Novel PTCH1 Mutation Causes Gorlin-Goltz Syndrome.

OBJECTIVE: To analyse the aetiology and pathogenesis of Gorlin-Goltz syndrome (GS; also known as nevoid basal cell carcinoma syndrome [NBCCS] or basal cell nevus syndrome [BCNS]) in a Chinese family. METHODS: Whole-exome sequencing (WES) was performed on genomic DNA samples from the subjects in a family, followed by the investigation of pathogenesis via bioinformatic approaches and conformational analysis. RESULTS: A novel heterozygous non-frameshift deletion patched 1 (PTCH1) [NM_000264: c.3512_3526del (p.1171_1176del)] was identified by WES and further validated by Sanger sequencing. Bioinformatic and conformational analysis showed that the mutation caused altered PTCH1 protein structure, which may be related to functional abnormalities. CONCLUSION: This study expands the mutation spectrum of PTCH1 in GS and facilitates the early diagnosis and screening of GS. PTCH1 [c.3512_3526del (p.1171_1176del)] may cause structural abnormalities and functional disabilities, leading to GS in families.

Gorlin-Like Phenotype in a Young Girl With a De Novo PTCH2 Variant Mutation of Uncertain Significance.

ABSTRACT: Gorlin syndrome, also known as basal cell nevus syndrome, is an autosomal dominant genetic disorder that predisposes humans to tumors. In most cases, this syndrome results from inactivating mutations in the patched homologue 1 gene. Basal cell carcinomas are one of the main characteristics of this syndrome and serve as a major diagnostic criterion. Gorlin syndrome shows a variable phenotype, and recently, other less common mutations in the suppressor of fused homologue or patched homologue 2 genes have been documented in individuals with this syndrome. We present the case of a patient with early-onset basal cell carcinomas and a mild Gorlin syndrome phenotype, attributed to a de novo patched homologue 2 variant of uncertain significance, which has not been previously reported in the literature.

Medulloblastoma and other neoplasms in patients with heterozygous germline SUFU variants: A scoping review.

In 2002, heterozygous suppressor of fused variants (SUFU+/-) in the germline were described to have a tumor suppressor role in the development of pediatric medulloblastoma (MB). Other neoplasms associated with pathologic germline SUFU+/- variants have also been described among patients with basal cell nevus syndrome (BCNS; BCNS is also known as Gorlin syndrome, nevoid basal cell carcinoma [BCC] syndrome or Gorlin-Goltz syndrome; OMIM 109400), an autosomal-dominant cancer predisposition syndrome. The phenotype of patients with germline SUFU+/- variants is very poorly characterized due to a paucity of large studies with long-term follow-up. As such, there is a clinical need to better characterize the spectrum of neoplasms among patients with germline SUFU+/- variants so that clinicians can provide accurate counseling and optimize tumor surveillance strategies. The objective of this study is to perform a scoping review to map the evidence on the rate of medulloblastoma and to describe the spectrum of other neoplasms among patients with germline SUFU+/- variants. A review of all published literature in PubMed (MEDLINE), EMBASE, Cochrane, and Web of Science were searched from the beginning of each respective database until October 9, 2021. Studies of pediatric and adult patients with a confirmed germline SUFU+/- variant who were evaluated for the presence of any neoplasm (benign or malignant) were included. There were 176 patients (N = 30 studies) identified with a confirmed germline SUFU+/- variant who met inclusion criteria. Data were extracted from two cohort studies, two case-control studies, 18 case series, and eight case reports. The median age at diagnosis of a germline SUFU+/- variant was 4.5 years where 44.4% identified as female and 13.4% of variants were de novo. There were 34 different neoplasms (benign and malignant) documented among patients with confirmed germline SUFU+/- variants, and the most common were medulloblastoma (N = 59 patients), BCC (N = 21 patients), and meningioma (N = 19 patients). The median age at medulloblastoma diagnosis was 1.42 years (range 0.083-3; interquartile range 1.2). When data were available for these three most frequent neoplasms (N = 95 patients), 31 patients (32.6%) had neither MB, BCC nor meningioma; 51 patients (53.7%) had one of medulloblastoma or BCC or meningioma; eight patients (8.4%) had two of medulloblastoma or BCC or meningioma, and five patients (5.3%) had medulloblastoma and BCC and meningioma. This is the first study to synthesize the data on the frequency and spectrum of neoplasms specifically among patients with a confirmed germline SUFU+/- variant. This scoping review is a necessary step forward in optimizing evidence-based tumor surveillance strategies for medulloblastoma and estimating the risk of other neoplasms that could impact patient outcomes.

Acquisition of Drug Resistance in Basal Cell Nevus Syndrome Tumors through Basal to Squamous Cell Carcinoma Transition.

Although basal cell carcinomas arise from ectopic Hedgehog pathway activation and can be treated with pathway inhibitors, sporadic basal cell carcinomas display high resistance rates, whereas tumors arising in patients with Gorlin syndrome with germline Patched (PTCH1) alterations are uniformly suppressed by inhibitor therapy. In rare cases, patients with Gorlin syndrome on long-term inhibitor therapy will develop individual resistant tumor clones that rapidly progress, but the basis of this resistance remains unstudied. In this study, we report a case of an SMO inhibitor-resistant tumor arising in a patient with Gorlin syndrome on suppressive SMO inhibitor for nearly a decade. Using a combination of multiomics and spatial transcriptomics, we define the tumor populations at the cellular and tissue level to conclude that Gorlin tumors can develop resistance to SMO inhibitors through the previously described basal to squamous cell carcinoma transition. Intriguingly, through spatial whole-exome genomic analysis, we nominate PCYT2, ETNK1, and the phosphatidylethanolamine biosynthetic pathway as genetic suppressors of basal to squamous cell carcinoma transition resistance. These observations provide a general framework for studying tumor evolution and provide important clinical insight into mechanisms of resistance to SMO inhibitors for not only Gorlin syndrome but also sporadic basal cell carcinomas.

Exploring the Changing Diagnostic Criteria of Gorlin-Goltz Syndrome: A Case Report.

Gorlin-Goltz syndrome, also known as Gorlin syndrome, basal cell nevus syndrome, and nevoid basal cell carcinoma syndrome, is an autosomal dominant genetic disorder. Its hallmark is an early onset of basal cell carcinoma. Additionally, the syndrome is characterized by a spectrum of distinct clinical attributes encompassing oral, skeletal, ophthalmic, neurological, and developmental aberrations. This condition arises due to anomalies in the Hedgehog signaling pathway, leading to constant pathway activity and uncontrolled growth of tumor cells. Early identification of the disorder through available diagnostic methods and clinical and radiological findings is crucial for accurate diagnosis, which subsequently leads to the formulation of an effective treatment regimen. The purpose of this case report is to discuss the role of a dentist in early detection based on various author-prescribed criteria and the need for a multidisciplinary approach to the treatment of patients with this syndrome.

Bilateral ovarian fibromas as the sole manifestation of Gorlin syndrome in a 22-year-old woman: a case report and literature review.

BACKGROUND: Nevoid basal cell carcinoma syndrome (NBCCS, Gorlin syndrome) is a rare autosomal dominantly inherited disorder that is characterized by multisystem disorder such as basal cell carcinomas, keratocystic odontogenic tumors and skeletal abnormalities. Bilateral and/or unilateral ovarian fibromas have been reported in individuals diagnosed with NBCCS. CASE PRESENTATION: A 22-year-old female, presented with low back pain, and was found to have bilateral giant adnexal masses on pelvic ultrasonography, which had been suspected to be malignant ovarian tumors. Positron emission tomography/computed tomography showed multiple intracranial calcification and skeletal abnormalities. The left adnexa and right ovarian tumor were resected with laparotomy, and pathology revealed bilateral ovarian fibromas with marked calcification. We recommended the patient to receive genetic testing and dermatological examination. No skin lesion was detected. Germline testing identified pathogenic heterozygous mutation in PTCH1 (Patched1). CONCLUSIONS: The possibility of NBCCS needs to be considered in patients with ovarian fibromas diagnosed in an early age. Skin lesions are not necessary for the diagnosis of NBCCS. Ovarian fibromas are managed with surgical excision with an attempt at preserving ovarian function. Follow-up regime and counseling on options for future fertility should be offered to patients.

Establishment of induced pluripotent stem cells derived from patients and healthy siblings of a nevoid basal cell carcinoma syndrome family.

It is known that a nevoid basal cell carcinoma syndrome (NBCCS) is characterized by a combination of developmental abnormalities and a predisposition to form various tumors. Although it is possible to create disease models via gene editing, there are significant potential problems with this approach such as off-target mutations and differences in SNPs. On the other hand, since disease families share common SNPs, research using iPSCs derived from both patients and healthy siblings of the same disease family is very important. Thus, establishment of induced pluripotent stem cells derived from patients and healthy siblings of the same NBCCS family will be of great importance to study the etiology of this disease and to develop therapeutics. In this study, we generated hiPSCs using peripheral blood mononuclear cells derived from the patients and healthy siblings of familial NBCCS with the novel mutation in PTCH1_c.3298_3299insAAG in the feeder- and serum-free culture conditions using SeVdp. In addition, disease-specific hiPSCs such as those expressing the PTCH1_c.3298_3299insAAG mutation could be powerful tools for revealing the genotype-phenotype relationship and pathogenicity of NBCCS.

Mutations of PTCH1 gene in two pedigrees with bifid rib-basal cell nevus-jaw cyst syndrome. / 肋骨分叉-基底细胞痣-é¢Œéª¨å›Šè‚¿ç»¼åˆå¾ä¸¤å®¶ç³»åŸºå› åºåˆ—å˜å¼‚åˆ†æž.

Two male patients with bifid rib-basal cell nevus-jaw cyst syndrome (BCNS) were admitted to Department of Stomatology, the First Affiliated Hospital of Bengbu Medical College due to radiological findings of multiple low density shadows in the jaw. Clinical and imaging findings showed thoracic malformation, calcification of the tentorium cerebellum and falx cerebrum as well as widening of the orbital distance. Whole exon high-throughput sequencing was performed in two patients and their family members. The heterozygous mutations of c.C2541C>A(p.Y847X) and c.C1501C>T(p.Q501X) in PTCH1 gene were detected in both patients. Diagnosis of BCNS was confirmed. The heterozygous mutations of PTCH1 gene locus were also found in the mothers of the two probands. Proband 1 showed clinical manifestations of low intelligence, and heterozygous mutations of c.C2141T(p.P714L) and c.G3343A(p.V1115I) were detected in FANCD2 gene. Proband 2 had normal intelligence and no FANCD2 mutation. The fenestration decompression and curettage of jaw cyst were performed in both patients. Regular follow-up showed good bone growth at the original lesion, and no recurrence has been observed so far.

Concurrent medulloblastoma and cardiac fibroma: a rare presentation of Gorlin-Goltz syndrome.

BACKGROUND: Gorlin-Goltz syndrome is a rare autosomal dominant disorder resulting from PTCH1 gene mutation and presents with variable clinical manifestations. The co-occurrence of medulloblastoma and cardiac fibroma in Gorlin-Goltz syndrome is extremely rare. The present article discusses a patient diagnosed with Gorlin-Goltz syndrome and concurrent medulloblastoma and cardiac fibroma. CASE PRESENTATION: A 19-month-old boy transferred to our hospital after a radiological finding of posterior fossa lesion and hydrocephalus. A pericardial mass was noted after persistent arrhythmias. Both tumors were excised for definitive management. The histopathological sections were diagnostic of desmoplastic nodular medulloblastoma, WHO grade 4 and cardiac fibroma. Molecular and genetic investigations confirmed a pathogenic variant of PTCH1 gene, suggestive of autosomal dominant Gorlin-Goltz syndrome. CONCLUSION: Co-occurrence of medulloblastoma and cardiac fibroma is extremely rare and poses a management dilemma. Genetic counseling and antenatal screening are of utmost importance to early detect and manage patients with Gorlin-Goltz syndrome.

[Basal cell nevus syndrome: the interface between dentistry and dermatology]. / Het basaalcelnaevussyndroom: raakvlak tussen tandheelkunde en dermatologie.

Basal cell nevus syndrome is a rare, autosomal dominant disorder, predominantly caused by a mutation in the PTCH1 gene. As basal cell carcinomas and keratocysts are the most common abnormalities, dermatologists, orofacial maxillary surgeons, and dentists play a key role in patient care. From the age of 8, screening for odontogenic keratocysts with an orthopantomogram or MRI is recommended every other year. The intensity increases to annual screening after the development of the first odontogenic keratocyst. If BCNS is caused by an underlying SUFU mutation, screening is not indicated since there are no reports of odontogenic keratocyst in these patients to date. Radiation exposure by, for example, computed tomography, should be minimized as it induces new BCCs. Regular follow-up by a dermatologist for early diagnosis and treatment of (multiple) BCC's is recommended for life.

Perspectives on the implications of carrying putative pathogenic variants in the medulloblastoma predisposition genes ELP1 and GPR161.

Recent genetic sequencing studies in large series' of predominantly childhood medulloblastoma have implicated loss-of-function, predominantly truncating, variants in the ELP1 and GPR161 genes in causation of the MBSHH subtype specifically. The latter association, along with a report of an index case with some features of Gorlin syndrome has led to speculation that GPR161 may also cause Gorlin syndrome. We show that these genes are associated with relatively low absolute risks of medulloblastoma from extrapolating lifetime risks in the general population and odds ratios from the population database gnomAD. The projected risks are around 1 in 270-430 for ELP1 and 1 in 1600-2500 for GPR161. These risks do not suggest the need for MRI screening in infants with ELP1 or GPR161 variants as this is not currently recommended for PTCH1 where the risks are equivalent or higher. We also screened 27 PTCH1/SUFU pathogenic variant-negative patients with Gorlin syndrome for GPR161 and found no suspicious variants. Given the population frequencies of 0.0962% for GPR161 and 0.0687% for ELP1, neither of these genes can be a cause of Gorlin syndrome with an unexplained population frequency far lower at 0.0021%.

SUFU-associated Gorlin syndrome: Expanding the spectrum between classic nevoid basal cell carcinoma syndrome and multiple hereditary infundibulocystic basal cell carcinoma.

Basal cell nevus syndrome (BCNS), also known as Gorlin syndrome, is characterized by an aberrant activation of the hedgehog (Hh) pathway, most cases being caused by PTCH1 mutations. However, certain features such as multiple hereditary infundibulocystic basal cell carcinomas (MHIBCC), sclerotic fibromas, childhood medulloblastoma or meningioma may be relatively specific to a SUFU mutation. We present two patients with MHIBCC, along with a more complex cutaneous and extracutaneous phenotype. MHIBCC syndrome and BCNS may share clinical features and, indeed, both syndromes probably represent different degrees of upregulation in the Hh pathway.

Comparative Molecular Genetics of Odontogenic Keratocysts in Sporadic and Syndromic Patients.

Odontogenic keratocysts (OKCs) are common cysts of odontogenic origin that usually occur as a single nonsyndromic cyst in isolation (sporadic) or as syndromic multiple cysts as a manifestation of naevoid basal cell carcinoma syndrome. Alterations involving the PTCH gene are the most commonly identified factor associated with up to 85% and 84% of naevoid basal cell carcinoma syndrome and sporadic cases, respectively. Other Hedgehog pathway and non-Hedgehog pathway-associated genes have been implicated in the pathogenesis of OKCs. This pilot study used the Affymetrix OncoScan molecular assay to perform a comparative genomic analysis between 4 sporadic and 3 syndromic cases of OKC to identify molecular drivers that may be common and/or distinct in these 2 groups. The majority of alterations detected in both groups were copy number neutral loss of heterozygosity. Despite distinct molecular signatures observed in both groups, copy number neutral loss of heterozygosity alterations involving chromosome 9q affecting not only PTCH but also the NOTCH1 gene were detected in all syndromic and 3 sporadic cases. Loss of heterozygosity alterations involving 16p11.2 affecting genes not previously described in OKCs were also detected in all syndromic and 3 sporadic cases. Furthermore, alterations on 22q11.23 and 10q22.1 were also detected in both groups. Of note, alterations on 1p13.3, 2q22.1, and 6p21.33 detected in sporadic cases were absent in all syndromic cases. This study demonstrates that a more common group of genes may be affected in both groups of OKCs, whereas other alterations may be useful in distinguishing sporadic from syndromic cysts. These findings should be validated in larger OKC cohorts to improve molecular diagnosis and subsequent patient management.

Clinical, radiographic, pathological and inherited characteristics of odontogenic keratocyst in nevoid basal cell carcinoma syndrome: a study in three Chilean families.

INTRODUCTION: Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant condition characterized by the development of odontogenic keratocyst (OKC), basal cell carcinomas and palmar-plantar pits among other conditions. Reports about Latin American population are scarce. OBJECTIVE: To analyze the clinical, radiographic, histopathologic and inherited features of odontogenic keratocyst and palmar pits in three Chilean families with nevoid basal cell carcinoma syndrome. MATERIAL AND METHODS: After histopathologic diagnosis of OKC, notified consent was requested and evaluation of the affected patients and their families was done. RESULTS: Two families appeared to have only one affected adolescent, and both of them were considered de novo cases. In the third family, three affected members participated in this study, with an autosomal dominant presentation. All affected patients had OKC and palmar pits. Basal cell carcinomas were present only among adult patients. All examined patients were from Latin American ethnic groups. CONCLUSIONS: Patients with NBCCS had single or multiple OKCs that were located more frequently in the mandibular area. One family had autosomal dominant inheritance and the other two families were de novo cases. None of the three teenage patients had basal cell carcinomas.

Molecular mechanism of extracutaneous tumours in patients with basal cell nevus syndrome.

Basal cell nevus syndrome (BCNS) is a rare genetic disorder accompanied by a broad variety of tumours, of which basal cell carcinomas and odontogenic keratocysts are the most common. BCNS is caused by a germline or postzygotic mutation in either PTCH1 or SUFU As BCNS is a rare disease, it is difficult to establish whether less frequently occurring tumours are actually part of the syndrome. In this study, the molecular mechanism behind four extracutaneous tumours in patients with BCNS was elucidated. A leiomyoma of the testis and meningioma were confirmed to be associated with BCNS in two patients by presence of a second mutation or loss of heterozygosity in PTCH1 In a meningioma of a patient with a mosaic postzygotic PTCH1 mutation an association could not be conclusively confirmed. SUFU was probably not involved in the development of a thyroid carcinoma in a patient with a germline SUFU mutation. Hence, we have proven that meningioma and leiomyoma of the testis are rare extracutaneous tumours that are part of BCNS.

Gorlin Syndrome Associated With a Solitary Circumscribed Retinal Astrocytic Proliferation in a Pediatric Patient.

Gorlin syndrome is a rare autosomal dominant disorder with near complete penetrance. The underlying genetic mechanism is a mutation in a tumor suppressor gene. Thus far, mutations in patched homolog 1 and 2 genes (PTCH1 and PTCH2) and the suppressor of fused gene (SUFU) have been identified. The syndrome is characterized by neoplasms arising early in childhood as well as developmental abnormalities, including ophthalmic anomalies. We present the first case associating Gorlin syndrome with a rare retinal lesion known as solitary circumscribed retinal astrocytic proliferation (SCRAP). SCRAP is a benign, stable retinal tumor. For this reason, it is essential to differentiate it from similar retinal lesions that are associated with poor prognosis. [Ophthalmic Surg Lasers Imaging Retina 2022;53:514-516.].

Distinct non-clock-like signatures of the basal cell carcinomas from three sisters with a lethal Gorlin-Goltz syndrome.

BACKGROUND: Gorlin-Goltz syndrome (GS) is an inherited disease characterized by predisposition to basal cell carcinomas (BCCs) and various developmental defects, whose numerous disease-causing PTCH1 mutations have been identified in the hedgehog (Hh) signaling pathway. METHODS: In this study, whole exome sequencing was used to screen for both somatic and germline deleterious mutations in three sisters with a lethal GS. The mutations we found were confirmed by subcloning and Sanger sequencing of the genomic DNA. RNA-seq was performed to profile gene expression in paired BCCs samples and the expression levels for selected genes were validated by quantitative PCR. RESULTS: The clinical and histopathologic features were analyzed for the proband in the three-generation GS family. We identified the insertion mutation PTCH1 c.1341dupA (p. L448Tfs*49), which segregated with BCC phenotype and contributed to the death of two in four patients from a Chinese family with GS. Compared with adjacent non-cancerous tissues (ANCT), four second-hit mutations were found in four of the six pairs of BCC from three patients. Of note, somatic genomic alterations in all six BCC samples were mainly clustered into non-clock-like Signature 7 (ultraviolet mutagenesis) and 11 (related to certain alkylating agents). Both RNA-seq and quantitative RT-PCR confirmed that the mRNA levels of PTCH1 and its effector GLI1 were markedly upregulated in six pairs of BCC samples versus ANCT. CONCLUSIONS: The distinct non-clock-like signatures of BCCs indicated that GS was not a life-threatening illness. The main reasons for untimely death of GS patients were PTCH1 mutation, exposure to intense ultraviolet radiationand the poor economic conditions.

Case report of bilateral ovarian fibromas associated with de novo germline variants in PTCH1 and SMARCA4.

BACKGROUND: Ovarian sex cord-stromal tumors (OSCTs) are rare ovarian tumors that can develop from sex cord, stromal cells, or both. OSCTs can be benign or malignant. Bilateral and/or unilateral ovarian fibromas, a type of OSCT of the stromal cells, have been reported in individuals diagnosed with nevoid basal cell carcinoma syndrome (NBCCS). Calcified ovarian fibromas have been reported in 15-25% of individuals diagnosed with NBCCS while 75% of those cases occur bilaterally. The average age at diagnosis of OSCT/ovarian fibromas in patients with NBCSS is in the second to third decade compared with age 50 in the general population. Ovarian tumors are rare in pediatric populations. METHODS: The patient is a 5-year-old female diagnosed with bilateral ovarian fibromas at age 4. Multigene panel for the patient and subsequent targeted molecular evaluation of parents were completed. Histological evaluations on the surgically resected ovaries were performed for microscopic characterization of fibromas. RESULTS: Germline testing identified de novo heterozygous novel likely pathogenic variants in PTCH1 gene, exon 12 deletion, and an SMARCA4 splicing variant c.2002-1G > A. Microscopic examination of bilateral tumors was consistent with an ovarian fibroma. CONCLUSIONS: To our knowledge, this is the first report of bilateral benign ovarian fibroma in a child with a diagnosis of nevoid basal cell carcinoma syndrome (NBCCS) with a potential predisposition to Rhabdoid Tumor Predisposition Syndrome (RTPS).

Decoding a gene expression program that accompanies the phenotype of sporadic and basal cell nevus syndrome-associated odontogenic keratocyst.

BACKGROUND: Odontogenic keratocyst is characterized by local aggressive behavior and a high recurrence rate, as well as its potential to develop in association with the basal cell nevus syndrome. The aim of this study was to decode the gene expression program accompanying odontogenic keratocyst phenotype. METHODS: 150-bp paired-end RNA-sequencing was applied on six sporadic and six basal cell nevus syndrome-associated whole-tissue odontogenic keratocyst samples in comparison to six dental follicles, coupled with bioinformatics and complemented by immunohistochemistry. RESULTS: 2654 and 2427 differentially expressed genes were captured to characterize the transcriptome of sporadic and basal cell nevus syndrome-associated odontogenic keratocysts, respectively. Gene ontologies related to "epidermis/skin development" and "keratinocyte/epidermal cell differentiation" were enriched among the upregulated genes (KRT10, NCCRP1, TP63, GRHL3, SOX21), while "extracellular matrix organization" (ITGA5, LOXL2) and "odontogenesis" (MSX1, LHX8) gene ontologies were overrepresented among the downregulated genes in odontogenic keratocyst. Interestingly, upregulation of various embryonic stem cells markers (EPHA1, SCNN1A) and genes committed in cellular reprogramming (SOX2, KLF4, OVOL1, IRF6, TACSTD2, CDH1) was found in odontogenic keratocyst. These findings were highly shared between sporadic and basal cell nevus syndrome-associated odontogenic keratocysts. Immunohistochemistry verified SOX2, KLF4, OVOL1, IRF6, TACSTD2/TROP2, CDH1/E-cadherin, and p63 expression predominantly in the odontogenic keratocyst suprabasal epithelial layers. CONCLUSION: The odontogenic keratocyst transcriptomic profile is characterized by a prominent epidermal and dental epithelial fate, a repressed dental mesenchyme fate combined with deregulated extracellular matrix organization, and enhanced stemness gene signatures. Thus, we propose a developed epidermis-like phenotype in the odontogenic keratocyst suprabasal epithelial cells, established in parallel to a significant upregulation of marker genes related to embryonic stem cells and cellular reprogramming.

Family history is key to the interpretation of exome sequencing in the prenatal context: unexpected diagnosis of Basal Cell Nevus Syndrome.

OBJECTIVES: To reach a molecular diagnosis for a family with two consecutive fetuses presenting with multiple congenital anomalies. METHODS: The two fetuses underwent prenatal ultrasound, autopsy, radiologic, and genetic investigation. Genetic analysis included karyotype and array-CGH for both fetuses and trio-based whole exome sequencing (WES) only for the second fetus. RESULTS: WES results, initially focusing on recessive or dominant de novo variants, were negative.However, as a result of new relevant information regarding family history, the variant c.648_651dup in the PTCH1 gene was identified as causative of the fetal phenotype. CONCLUSIONS: This case further highlights how WES data analysis and interpretation strongly rely on family history and robust genotype-phenotype correlation. This is even more relevant in the prenatal setting, where access to fetal phenotype is limited and prenatal recognition of many morbid genes is not fully explored. We also provide a detailed description of the prenatal manifestations of Basal Cell Nevus Syndrome.