Table 3

Frequency of the clinical features observed in the series

Number of patientsFrequency (%)
Neurodevelopmental abnormality17/17100
 Intellectual disability17/17100
  Inability to walk11/1765
  Inability to speak14/1782
Muscular hypotonia10/1759
 Autistic behaviour/autism8/1747
 Sleep disturbance6/1735
 Developmental regression5/1729
 Brain imaging abnormality6/1638
  Abnormal myelination2/1613
  Arachnoidal cyst2/1613
  Hypoplasia of the corpus callosum1/166
  Cerebral atrophy1/166
Facial dysmorphism17/17100
 Anteverted nares16/16100
 Broad flat nasal bridge16/16100
 Almond-shaped palpebral fissures16/1794
 Fleshy earlobes15/1694
 Coarse facial features15/1788
 Full cheeks15/1788
 Widely spaced eyes12/1771
 Thick lips12/1771
 Facial hypertrichosis10/1759
Growth abnormality13/1776
 Postnatal growth retardation10/1759
Abnormality of skin pigmentation12/1771
Abnormality of the skeletal system11/1765
 Flat feet7/1741
 Genu valgum3/1620
 Congenital hip dislocation2/1712
 Hip dysplasia2/1712
Abnormality of the eye10/1759
 Abnormality of the visual evoked potentials
 Oculomotor apraxia1/176
 Retinal degeneration1/176
Neonatal features9/1753
 Feeding difficulties3/1718
 Prolonged neonatal jaundice3/1718
Recurrent infections5/1729
Abnormality of the respiratory system4/1724
 Interstitial lung disease1/176
 Chronic lung disease1/176
Cardiac anomaly3/1718
 Aortic insufficiency1/176
 Patent ductus arteriosus1/176
 Abnormal left ventricle morphology1/176
 Hearing loss5/1729
 Clubbing of fingers3/1718
 Umbilical hernia3/1718
 Sleep apnoea syndrome1/176