Chromosome 4q deletion syndrome is a chromosomal disorder caused by the loss of a segment of the long arm of chromosome 4. It was first described in 1967 and is associated with symptoms in several organ systems. Patients with chromosome 4q deletion syndrome may have the following symptoms: an unusual skull shape, a short nose with an unusual bridge, low-set ears that may not be well formed, a cleft in the roof of the mouth, a short sternum, poor growth, or Developmental delay, moderate to severe mental retardation, heart defects, abnormal heart rhythm (arrhythmia), defective urinary and reproductive organs (urinary dysfunction), small size, small hands and feet, unusually wide eyes (hypertelorism), Pointed fifth finger and unusual nail and decreased muscle tone (hypotonia) which is common. Some children with this disorder may have a small jaw (micrognathia), which leads to breathing problems, and there may be unusual brain (corpus callosum) findings. Children with small jaws that make breathing difficult may need surgery to lengthen the bones. Medications may be helpful for seizures, reflux, or growth problems.