Nevoid basal-cell carcinoma syndrome | |
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Other names | Basal-cell nevus syndrome, Multiple basal-cell carcinoma syndrome, Gorlin syndrome, and Gorlin–Goltz syndrome |
Adult patient with NBCCS | |
Specialty | Medical genetics |
Nevoid basal-cell carcinoma syndrome (NBCCS) is a rare inherited medical condition involving defects within multiple body systems such as the skin, nervous system, eyes, endocrine system, and bones. [1] People with NBCCS are prone to developing various cancers, including a common and usually non-life-threatening form of non-melanoma skin cancer called basal-cell carcinomas (BCCs). [2] Only about 10% of people with the condition do not develop BCCs; the vast majority of patients develop numerous BCCs. [2]
The name Gorlin syndrome refers to the American oral pathologist and human geneticist Robert J. Gorlin (1923–2006). [3] The American dermatologist Robert W. Goltz (1923–2014) [4] was his co-author, which is the basis for the term 'Gorlin-Goltz syndrome'.
First described in 1960 by Gorlin and Goltz, [5] NBCCS is an autosomal dominant condition that can cause unusual facial appearances and a predisposition for basal-cell carcinoma, a type of skin cancer which rarely spreads to other parts of the body. The prevalence is reported to be 1 case per 56,000–164,000 population. Recent work in molecular genetics has shown NBCCS to be caused by mutations in the PTCH (Patched) gene found on chromosome arm 9q [6] or SUFU gene on chromosome arm 10q, [2] though some patients do not have either known mutation. PTCH is important in regulating cell division and growth, thus mutations in this gene can impact tumor growth. [2] Children who inherit the defective gene from either parent will also have the disorder. [7]
Some or all of the following may be seen in someone with Gorlin syndrome: [7]
Mutations in the human homologue of Drosophila patched ( PTCH1 ), a tumor suppressor gene on chromosome 9, were identified as the underlying genetic event in this syndrome. [7] PTCH1 codes for a transmembrane receptor that recognizes the Sonic Hedgehog ligand (SHH) and represses the Hedgehog (Hh) signaling pathway. [7] The Hedgehog signaling pathway, which promotes cell proliferation and differentiation, is involved in more than 50% of cancers. [9] Mutations in PTCH1 could reverse its inhibition of smoothened (SMO) and upregulate the Hedgehog pathway. [7] SUFU codes for the suppressor of fused and inhibits the Hh signaling pathway further downstream by binding to glioma-associated (GLI) transcription factors to prevent translocation to the nucleus. Mutations of SUFU are also correlated with NBCCS. When PTCH1 is mutated, and SMO is no longer inhibited, SUFU consequently becomes activated and GLI can be translocated to the nucleus. SUFU mutations are associated with medulloblastoma, a diagnostic criteria for NBCCS. [7] Up to 70% of people with NBCCS inherit a PTCH1 mutation and around 4% inherit a SUFU mutation. Another 30% obtain a spontaneous, non-inherited mutation of the affected gene resulting in the development of NBCCS. [10]
The most common diagnosing physicians are oral surgeons and dermatologists. However, a NBCCS diagnosis can also be made by geneticists, dentists, orthodontists, primary care physicians, Mohs surgeons, and oncologists. Though not inclusive, this list includes most of the diagnosing healthcare providers. [11]
Diagnosis of NBCCS is made by having two major criteria or one major and two minor criteria. [12]
The major criteria consist of the following:
The minor criteria include the following:
The first presentation of NBCCS is often odontogenic keratocysts that begin to occur, on average, around 13 years of age. Other common initial presentations include multiple BCCs before the age of 20 and medulloblastoma occurring around the age of two. [2]
People with NBCCS need education about the syndrome, and may need counseling and support, as coping with the multiple BCCs and multiple surgeries is often difficult. They should reduce UV light exposure, to minimize the risk of BCCs. They should also be advised that receiving Radiation therapy for their skin cancers may be contraindicated. They should look for symptoms referable to other potentially involved systems: the CNS, the genitourinary system, the cardiovascular system, and dentition. [8]
Genetic counseling is advised for prospective parents, since one parent with NBCCS causes a 50% chance that their child will also be affected. [8] Genetic testing is a sufficient way to confirm the diagnosis when there is suspicion but a lack of clinical diagnostic criteria. It is also beneficial for prenatal testing when there is a know family history of NBCCS. [2]
Treatment is usually multidisciplinary, supportive treatment, that is, treatment to reduce any symptoms rather than to cure the condition. [2] Having a multidisciplinary medical team is important for managing the symptoms, preventing new tumors, and providing support. Many people with NBCCS see a number of physicians and medical professionals on a regular basis including a primary care physician, dermatologist, cardiologist, oral surgeon, therapist, plastic surgeon, neurologist, and gynecologist. Building a medical care team provides patients with the tools for managing their condition. [13]
Proper sun protection is extremely important for patients with suspected and confirmed diagnoses of NBCCS. Patients and their families should monitor for signs of NBCCS including developmental delays, abnormal skin lesions, and odontogenic keratocysts in between visits with their multidisciplinary team. [7]
NBCCS has an incidence of 1 in 50,000 to 150,000 with higher incidence in Australia. One aspect of NBCCS is that basal-cell carcinomas will occur on areas of the body which are not generally exposed to sunlight, such as the palms and soles of the feet and lesions may develop at the base of palmar and plantar pits. One of the prime features of NBCCS is development of multiple BCCs at an early age, often in the teen years. Each person who has this syndrome is affected to a different degree, some having many more characteristics of the condition than others. [2]
The Gorlin Syndrome Alliance (GSA) is an organization designed to raise awareness and connect those with NBCCS or those who know someone with NBCCS. Within the entirety of the GSA community, there is a great amount of support, education, and drive for furthering research. [15]
Basal-cell carcinoma (BCC), also known as basal-cell cancer, basalioma or rodent ulcer, is the most common type of skin cancer. It often appears as a painless raised area of skin, which may be shiny with small blood vessels running over it. It may also present as a raised area with ulceration. Basal-cell cancer grows slowly and can damage the tissue around it, but it is unlikely to spread to distant areas or result in death.
Gardner's syndrome is a subtype of familial adenomatous polyposis (FAP). Gardner syndrome is an autosomal dominant form of polyposis characterized by the presence of multiple polyps in the colon together with tumors outside the colon. The extracolonic tumors may include osteomas of the skull, thyroid cancer, epidermoid cysts, fibromas, as well as the occurrence of desmoid tumors in approximately 15% of affected individuals.
Birt–Hogg–Dubé syndrome (BHD), also Hornstein–Birt–Hogg–Dubé syndrome, Hornstein–Knickenberg syndrome, and fibrofolliculomas with trichodiscomas and acrochordons is a human, adult onset, autosomal dominant genetic disorder caused by a mutation in the folliculin (FLCN) gene. It can cause susceptibility to kidney cancer, renal and pulmonary cysts, and noncancerous tumors of the hair follicles, called fibrofolliculomas. The symptoms seen in each family are unique, and can include any combination of the three symptoms. Fibrofolliculomas are the most common manifestation, found on the face and upper trunk in over 80% of people with BHD over the age of 40. Pulmonary cysts are equally common (84%) and 24% of people with BHD eventually experience a collapsed lung. Kidney tumors, both cancerous and benign, occur in 14–34% of people with BHD; the associated kidney cancers are often rare hybrid tumors.
A bifid rib is a congenital abnormality of the rib cage and associated muscles and nerves which occurs in about 1.2% of humans. Bifid ribs occur in up to 8.4% of Samoans. The sternal end of the rib is cleaved into two. It is usually unilateral.
Zinc finger protein GLI3 is a protein that in humans is encoded by the GLI3 gene.
The Hedgehog signaling pathway is a signaling pathway that transmits information to embryonic cells required for proper cell differentiation. Different parts of the embryo have different concentrations of hedgehog signaling proteins. The pathway also has roles in the adult. Diseases associated with the malfunction of this pathway include cancer.
An odontogenic keratocyst is a rare and benign but locally aggressive developmental cyst. It most often affects the posterior mandible and most commonly presents in the third decade of life. Odontogenic keratocysts make up around 19% of jaw cysts.. Despite its more common appearance in the bone region, it can affect soft tissue.
Protein patched homolog 1 is a protein that is the member of the patched family and in humans is encoded by the PTCH1 gene.
Focal dermal hypoplasia is a form of ectodermal dysplasia. It is a multisystem disorder characterized primarily by skin manifestations to the atrophic and hypoplastic areas of skin which are present at birth. These defects manifest as yellow-pink bumps on the skin and pigmentation changes. The disorder is also associated with shortness of stature and some evidence suggests that it can cause epilepsy.
Patched (Ptc) is a conserved 12-pass transmembrane protein receptor that plays an obligate negative regulatory role in the Hedgehog signaling pathway in insects and vertebrates. Patched is an essential gene in embryogenesis for proper segmentation in the fly embryo, mutations in which may be embryonic lethal. Patched functions as the receptor for the Hedgehog protein and controls its spatial distribution, in part via endocytosis of bound Hedgehog protein, which is then targeted for lysosomal degradation.
A keratocyst is a type of cutaneous cyst. They appear similar to epidermoid cysts; however, are not limited to a specified location on the body. Keratocyst are most often reported in persons with nevoid basal cell carcinoma syndrome.
Odontogenic cyst are a group of jaw cysts that are formed from tissues involved in odontogenesis. Odontogenic cysts are closed sacs, and have a distinct membrane derived from rests of odontogenic epithelium. It may contain air, fluids, or semi-solid material. Intra-bony cysts are most common in the jaws, because the mandible and maxilla are the only bones with epithelial components. That odontogenic epithelium is critical in normal tooth development. However, epithelial rests may be the origin for the cyst lining later. Not all oral cysts are odontogenic cysts. For example, mucous cyst of the oral mucosa and nasolabial duct cyst are not of odontogenic origin.
The ovarian fibroma, also fibroma, is a benign sex cord-stromal tumour.
A hereditary cancer syndrome is a genetic disorder in which inherited genetic mutations in one or more genes predispose the affected individuals to the development of cancer and may also cause early onset of these cancers. Hereditary cancer syndromes often show not only a high lifetime risk of developing cancer, but also the development of multiple independent primary tumors.
Sonidegib (INN), sold under the brand name Odomzo, is a medication used to treat cancer.
Patched 2 is a protein that in humans is encoded by the PTCH2 gene.
Hedgehog pathway inhibitors, also sometimes called hedgehog inhibitors, are small molecules that inhibit the activity of a component of the Hedgehog signaling pathway. Due to the role of aberrant Hedgehog signaling in tumor progression and cancer stem cell maintenance across cancer types, inhibition of the Hedgehog signaling pathway can be a useful strategy for restricting tumor growth and for preventing the recurrence of the disease post-surgery, post-radiotherapy, or post-chemotherapy. Thus, Hedgehog pathway inhibitors are an important class of anti-cancer drugs. At least three Hedgehog pathway inhibitors have been approved by the Food and Drug Administration (FDA) for cancer treatment. These include vismodegib and sonidegib, both inhibitors of Smoothened (SMO), which are being used for the treatment of basal cell carcinoma. Arsenic trioxide, an inhibitor of GLI transcription factors, is being used for the treatment of acute promyelocytic leukemia. In addition, multiple other Hedgehog pathway inhibitors are in different phases of clinical trials.
CYLD cutaneous syndrome (CCS) encompasses three rare inherited cutaneous adnexal tumor syndromes: multiple familial trichoepithelioma (MFT1), Brooke–Spiegler syndrome (BSS), and familial cylindromatosis (FC). Cutaneous adnexal tumors are a large group of skin tumors that consist of tissues that have differentiated towards one of the four primary adnexal structures found in normal skin: hair follicles, sebaceous sweat glands, apocrine sweat glands, and eccrine sweat glands. CCS tumors are hair follicle tumors.
Curry–Jones syndrome is a rare genetic disorder characterized by congenital brain, osseous, cutaneous, ocular, and intestinal anomalies.