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Clinical Characteristics: Cranioectodermal dysplasia (CED) is a ciliopathy with skeletal involvement (narrow thorax, shortened proximal limbs, syndactyly, polydactyly, brachydactyly), ectodermal features (widely spaced hypoplastic teeth, hypodontia, sparse hair, skin laxity, abnormal nails), joint laxity, growth deficiency, and characteristic facial features (frontal bossing, low-set simple ears, high forehead, telecanthus, epicanthal folds, full cheeks, everted lower lip). Most affected children develop nephronophthisis that often leads to end-stage kidney disease in infancy or childhood, a major cause of morbidity and mortality. Hepatic fibrosis and retinal dystrophy are also observed. Dolichocephaly, often secondary to sagittal craniosynostosis, is a primary manifestation that distinguishes CED from most other ciliopathies. Brain malformations and developmental delay may also occur., Diagnosis/testing: The diagnosis of CED is established in a proband with characteristic clinical and radiographic features (including two frequent features and two other abnormalities, with at least one ectodermal defect – i.e., involvement of the teeth, hair, or nails) and/or by identification of biallelic pathogenic variants in one of the six genes currently known to be associated with CED: IFT43 , IFT52 , IFT122 , IFT140 , WDR19 , or WDR35 ., Management: Treatment of manifestations: As needed, surgery to correct sagittal craniosynostosis usually before age one year. Surgical correction may be needed for polydactyly of the hands and feet. Orthopedic care for hip dysplasia. Human growth hormone therapy could be considered in those who meet standard treatment criteria. Standard treatment for dental anomalies, nephronophthisis, liver disease, cardiac anomalies, and/or inguinal and umbilical hernias. For those with progressive visual impairment: low vision aids and appropriate educational programs. Mechanical ventilation may be required in newborns with pulmonary hypoplasia. For those with developmental delay, speech and physical therapy and appropriate educational programs. Surveillance: In infancy and childhood: monitor tooth development; morning urine osmolarity testing, urine collection assay for polyuria, blood pressure, serum creatinine and blood urea assessment, and renal ultrasound as recommended by nephrologist; hepatic transaminases and measurement of synthetic liver function as recommended by hepatologist. Annual ophthalmologic examinations starting at age four years to detect early signs of retinal degeneration. Cardiac examinations, ECG, and echocardiography per cardiologist. Review of developmental progress at each primary care visit, and formal evaluation with neuropsychological testing if delays noted., Genetic Counseling: CED is inherited in an autosomal recessive manner. If both parents are known to be heterozygous for a CED-causing pathogenic variant, each sib of an affected individual has at conception a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. Carrier testing for at-risk relatives, prenatal testing for a pregnancy at increased risk, and preimplantation genetic testing are possible once the CED-causing pathogenic variants have been identified in an affected family member. Second-trimester ultrasound examination may detect renal cysts, shortening of the limbs, and/or polydactyly., (Copyright © 1993-2021, University of Washington, Seattle. GeneReviews is a registered trademark of the University of Washington, Seattle. All rights reserved.)

Clinical Characteristics: PIK3CA -related overgrowth spectrum (PROS) encompasses a range of clinical findings in which the core features are congenital or early-childhood onset of segmental/focal overgrowth with or without cellular dysplasia. Prior to the identification of PIK3CA as the causative gene, PROS was separated into distinct clinical syndromes based on the tissues and/or organs involved (e.g., MCAP [ m egalencephaly- cap illary malformation] syndrome and CLOVES [ c ongenital l ipomatous asymmetric o vergrowth of the trunk, lymphatic, capillary, venous, and combined-type v ascular malformations, e pidermal nevi, s keletal and s pinal anomalies] syndrome). The predominant areas of overgrowth include the brain, limbs (including fingers and toes), trunk (including abdomen and chest), and face, all usually in an asymmetric distribution. Generalized brain overgrowth may be accompanied by secondary overgrowth of specific brain structures resulting in ventriculomegaly, a markedly thick corpus callosum, and cerebellar tonsillar ectopia with crowding of the posterior fossa. Vascular malformations may include capillary, venous, and less frequently, arterial or mixed (capillary-lymphatic-venous or arteriovenous) malformations. Lymphatic malformations may be in various locations (internal and/or external) and can cause various clinical issues, including swelling, pain, and occasionally localized bleeding secondary to trauma. Lipomatous overgrowth may occur ipsilateral or contralateral to a vascular malformation, if present. The degree of intellectual disability appears to be mostly related to the presence and severity of seizures, cortical dysplasia (e.g., polymicrogyria), and hydrocephalus. Many children have feeding difficulties that are often multifactorial in nature. Endocrine issues affect a small number of individuals and most commonly include hypoglycemia (largely hypoinsulinemic hypoketotic hypoglycemia), hypothyroidism, and growth hormone deficiency., Diagnosis/testing: The diagnosis of PROS is established in a proband with suggestive findings and a heterozygous mosaic (or rarely, constitutional) activating pathogenic variant in PIK3CA . Sequence analysis of DNA derived from clinically affected tissue samples ‒ preferably from freshly obtained dermal biopsy overlying an affected area, from surgical excision of the overgrown tissue, or from uncultured tissues (such as skin fibroblasts or other tissues) ‒ should be prioritized for genetic testing. Targeted capture of the entire PIK3CA coding region followed by next-generation sequencing at very deep coverage is recommended for somatic variant detection, as it allows for detection of very low levels of mosaicism throughout the gene., Management: Targeted treatment of manifestations : Alpelisib (VIJOICE ® ) 50 mg orally with food once a day (at about the same time every day) for those between age two years and <18 years with PROS. In those age six years or older, the dose may be increased to 125 mg once a day after 24 weeks. A starting dose of 250 mg orally with food once a day (at about the same time every day) has been approved for those age ≥18 years. Alpelisib has been approved specifically for the reduction of overgrowth, vascular lesions, and other functional complications. To date, it is unknown whether this drug has any efficacy in treating the neurologic manifestations of PROS (as, e.g., in MCAP syndrome). Supportive treatment of manifestations: Significant or lipomatous segmental overgrowth may require debulking; scoliosis and leg-length discrepancy may require orthopedic care and surgical intervention. Neurologic complications (e.g., obstructive hydrocephalus, increased intracranial pressure, progressive and/or symptomatic cerebellar tonsillar ectopia or Chiari malformation, and epilepsy in those with brain overgrowth/malformations) may warrant neurosurgical intervention. Depending on the type of vascular malformations, sclerotherapy, laser therapy, or oral medications such as sirolimus may be used. Similarly, lymphatic malformations may be treated through oral medications or careful surgical debulking, preferably by a vascular anomalies team. For those with pain, evaluation for the source of pain and treatment of the underlying cause is recommended. For those with growth hormone deficiency, a trial of growth hormone therapy may be considered with careful monitoring of linear growth and overgrowth. Routine treatment of the following, when present, is indicated: cardiac and renal abnormalities; intellectual disabilities and behavior problems; polydactyly and foot deformities; coagulopathy or thrombosis; Wilms tumor; hypothyroidism; and hypoglycemia. Surveillance : At each visit: measurement of growth parameters including head circumference, length of arms, hands, legs, and feet; assess for new neurologic manifestations (seizures, changes in tone, and other signs/symptoms of Chiari malformation); monitor developmental progress and behavior; assess motor skills; clinical assessment for scoliosis and abdominal examination for organomegaly and/or abdominal masses. Serial head MRI imagining is recommended, with frequency based on the severity of findings on initial assessment and the degree of brain maturation. For those with CNS overgrowth or dysplasia, brain MRI every six months until age two years and then annually until age eight years to monitor specifically for progressive hydrocephalus and Chiari malformation. As clinically indicated: clinical assessment and monitoring of any vascular and/or lymphatic malformations; radiographs of the limbs in those with overgrowth of a limb or portion of a limb; ultrasound or MRI follow up in those with truncal overgrowth; spinal MRI in those with scoliosis or deformities that affect the spine. Hematology consultation with recommendations for assessment for thrombosis and coagulopathy risk after any surgical intervention, particularly in those with the CLOVES phenotype and/or those with vascular malformations. Consideration of renal ultrasound every three months until age eight years (tumor screening for Wilms tumor is controversial)., Genetic Counseling: PROS disorders are not known to be inherited, as most identified pathogenic variants are somatic (mosaic). No confirmed vertical transmission or sib recurrence has been reported to date. The risk to sibs of a proband with somatic mosaicism for a pathogenic variant in PIK3CA would be expected to be the same as in the general population. All but a few affected individuals with PROS have had somatic mosaicism for a PIK3CA pathogenic variant, suggesting that mutation occurred post fertilization in one cell of the multicellular embryo. Therefore, the risk for transmission to offspring is expected to be less than 50%., (Copyright © 1993-2022, University of Washington, Seattle. GeneReviews is a registered trademark of the University of Washington, Seattle. All rights reserved.)