Carpal tunnel syndrome is the most common peripheral neuropathy in adults but remains a very rare condition in children. Lysosomal overload diseases (mucopolysaccharidosis and mucolipidosis), anatomical abnormalities, trauma and familial forms are the most frequent aetiologies. No studies report idiopathic forms. We present the case of a 14-year-old girl with Mucopolysaccharidosis type I (MPS I) in its moderate form with multi-visceral involvement. She had a history of a right sunken thumb operated on at a young age. Presenting with bilateral carpal tunnel syndrome more predominant and deficient on the right, confirmed by ultrasound and electromyography (EMG). The patient under went median nerve neurosis with a conventional approach. No complications were observed, we obtained a sensitive recovery at S4, on the motor level the patient is improving and at 6 months follow-up we obtained a motor score of M3. Carpal tunnel syndrome in children is rare. The clinical picture is not very noisy. It is a serious pathology because it can lead to significant motor sequela. It is therefore necessary to be vigilant and to have easy recourse to complementary examinations (electromyography, ultrasound). For our team, the therapeutic attitude is that of systematic open surgical treatment.