucopolysaccharidosis type 2 (MPS 2; Hunter syndrome) was established. Molecular genetic testing was not available.