Trisomy 18 Syndrome

**Definition:** A chromosome disorder associated with TRISOMY of all or part of CHROMOSOME 18. Clinical manifestations include INTRAUTERINE GROWTH RETARDATION; CLEFT PALATE; CONGENITAL HEART DEFECTS; MICROCEPHALY; MICROGNATHIA and clenched fists with overlapping fingers. Most affected fetuses do not survive to birth. Those who survive through their first year often have severe INTELLECTUAL DISABILITY.

**Tree numbers:** - C14.240.400.975 - C14.280.400.975 - C16.131.077.929 - C16.131.240.400.968 - C16.131.260.932 - C16.320.180.932