CDKL1 and Disproportionate tall stature: Her brother, patient P5 (Figure 1B), also carries the CDKL1 c.617C>T variant and presented with scoliosis, positive thumb sign, greater than 90° extension of the fifth digit, reduced upper segment/lower segment ratio, increased arm/height ratio (dolichostenomelia), and dural ectasia at the age of 23 years and at his most recent clinical examination at the age of 34 years.