is associated with an increased incidence of clubfoot and rocker bottom feet. Also, a significant chance of developing pes planus or pes cavus exists. People with distal 18q- frequently have overlapping toes. Scoliosis and genu varum are also known orthopedic complications in children and adults with distal 18q-. Growth Children and adults with distal 18q- are often small for their age. Many people with distal 18q- have an abnormal response to growth hormone stimulation. Those who have been treated with growth hormone have responded well to the treatment. Microcephaly is also common in people with distal 18q-. Thyroid Hypothyroidism has been reported in some people with distal 18q-. Immunology Several people with distal 18q- have been diagnosed with low IgA levels, resulting in an increased incidence of infections. Psychiatry An increased incidence of psychiatric conditions occurs within the distal 18q- population. In one study, nearly 60% had depressive symptoms, 60% had symptoms of an anxiety disorder, 25% had manic symptoms, and 25% had psychotic symptoms. However, this study included young patients, many of whom were too young to exhibit signs of certain psychiatric conditions. The typical age of onset for many of these conditions appears to be during the teen years. Thus, the results of this study may actually underestimate the true incidence of psychiatric conditions within this population. Outbursts, or anger issues, such as temper tantrums are also common. Cognition and adaptive skills 97% of individuals possess some form of intellectual disability, ranging from moderate to severe cases. The intellectual development of individuals with distal 18q- vary quite widely. In one study of 46 individuals with distal 18q-, IQ ranged from 49 to 113, with most individuals falling in the mild to moderate range of intellectual disability. Some of those with IQ scores on the lower end of the spectrum probably actually had deletions encompassing the TCF4 gene. An increased incidence of autism is seen within the distal 18q- population. In a recent study, 45 of 105 individuals evaluated fell into the "possible" or "very likely" levels of risk for autism. Adaptive skills may also be delayed in people with distal 18q-. Dysmorphology Common facial features include midfacial hypoplasia, short and downward- or upward-slanting palpebral fissures, epicanthic folds, and low-set ears with a prominent antihelix. Genetics Distal 18q- is a deletion of the long arm of chromosome 18. The majority of deletions have breakpoints between 45,405,887 and the tip