Table 1

Clinical and neuroimaging features of affected and asymptomatic carriers of heterozygous truncating and canonical splice site SUFU variants

Patients (n=22)Asymptomatic parents (n=8)
Age, years (mean±SD, range)8.0±4.1 (1–16)41.6±5.5 (32–51)
Sex19 M/3F4 M/4F
Referral diagnosis for genetic test

  • JS

  • Possible JS (some clinical/imaging features)*

  • Isolated COMA

4 (18.2%)
12 (54.5%)
6 (27.3%)		–
Clinical findings
Sitting, months (mean±SD, range)9.7±4.3 (6–24)Reported as normal
Independent walking, months (mean±SD, range)25.7±12.6 (14–72)Reported as normal
Persistent COMA22/22 (100%)0
Macrocephaly†19/22 (86.4%)2/7 (28.6%)
Infantile hypotonia17/22 (77.3%)0
Mild ataxia13/21 (61.9%)1/8 (12.5%)
Speech delay9/20 (45.0%)0
ID (children ≥5 years)7/20 (35.0%)0
Abnormal breathing4/22 (18.2%)0
Education (children ≥6 years)

  • Mainstream school

  • Attendance with support

10/19 (52.6%)
9/19 (47.4%)		8 (100%)
0
Other organ involvement

  • Polydactyly (1)

  • Laryngeal cleft (1)

  • Bicuspid valve insufficiency (1)

0
Neuroimaging ‡
 Superior cerebellar dysplasia22/22 (100%)2/3 (67%)
 Vermis hypoplasia22/22 (100%)2/3 (67%)
 SCP horizontal20/21 (95.2%)2/3 (67%)
 SCP long18/20 (90.0%)2/3 (67%)
 SCP thick19/22 (86.4%)2/3 (67%)
 Vermian split15/18 (83.3%)0/3
 Fastigium displaced13/22 (59.1%)0/3

  • *These patients were reported by referring clinicians/neuroradiologists with variable terminology (JS-like, mild JS, mild MTS, JS spectrum, COMA), as they featured some clinical and imaging features suggestive of JS but not sufficient to reach a definite diagnosis.

  • †Includes parental report of ‘large head’, even if not proven >98 percentile.

  • ‡Some features could not be assessed in all patients due to limited quality of available images.

  • COMA, congenital ocular motor apraxia; JS, Joubert syndrome; MTS, molar tooth sign; SCP, superior cerebellar peduncle.