Table I.
Clinical features of each of the partially overlapping conditions within the Joubert syndrome and related disorders spectrum
| Clinical feature | JS | CORS | LCA | SLS | MKS | DKA | BBS | COACH | OFD6 | Cogan |
|---|---|---|---|---|---|---|---|---|---|---|
| Hypotonia | + | + | +/− | +/− | N/A | +/− | +/− | +/− | +/− | + |
| Intellectually impaired | +a | + | +/− | +/− | N/A | +/− | + | +/− | + | +/− |
| Hyperpnoea/apnoea | + | +/− | +/− | +/− | N/A | +/− | +/− | +/− | +/− | – |
| Oculomotor apraxia | + | + | +/− | − | N/A | − | − | − | − | + |
| Coloboma | − | − | − | − | +/− | − | − | + | − | − |
| Retinal dystrophy | +/− | + | + | + | − | + | + | − | − | − |
| Tongue hamartoma | − | − | − | − | − | − | − | − | + | − |
| Oral frenula | − | − | − | − | − | − | − | − | + | − |
| Orofacial clefting | − | − | − | − | +/− | − | − | − | + | − |
| Cystic renal dystrophy | − | + | − | − | + | + | + | − | − | − |
| Nephronophthisis | − | + | − | + | − | + | +/− | − | − | +/− |
| Hepatic fibrosis | − | − | − | − | − | − | +/− | + | − | − |
| Polymicrogyria | +/− | − | − | − | − | − | − | − | − | − |
| Encephalocele | − | − | − | − | + | − | − | − | − | − |
| MTS | + | + | +/− | +/− | +/− | +/− | +/− | +/− | +/− | +/− |
| Polydactyly | − | − | − | − | + | − | + | − | + | − |
| Obesity | − | − | − | − | N/A | − | + | − | − | − |
| Inheritance | ARb | AR | ARc | AR | AR | AR | AR | AR | AR | AR |
Most individuals are intellectually impaired but occasionally normal intelligence is seen with mild forms of disease.
Most cases of Joubert syndrome (JS) are inherited in a recessive fashion except for the OFD1, which can be X-linked.
Most cases of Leber congenital amaurosis (LCA) are inherited in a recessive fashion except forthe IMPDH1 gene mutation, inherited dominantly, and the CRX gene, inherited in an X-linked fashion. +, presence or −, absence of clinical sign and symptoms; +/−, a feature that can be present or absent within the various ciliopathies. CORS, cerebellar–ocular–renal syndrome; SLS, Senior–Løken syndrome; MKS, Meckel–Gruber syndrome; DKA, Dekaban–Arima syndrome; BBS, Bardet–Biedl syndrome; COACH, cerebellar vermis hypo-/aplasia, oligophrenia, congenital ataxia, ocular coloboma, and hepatic fibrosis; OFD, orofacial digital syndrome; Cogan, Cogan-type congenital oculomotor apraxia; MTS, molartooth sign; AR, autosomal recessive; N/A, not applicable.