Clinical Characteristics

The clinical features of MRT68 include:

Neurologic abnormalities

  • Intellectual disability
  • Epilepsy (in some patients)
  • Developmental delay that can be generalized (affecting all areas of development, including motor, speech, cognitive, and social) or limited to specific areas of development, such as:
  • Cognitive delay
  • Speech delay
  • Delayed walking
  • Spasticity of the lower limbs (in some patients)
  • Weak muscle tone (in some patients)
  • Hearing loss (found in 1 patient)
  • Structural brain abnormalities found on MRI imaging (found in some patients):
  • Atrophy of the cerebellum, the structure that is responsible for balance and coordinating movements
  • Abnormalities in the white matter (the nerves that link parts of the brain to each other and to the spinal cord)

Facial dysmorphisms (variable, mild; found in some patients)

  • Deep-set eyes
  • Epicanthus
  • Smooth philtrum (philtrum is the vertical groove between the nose and the upper lip)
  • Pointed chin
  • Unibrow 
  • Narrow eyes
  • Broad eyebrows
  • Broad nasal bridge 

Musculoskeletal abnormalities (found in some patients)

  • Flatfoot
  • Muscle weakness
  • Joint hypermobility (found in 1 patient)
  • Persistent fetal fingertip pads (found in 1 patient)
  • Bending of the fifth finger (found in 1 patient)

Other (found in some patients)

  • Low birth weight
  • Poor growth
  • Microcephaly (abnormally small head)
  • Breath-holding spells (found in 1 patient)
  • Increased number of platelets