MedGen

Classic Joubert syndrome (JS) is characterized by three primary findings: A distinctive cerebellar and brain stem malformation called the molar tooth sign (MTS). Hypotonia. Developmental delays. Often these findings are accompanied by episodic tachypnea or apnea and/or atypical eye movements. In general, the breathing abnormalities improve with age, truncal ataxia develops over time, and acquisition of gross motor milestones is delayed. Cognitive abilities are variable, ranging from severe intellectual disability to normal. Additional findings can include retinal dystrophy, renal disease, ocular colobomas, occipital encephalocele, hepatic fibrosis, polydactyly, oral hamartomas, and endocrine abnormalities. Both intra- and interfamilial variation are seen. [from GeneReviews]

Simpson-Golabi-Behmel syndrome type 2 (SGBS2) is an X-linked recessive disorder in which affected males have severely impaired intellectual development, ciliary dyskinesia, and macrocephaly (summary by Budny et al., 2006). For a general phenotypic description and a discussion of genetic heterogeneity of Simpson-Golabi-Behmel syndrome, see 312870. [from OMIM]

Oral-facial-digital syndrome type I (OFD1) is usually male lethal during gestation and predominantly affects females. OFD1 is characterized by the following features: Oral (lobulated tongue, tongue nodules, cleft of the hard or soft palate, accessory gingival frenulae, hypodontia, and other dental abnormalities). Facial (widely spaced eyes or telecanthus, hypoplasia of the alae nasi, median cleft or pseudocleft upper lip, micrognathia). Digital (brachydactyly, syndactyly, clinodactyly of the fifth finger; duplicated hallux [great toe]). Kidney (polycystic kidney disease). Brain (e.g., intracerebral cysts, agenesis of the corpus callosum, cerebellar agenesis with or without Dandy-Walker malformation). Intellectual disability (in ~50% of individuals). [from GeneReviews]

Any retinitis pigmentosa in which the cause of the disease is a mutation in the OFD1 gene. [from MONDO]