Tetrasomy X
RARE CHROMOSOMAL DISORDER WITH 4 X CHROMOSOMES
48 xxxx syndrome; Tetrasomy x; 48,xxxx; Tetrasomy-x; XXXX syndrome; 48,XXXX; Quadruple X; 48, XXXX; X tetrasomy; Quadruple X syndrome
Tetrasomy X, also known as 48,XXXX, is a chromosomal disorder in which a female has four, rather than two, copies of the X chromosome. It is associated with intellectual disability of varying severity, characteristic "coarse" facial features, heart defects, and skeletal anomalies such as increased height, clinodactyly (incurved pinky fingers), and radioulnar synostosis (fusion of the long bones in the forearm).