Paeds · genetics-dysmorphology-and-metabolism
Marfan syndrome and heritable connective-tissue disorders
Also known as Marfan syndrome · MFS · Marfanoid habitus · Loeys-Dietz syndrome · Ehlers-Danlos syndrome · Vascular Ehlers-Danlos syndrome · Congenital contractural arachnodactyly · Beals syndrome · Heritable thoracic aortic disease
A fellowship approach to Marfan syndrome and the heritable connective-tissue disorders: recognise the marfanoid child, confirm Marfan with the revised Ghent nosology and FBN1 sequencing rather than a karyotype, image the aortic root from diagnosis and protect it for life with beta-blockade or losartan and elective valve-sparing root repair, and separate Marfan from Loeys-Dietz syndrome, vascular and hypermobile Ehlers-Danlos, Beals syndrome and homocystinuria by gene and by the direction the lens has fallen.
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Target exams
Red flags
- Any marfanoid child (tall, long limbs, pectus, lens or heart finding) needs an aortic-root echocardiogram now — dissection in undiagnosed Marfan is a cause of sudden death in the young
- Acute chest or back pain in a tall adolescent or young adult — presume type-A aortic dissection until imaging proves otherwise
- A marfanoid child whose lens has fallen downward and inward, with intellectual disability or thrombosis — exclude homocystinuria with a plasma homocysteine before labelling as Marfan
- Bifid uvula or cleft palate with hypertelorism and arterial tortuosity — think Loeys-Dietz syndrome, where dissection occurs at smaller diameters and younger ages
- Easy bruising, translucent skin, or unexplained bowel or arterial rupture in a thin child — exclude vascular Ehlers-Danlos (COL3A1) before any invasive procedure
- A young woman with Marfan syndrome who wants to conceive with an aortic root over 4.0 cm — refer for pre-pregnancy root repair before conception
- A first-degree relative of a confirmed case who has not had genetic assessment — cascade testing is mandatory for these autosomal-dominant disorders
Life stages
Care settings
Clinical exam formats
Board mappings
- Recognition of the marfanoid phenotype and indications for aortic-root imaging
- Indications for FBN1 genetic testing and cardiology referral
- Aortic-root surveillance and the role of beta-blockade
- The revised Ghent nosology and the systemic score
- Heritable connective-tissue-disorder differential including Loeys-Dietz and vascular Ehlers-Danlos
- Timing of elective valve-sparing aortic-root replacement and pre-pregnancy counselling
- Assessing a child with suspected Marfan syndrome
- Genetic counselling of an autosomal-dominant connective-tissue disorder
- Coordinating cardiology, ophthalmology, orthopaedics and clinical genetics
- Long case of a marfanoid adolescent with aortic-root dilation
- Counselling a family on Marfan versus Loeys-Dietz and reproductive risk
- Genetic causes of multisystem disease and cardiac risk
- Communication in lifelong chronic genetic disease
- Safeguarding and transition to adult care
- Marfan syndrome genetics and the revised Ghent nosology
- Loeys-Dietz and vascular Ehlers-Danlos syndromes
- Aortic-root surveillance and the marfanoid differential
- Musculoskeletal and ocular examination of the marfanoid child
- Counselling on genetic testing and lifelong surveillance
- Marfan syndrome and the heritable connective-tissue disorders
- Evaluation of the tall child with aortic dilation
- Genetic counselling and cascade family testing
- Marfan syndrome
- Heritable connective-tissue disorders and aortic disease
- Multidisciplinary care of chronic multisystem genetic disease
- Marfan syndrome and heritable thoracic aortic disease
- The marfanoid differential and aortic surveillance
- Multidisciplinary care of inherited connective-tissue disorders
The candidate who wins the marks holds three layers in view at once. The first is the child in front of you: their stature, their limbs, their lens, their heart, and the aortic root that quietly dilates until it tears. The second is the molecule: a fibrillin-1 defect that breaks the elastic-fibre scaffold and, just as importantly, releases the brake on transforming growth factor-beta (TGF-beta), the signalling discovery that reframed the whole disease. The third is the family: because Marfan and its relatives are autosomal dominant, every first-degree relative carries a one-in-two chance and deserves assessment and counselling. [1] [3]
Overview & Definition
Marfan syndrome is an autosomal-dominant disorder of fibrillin-1, a large glycoprotein that is the building block of the microfibrils scaffolding elastic fibres throughout the body. When fibrillin-1 is defective the load-bearing tissues — the aortic wall, the suspensory ligament of the lens, dura, lungs and the growing skeleton — lose their structural integrity in a predictable pattern. Marfan is the commonest of the heritable connective-tissue disorders and the one a general paediatrician is most likely to meet, affecting roughly one in 3,000 to 5,000 people of all populations. [1] [2]
Around the core diagnosis sits a family of related conditions that share a marfanoid habitus or a connective-tissue mechanism but differ sharply in their gene, their lens, and the behaviour of their arteries. Loeys-Dietz syndrome is driven by signalling defects in the TGF-beta pathway (TGFBR1 or TGFBR2, and the related SMAD3, TGFB2 and TGFB3 genes) and produces aggressive, early arterial aneurysms and dissections alongside a cleft palate, bifid uvula and hypertelorism. Vascular Ehlers-Danlos syndrome is a type-III collagen defect (COL3A1) that causes fragile arteries, spontaneous bowel rupture and the gravest prognosis in the family. Congenital contractural arachnodactyly (Beals syndrome) is an FBN2 disorder that mimics Marfan but adds congenital joint contractures and crumpled ears. [6] [8] [10]
The trap the fellowship candidate must avoid is the tall child labelled "Marfan" on habitus alone. The lens that has fallen downward and inward belongs to homocystinuria, a treatable autosomal-recessive enzyme defect whose thrombotic and cognitive course is entirely different. Separating these conditions is not a naming exercise — it sets the surveillance schedule, surgical thresholds, reproductive counselling and, in homocystinuria, the diet and vitamin therapy that change the outcome. [9] [2]
References11ShowHide
- [1]Dietz H FBN1-related Marfan syndrome. GeneReviews, 1993.PMID 20301510
- [2]Loeys BL, Dietz HC, Braverman AC, Callewaert BL, De Backer J, Devereux RB, et al. The revised Ghent nosology for the Marfan syndrome. J Med Genet, 2010.PMID 20591885
- [3]Neptune ER, Frischmeyer PA, Arking DE, Myers L, Bunton TE, Gayraud B, et al. Dysregulation of TGF-beta activation contributes to pathogenesis in Marfan syndrome. Nat Genet, 2003.PMID 12598898
- [4]Lacro RV, Dietz HC, Sleeper LA, Yetman AT, Bradley TJ, Colan SD, et al. Atenolol versus losartan in children and young adults with Marfan's syndrome. N Engl J Med, 2014.PMID 25405392
- [5]Robertson DM, Truong DT, Cox DA, et al. Pediatric Heart Network trial of losartan vs. atenolol in children and young adults with Marfan syndrome: impact on prespecified subgroups. Pediatr Cardiol, 2023.PMID 35902413
- [6]Loeys BL, Chen J, Neptune ER, Judge DP, Podowski M, Holm T, et al. A syndrome of altered cardiovascular, craniofacial, neurocognitive and skeletal development caused by mutations in TGFBR1 or TGFBR2. Nat Genet, 2005.PMID 15731757
- [7]MacCarrick G, Black JH, Bowdin S, El-Hamamsy I, Frischmeyer-Guerrerio PA, Guerrerio AL, et al. Loeys-Dietz syndrome: a primer for diagnosis and management. Genet Med, 2014.PMID 24577266
- [8]Malfait F, Francomano C, Byers P, Belmont J, Berglund B, Black J, et al. The 2017 international classification of the Ehlers-Danlos syndromes. Am J Med Genet C Semin Med Genet, 2017.PMID 28306229
- [9]Sacharow SJ, Levy HL Homocystinuria due to Cystathionine Beta-Synthase Deficiency. GeneReviews, 1993.PMID 20301697
- [10]Callewaert B Congenital contractural arachnodactyly. GeneReviews, 1993.PMID 20301560
- [11]Isselbacher EM, Preventza O, Hamilton Black I, Augoustides JG, Beck AW, Bolen MA, et al. 2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: a report of the American Heart Association. Circulation, 2022.PMID 36322642