In a paper published in 2010, 41 of 42 individuals had some type medical problem in the first days of life, the most common being feeding difficulties. Respiratory difficulty and jaundice are also relatively frequent. ENT
Recurrent otitis media is common, and many patients required the placement of PE tubes. Small ear canals are also fairly common, but not as much as in 18q-. Gastrointestinal
The most common gastrointestinal abnormality is chronic constipation, though gastrointestinal reflux was also common. Endocrine
Growth hormone deficiency is present in about 20% of people with tetrasomy 18p. Neurologic
Hypotonia and/or hypertonia are present in nearly all individuals with tetrasomy 18p. Approximately 25% have a seizure disorder. Growth
Short stature is common, with ~50% being at or below the 25th centile and 20% being at or below the 3rd centile. Microcephaly is present in about 40% of patients. Development
All reported cases of tetrasomy 18p have some degree of intellectual disability. Most individuals score in the moderate range of intellectual disability based on standardized testing. Genetics
Tetrasomy 18p is caused by the presence of an additional isochromosome composed of two copies of the p arm of chromosome 18. This extra chromosome is classified as a small supernumerary marker chromosome that forms de novo in a parents egg or sperm or, in rare cases, is directly inherited from a parent carrier of the intact small supernumerary marker chromosome. It has been reported in both the non-mosaic as well as the mosaic state.
Acropachy is a dermopathy associated with Graves disease. It is characterized by soft-tissue swelling of the hands and clubbing of the fingers. Radiographic imaging of affected extremities typically demonstrates periostitis, most commonly the metacarpal bones. The exact cause is unknown, but it is thought to be caused by stimulating auto-antibodies that are implicated in the pathophysiology of Graves thyrotoxicosis. There is no effective treatment for acropachy. Since it is closely associated with Graves disease, it is associated with other manifestations of Graves disease, such as Graves ophthalmopathy and thyroid dermopathy.Hereditary acropachy (also known as "isolated congenital nail clubbing") may be associated with HPGD. See also
Periosteal reaction

References
External links
Radiopaedia.org: Thyroid acropachy