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Oral-facial-digital syndrome type 1
OFD1 is a rare genetic disorder that can lead to a range of developmental differences, including distinctive facial features, clefts in the tongue, and structural changes in the digits. It predominantly affects females, with severe outcomes typically observed in males.
Overview
Oral-facial-digital syndrome type 1 (OFD1) is a rare inherited condition characterised by a combination of malformations affecting the mouth, face, and digits (fingers and toes). It is one of several types of oral-facial-digital syndromes, each with distinct genetic causes. OFD1 is also known as Papillon-Léage and Psaume syndrome and is estimated to affect around 1 in 50,000 individuals [PMID:12883395].
The condition typically presents with a wide range of features, varying in severity even within the same family. While females are most commonly affected, severe forms are generally observed in males, often leading to early pregnancy loss. The presence and extent of these features can vary significantly among affected individuals.
Symptoms & clinical features
Individuals with OFD1 may present with a variety of features affecting the oral cavity, face, and digits. Oral features can include a cleft or notched tongue, additional oral frenula (small folds of tissue connecting the lip or tongue to the gum), and cleft lip or palate. Dental anomalies are common, such as missing teeth, extra teeth, or abnormally shaped teeth.
Facial characteristics may involve widely spaced eyes (hypertelorism), a broad nasal bridge, and small jaw (micrognathia). Digital abnormalities often include shortened, broadened, or bent fingers and toes (brachydactyly, clinodactyly), as well as fusion of fingers or toes (syndactyly) [PMID:10629215].
Beyond these primary features, OFD1 can also affect other body systems. Some individuals may have learning difficulties, and neurological problems, such as hydrocephalus (fluid accumulation in the brain), can occur. Kidney involvement, including polycystic kidney disease, is another possible feature that may develop later in life. Hair and skin changes, such as dry hair and milia (small cysts on the skin), have also been reported.
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Affected organs
OFD1 primarily impacts the development of structures derived from the first branchial arch during embryonic development, leading to its characteristic oral, facial, and digital manifestations. This includes the tongue, palate, jaw, and the bones of the hands and feet.
Beyond these areas, other organ systems can be affected. The brain may be impacted, leading to structural anomalies and sometimes developmental differences. The kidneys are also a key organ system to consider, as polycystic kidney disease can develop, which may require ongoing monitoring and management. Hair and skin can also show distinctive features.
Risks & severity
The severity of OFD1 varies considerably among affected individuals. Some may have relatively mild features, while others experience more significant health challenges. The condition shows a broad clinical spectrum, meaning no two people will have exactly the same set of symptoms or the same degree of severity.
For affected females, risks typically relate to the potential for developmental delays, kidney problems, and ongoing management of oral and digital anomalies. In males, the condition is usually much more severe due to its X-linked dominant inheritance pattern, often resulting in early pregnancy loss or severe multi-systemic disease shortly after birth. This difference in severity between sexes is a hallmark of the condition [PMID:20301389].
Genetic causes
Oral-facial-digital syndrome type 1 is caused by pathogenic variants in the OFD1 gene. This gene provides instructions for making a protein involved in the function and structure of cilia and centrosomes. Cilia are small, hair-like structures on the surface of cells that play a crucial role in cell signalling and development.
The OFD1 protein is important for the proper formation and function of these cellular structures, which are vital for the normal development of many tissues and organs, particularly during embryonic growth. When the OFD1 gene carries a pathogenic variant, the protein's function is impaired, disrupting normal ciliary and centrosomal activity. This disruption leads to the wide range of developmental abnormalities observed in OFD1, affecting the formation of the face, mouth, digits, and sometimes other organs like the kidneys and brain.
- OFD1 OFD1 centriole and centriolar satellite protein
Inheritance pattern
Oral-facial-digital syndrome type 1 follows an X-linked dominant inheritance pattern. This means the OFD1 gene is located on the X chromosome, and only one copy of the pathogenic variant on an X chromosome is sufficient to cause the condition.
Females have two X chromosomes, so if one X chromosome carries the pathogenic variant, they will be affected. However, due to X-inactivation (where one of the X chromosomes is randomly 'switched off' in each cell), females often experience milder and more variable symptoms. Males have only one X chromosome and one Y chromosome. If a male inherits an X chromosome with the pathogenic variant, they will be severely affected, often leading to early pregnancy loss. Affected females have a 50% chance of passing the condition to each of their children, regardless of sex. Affected males typically do not survive to reproduce.
X-linked dominant: all daughters of an affected father inherit the altered X and are affected. Sons receive the father's Y and are unaffected.
Diagnosis & testing
A diagnosis of OFD1 is typically suspected based on characteristic clinical features, such as specific oral, facial, and digital abnormalities. Further investigation might involve imaging studies to look for internal anomalies, such as brain or kidney cysts.
Confirmation of the diagnosis is achieved through genetic testing, which looks for pathogenic variants in the OFD1 gene. In the UK, genetic testing for OFD1 falls under the NHS Genomic Medicine Service (GMS). Referral to a clinical genetics service is generally required to access this testing, often utilising an R-code such as R253 Craniosynostosis and craniofacial syndromes for initial assessment, though the specific R-code may vary depending on the primary presenting features. Genetic counsellors can provide support and information about testing options and inheritance patterns.
Management & lifestyle
Management for individuals with OFD1 is multidisciplinary and tailored to the specific symptoms present. It aims to address the various developmental and health concerns as they arise. For oral and facial features, surgical correction of cleft lip or palate may be necessary, and dental care is often ongoing due to tooth abnormalities.
Orthopaedic interventions might be considered for significant digital anomalies. If kidney involvement, such as polycystic kidney disease, is present, regular monitoring by a nephrologist (kidney specialist) is important to manage kidney function. Neurological concerns, including developmental delays or hydrocephalus, would be managed by paediatric neurologists or other specialists as appropriate.
Speech and language therapy, occupational therapy, and educational support can be beneficial for developmental challenges. A clinical genetics team will help coordinate care and provide ongoing genetic counselling. Regular follow-up with various specialists ensures comprehensive care and early intervention for new symptoms.
UK care pathway
In the UK, individuals suspected of having OFD1 would typically be referred to a clinical genetics service. This service provides expert assessment, diagnostic genetic testing through the NHS Genomic Medicine Service, and genetic counselling. The diagnostic pathway often involves specific R-codes, such as those related to craniofacial conditions (e.g., R253) or broader syndromic intellectual disability, depending on the predominant features.
Genetic counsellors within these services play a vital role, explaining the inheritance pattern, implications for family members, and helping to navigate the complex care pathway. They also provide emotional support and connect families with relevant patient support groups and resources.
Frequently asked questions
What is the life expectancy for someone with OFD1?
Life expectancy for individuals with OFD1 can vary. Females generally have a normal lifespan, though it can be influenced by the severity of kidney disease or neurological complications. Males often experience very severe forms of the condition, frequently leading to early pregnancy loss or severe complications shortly after birth.
Can OFD1 be detected during pregnancy?
In some cases, severe manifestations of OFD1, such as polycystic kidneys or significant brain abnormalities, might be detected during prenatal ultrasound scans. If there's a family history of OFD1, prenatal genetic testing can be discussed with a genetic counsellor to determine if the pathogenic variant has been passed on.
Will my children inherit OFD1 if I have it?
OFD1 is inherited in an X-linked dominant manner. If you are an affected female, there is a 50% chance for each child, regardless of sex, to inherit the pathogenic variant. Affected males are rarely seen due to the severity of the condition, and typically do not pass on the condition.
What kind of doctors will my child need to see if they have OFD1?
A child with OFD1 typically requires a team of specialists. This may include a clinical geneticist, paediatrician, craniofacial surgeon, dentist, orthodontist, nephrologist (kidney specialist), neurologist, and therapists such as speech and language therapists, and occupational therapists. This multidisciplinary approach ensures comprehensive care for all aspects of the condition.
Are there any support groups for OFD1 in the UK?
While there may not be a specific UK-based support group solely for OFD1 due to its rarity, organisations like Unique (Rare Chromosome and Gene Disorder Support Group) or national rare disease charities may offer support and connect families with similar experiences. Your genetic counsellor can also provide information on available resources.
References
- Ko YW, Ko JY, Ro YS. Oral-Facial-Digital Syndrome Type 1: A Case Report and Review. Annals of dermatology. 2022. PMID: 35450320
- Macca M, Franco B. The molecular basis of oral-facial-digital syndrome, type 1. American journal of medical genetics. Part C, Seminars in medical genetics. 2009. PMID: 19876934
- Faily S, Perveen R, Chandler K. Oral-Facial-Digital Syndrome Type 1: Further Clinical and Molecular Delineation in 2 New Families. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association. 2020. PMID: 32064904
- Azukizawa T, Yamamoto M, Narumiya S. Oral-facial-digital syndrome type 1 with hypothalamic hamartoma and Dandy-Walker malformation. Pediatric neurology. 2013. PMID: 23498571
- Mihci E, Tacoy S, Ozbilim G. Oral-facial digital syndrome type 1. Indian pediatrics. 2007. PMID: 18057484
- Chen CP. Meckel syndrome: genetics, perinatal findings, and differential diagnosis. Taiwanese journal of obstetrics & gynecology. 2007. PMID: 17389183
- Happle R. X-chromosome inactivation: role in skin disease expression. Acta paediatrica (Oslo, Norway : 1992). Supplement. 2006. PMID: 16720460
- Tagliani MM, Gomide MR, Carrara CF. Oral-facial-digital syndrome type 1: oral features in 12 patients submitted to clinical and radiographic examination. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association. 2010. PMID: 20210637