He has
rhizomelic chondrodysplasia punctata (RCDP), an extremely rare and devastating autosomal recessive disorder arising most frequently from a mutation in a gene called
PEX7, which encodes a protein called peroxisomal biogenesis factor 7. The mutation causes impaired function of peroxisomes, which are organelles, or parts of a cell, that have a critical role in the metabolism of fatty acids. Peroxisomes are also where myelination begins, and most peroxisomal disorders, including RCDP, cause severe abnormalities of the central nervous system.
Signs of RCDP include dwarfism with severe shortening of the femora and humeri (rhizomelia), dysmorphic facial features, congenital cataract, spasticity, joint contractures, and profound mental retardation. On x-ray, cartilage has a distinctive stippled appearance (the "chondrodysplasia punctata" part of the disorder's name), caused by abnormal calcification of the bones during early fetal development. Most affected individuals die in infancy or early childhood.