Abstract

Background: The aim of this study is to highlight the characteristic radiographic features observed in newborns affected by mucolipidosis type 2 (MLII).

Case Report: A preterm male neonate was admitted to the Neonatal Intensive Care Unit due to prematurity and respiratory distress. The antenatal ultrasound revealed unspecified skeletal abnormalities and intrauterine growth retardation. At birth, he presented with coarse facial features, gingival hyperplasia, shortening of both upper and lower limbs, joint limitation, hip dislocation, and chest deformity. The diagnosis of mucolipidosis type 2 (MLII) (OMIM #252500), a rare autosomal recessive lysosomal disorder, was immediately suspected with a total body x-ray because of the distinctive radiographic features of the disease. X-ray highlighted severe generalized osteopenia, shortening of the proximal segments of both the upper and the lower limbs, extensive cloaking of the right femur, abnormally large and cup-shaped metaphyses with irregular demineralization, resorption of the clavicle, bowing of long bones, vertebral body rounding, altered hip morphology and stippling of the talocalcaneal bones.

Conclusions: The clinical diagnosis of MLII can be challenging in newborns due to phenotypic overlap with other lysosomal disorders, including mucopolysaccharidosis type 1 (MPS I, Hurler disease), gangliosidosis type I (GM I), infantile galactosialidosis, infantile sialidosis (MLI, mucolipidosis I), and infantile free sialic storage disease. Cloaking of the femora is an early, almost diagnostic, radiographic abnormality observed in newborn patients affected by MLII. Recognizing the specific association of anomalies of MLII helps rule out differential diagnosis and establish appropriate diagnosis, care, and parental counselling.