Multisystem developmental disorder

Not to be confused with Multiple complex developmental disorder.

Multisystem developmental disorder (MSDD) is a term used by Stanley Greenspan to describe children under age 3 who exhibit signs of impaired communication as in autism, but with strong emotional attachments atypical of autism.^{[citation needed]} It is described in the DC:0-3R manual as an optional diagnosis for children under two years of age.^[1][2]

Other uses of the term

The term multisystem developmental disorder has also been used to describe various developmental disorders. These include:

• Alagille syndrome,^[3] an autosomal dominant disorder with a wide range of features and manifestations. Its five most significant features are chronic cholestasis, a condition where bile cannot flow from the liver to the duodenum, occurring in 95% of cases; heart abnormalities (over 90%); butterfly vertebrae; posterior embryotoxon and a distinctive face (prominent forehead, deep-set eyes, and a pointed chin).^[4]
• Rubinstein-Taybi syndrome,^[5][6] a syndrome characterized by broad thumbs, facial abnormalities, and big toes alongside moderate to severe intellectual disability.^[7]
• Williams syndrome,^[8][9] a neurodevelopmental disorder characterized by a unique profile of strengths and deficits; most with the condition have mild intellectual disability but have grammatical and lexical abilities above what would be expected from their IQs.^[10] They are hypersocial and empathetic, but social isolation is commonly experienced.^[11]
• Proteus syndrome,^[12] a congenital disorder causing disproportionate growth of skin, bone, and other tissues.^[13]
• Asphyxiating thoracic dysplasia,^[14] an autosomal recessive skeletal disorder with an estimated prevalence of between 1 in 100,000 and 1 in 130,000 live births.^[15]

Symptoms

• Toe walking^[16]
• Pragmatic speech problems^[16]
• Clumsiness^[16]
• Obsessions and rituals^[16]
• Sensory issues^[16]
• Disinterest in social interaction^[16]
• Autistic characteristics^[16]