SNP Shot: Genomic Insights

Mucolipidosis II alpha/beta, also called I-cell disease, is a severe and worsening condition that impacts numerous bodily systems. Sadly, most individuals with this disorder do not live beyond early childhood.

Infants born with mucolipidosis II alpha/beta are typically small, with reduced muscle strength (hypotonia) and a feeble cry. After birth, their growth is slow and usually ceases around the age of two. Developmental milestones are delayed, especially speech and motor skills like sitting and standing.

Bone abnormalities are common in children with mucolipidosis II alpha/beta, often being present at birth. These can include an excessively curved upper back (kyphosis), clubfeet, dislocated hips, unusually shaped long bones, and short hands and fingers. Joint contractures are also present, severely restricting movement. Most children with this condition never learn to walk without assistance. X-rays reveal multiple skeletal abnormalities, a characteristic known as dysostosis multiplex.

Additional symptoms of mucolipidosis II alpha/beta may include a soft bulge near the navel (umbilical hernia) or in the groin area (inguinal hernia), heart valve problems, distinctive, "coarse" facial features, and enlarged gums (gingival hypertrophy). Stiffening of the vocal cords can lead to a hoarse voice. A narrowed airway increases the risk of repeated respiratory infections. Recurrent ear infections are also common and can result in hearing loss.

Inheritance:

Mucolipidosis II alpha/beta is an autosomal recessive disorder. This means that a person must inherit two copies of the mutated gene (one from each parent) to have the condition. The parents, who each carry one copy of the mutated gene, are usually unaffected and show no symptoms.