Orofaciodigital Syndrome, Type VI

Clinical Characteristics
Ocular Features: 

Hypertelorism and epicanthal folds have been described.  Some patients have nystagmus and strabismus. Ocular apraxia and difficulties in smooth visual pursuit may be present.   

Systemic Features: 

Polydactyly of the hands is a common feature.  The central metacarpal is often Y-shaped leading to ‘central polydactyly’.  The large toes may be bifid.  Cognitive deficits are common and some patients have been considered mentally retarded.  The ears are low-set and rotated posteriorly.  Some patients have a conductive hearing loss.  Oral anomalies may include a lobed tongue, lingual and sublingual hemartomas, micrognathia, clefting, and multiple buccoalveolar frenula.  Congenital heart anomalies, micropenis, and cryptorchidism have been reported.  Tachypnea and tachycardia have been noted.  Some patients have some degree of skeletal dysplasia and many individuals are short in stature.

The presence of cerebellar abnormalities such as hypoplasia (including absence) of the vermis may help to distinguish type VI from other forms of OFDS.  Hypothalamic dysfunction may be responsible for poor temperature regulation (hyperthermia). The ‘molar tooth sign’ seen on brain MRIs in Joubert syndrome (213300) is also present in OFDS VI. 


This is a rare condition with limited family information.  Parents in one family were consanguineous, and multiple affected sibs in other families suggest this may be an autosomal recessive condition.  Homozygous mutations in TMEM216 have been found. Other patients have mutations in C5orf42.

Many of the clinical features in OFDS VI are also found among individuals with Joubert (213300) and Meckel (249000) syndromes that also sometimes have mutations in the TMEM216 and C5orf42 genes.  Some consider all of these conditions to be members of a group of overlapping disorders called ciliopathies or ciliary dyskinesias.   

Autosomal recessive
Treatment Options: 

No specific treatment is available for this syndrome but individual signs and symptoms may need treatment.

Article Title: 

C5orf42 is the major gene responsible for OFD syndrome type VI

Lopez E, Thauvin-Robinet C, Reversade B, Khartoufi NE, Devisme L, Holder M, Ansart-Franquet H, Avila M, Lacombe D, Kleinfinger P, Kaori I, Takanashi JI, Le Merrer M, Martinovic J, No?'l C, Shboul M, Ho L, G?oven Y, Razavi F, Burglen L, Gigot N, Darmency-Stamboul V, Thevenon J, Aral B, Kayserili H, Huet F, Lyonnet S, Le Caignec C, Franco B, Rivi?(r)re JB, Faivre L, Atti?(c)-Bitach T. C5orf42 is the major gene responsible for OFD syndrome type VI. Hum Genet. 2013 Nov 1. [Epub ahead of print].

PubMed ID: 

Mutations in TMEM216 perturb ciliogenesis and cause Joubert, Meckel and related syndromes

Valente EM, Logan CV, Mougou-Zerelli S, Lee JH, Silhavy JL, Brancati F, Iannicelli M, Travaglini L, Romani S, Illi B, Adams M, Szymanska K, Mazzotta A, Lee JE, Tolentino JC, Swistun D, Salpietro CD, Fede C, Gabriel S, Russ C, Cibulskis K, Sougnez C, Hildebrandt F, Otto EA, Held S, Diplas BH, Davis EE, Mikula M, Strom CM, Ben-Zeev B, Lev D, Sagie TL, Michelson M, Yaron Y, Krause A, Boltshauser E, Elkhartoufi N, Roume J, Shalev S, Munnich A, Saunier S, Inglehearn C, Saad A, Alkindy A, Thomas S, Vekemans M, Dallapiccola B, Katsanis N, Johnson CA, Atti?(c)-Bitach T, Gleeson JG. Mutations in TMEM216 perturb ciliogenesis and cause Joubert, Meckel and related syndromes. Nat Genet. 2010 Jul;42(7):619-25.

PubMed ID: 
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