Última actualización:
11/17/2023
Años publicados: 1989, 1999, 2000, 2009, 2012, 2015, 2018, 2023
NORD gratefully acknowledges Lewis B. Holmes, MD, Emeritus Chief, Medical Genetics and Metabolism Unit, Mass General for Children, and Professor of Pediatrics, Harvard Medical School, for assistance in the preparation of this report.
Amniotic band syndrome is a well-known condition associated with a variety of birth defects. The abnormalities occur in the early weeks of pregnancy after the affected parts of the body have formed normally. The severity of amniotic band syndrome can range from a single, isolated finding to multiple, disfiguring complications. The arms and legs are most often affected. The head and face and, in some patients, various internal organs can also be affected. The exact cause of amniotic band syndrome is unknown and is controversial.
Several different patterns of birth defects have been identified with amniotic band syndrome. The three most common patterns are amniotic band syndrome characterized by one or more limbs being affected; the limb-body-wall complex; and amniotic band syndrome characterized by abnormalities of the head and face (craniofacial abnormalities), defects of the brain and serious malformation of the arms and legs.
Most infants with amniotic band syndrome have some form of deformity of the fingers and toes. Upper limbs are affected more often than lower limbs. In some patients, one limb or one hand or foot may be the only symptom of the disorder. The specific physical features can include abnormally short fingers or toes and absence of the end (distal portion), webbing (fusion) of fingers or toes (syndactyly), constriction rings and extra strands of tissue adhering to the fingers. The constriction rings that encircle a limb or digit can alter blood flow.
Another pattern associated with amniotic band syndrome is referred to as the limb-body wall complex, a lethal condition. Affected infants have protrusion of the soft internal organs of the body (viscera) the abdominal or chest cavities through a fissure in the abdominal wall (abdominoschisis) or the chest wall (thoracoschisis), and a variety of defects affecting the arms and legs.
A third patterns associated with amniotic band syndrome involves craniofacial abnormalities such as incomplete closure of the roof of the mouth (cleft palate), facial clefts, small, underdeveloped eyes (microphthalmia), narrowing of the nasal passages (choanal atresia) and malformations affecting the size and shape of the skull. In some infants, the head is attached to the placenta.
The proposed causes and underlying mechanisms that cause amniotic band syndrome are complex. The two main theories are known as the extrinsic theory and the intrinsic theory. The extrinsic theory states that amniotic band syndrome occurs due to factors found outside of the fetus (externally). The intrinsic theory states that amniotic band syndrome occurs due to factors found within the fetus (internally).
Extrinsic Theory
The extrinsic theory for the development of amniotic band syndrome is that strands of tissue separate from the inner layer (amnion) of the amniotic sac. The amniotic sac is the thin membrane that surrounds an embryo or developing fetus (amniotic sac). The sac contains a liquid (amniotic fluid), which supports, cushions and protects a developing fetus. The amniotic sac is composed of two main layers – the outer layer called the chorion, and the inner layer is called the amnion. According to this theory, the inner layer (amnion) of the amniotic sac ruptures or tears, exposing the fetus to strands of fibrous tissue that may float freely in the amniotic fluid or remain partially attached to the amniotic sac. These bands of tissue can disrupt the normal development of a fetus. The bands of tissue can wrap around or entangle (constrict) the fingers, toes, arms, legs and other parts of the developing fetus as when a rubber band had been tightly wrapped around an arm or leg or another body part. The symptoms that occur due to amniotic bands depend on the specific part of the body affected by these strands of tissue and how tightly they have wrapped around a body part. If the amniotic bands are still partially attached to the amniotic sac, they may wrap around a fetal body part and tether (anchor) that body part to the amniotic sac. This can restrict movement and proper development of the affected fetus.
The extrinsic theory fails to explain why some affected infants have an intact amniotic sac with amniotic band syndrome; why there are a high number of malformations affecting internal organs in some patients; and why some infants have defects of parts of the body not affected by amniotic (constriction) bands.
Intrinsic Theory
The intrinsic theory attributes the features of the amniotic band syndrome to impaired blood flow (circulation) to specific parts of the developing fetus (vascular disruption or compromise). In areas where the blood flow is poor, injury occurs to the blood vessel walls of the fetus. This leads to bleeding (hemorrhaging) and tissue loss in the affected areas, which in turn results in the varied symptoms associated with the disorder. The intrinsic theory attributes the presence of constriction bands as a secondary effect of the impaired blood flow and subsequent damage to the fetus. In a 1987 article in the journal Teratology, Webster, et al. demonstrated this theory of vascular disruption with an intact amnion in animal models.
In some patients, specific environmental factors have been identified. In some infants, trauma to the abdominal area during pregnancy or blunt trauma to the placenta seemed to have caused the amniotic band syndrome.
Some infants have been affected after the performance of a diagnostic technique called chorionic villus sampling (CVS), when performed early (before 10 weeks) during pregnancy. This prenatal test is performed to detect certain problems in a fetus such as chromosomal abnormalities or certain genetic disorders. During the procedure, tissue is removed from the placenta and certain cells called chorionic villi are studied. In a small number of infants, the CVS procedure produces blood loss, low blood pressure and vascular disruption. One estimate of the risk for this occasional risk is 1 in 2,000 CVS procedures.
Intense uterine contractions caused by a drug known as misoprostol (a prostaglandin E1 analogue) has resulted in amniotic band syndrome. Misoprostol is approved by the U.S. Food and Drug Administration (FDA) for the treatment of gastric ulcers. In addition, misoprostol is used to induce abortion. If the pregnancy continues after the use of misoprostol to 6 to 8 weeks of pregnancy, the infant may have the amniotic band syndrome.
The exact cause of impaired fetal blood flow, as suggested by the intrinsic theory, is unknown. It has been noted that the amniotic band syndrome occurs with greater frequency in first pregnancies, problem pregnancies or premature births. Young females and females of African descent also have higher rates of infants with amniotic band syndrome. Some genetic studies (by Hunter, et al. and Carmichael, et al.) have identified intrinsic, genetic factors that may predispose infants to the development of amniotic band syndrome (genetic predisposition). A genetic predisposition to developing a disorder means that a person carries a gene variant or multiple gene variants, that increases the risk for the disorder.
Although genetic factors are believed to play a role in the development of some cases of amniotic band syndrome, the risk of recurrence in a subsequent child is extremely low. Most affected infants have no other affected relatives.
Amniotic band syndrome is estimated to occur in anywhere from 1 in 1,200 to 15,000 live births. No gender or ethnic predispositions have been identified with amniotic band syndrome.
In the surveillance of almost 300,000 births in a Boston hospital over many years (Holmes, et al.), 40 infants (1 in 7,500) with amniotic band syndrome were identified, including several with recognized causes.
Amniotic band syndrome is typically diagnosed at birth or soon after birth based upon characteristic physical findings. The minimal diagnostic criteria consist of the detection of certain abnormalities of the arms, legs, fingers and/or toes, i.e., ring-like constriction or amputation defects, fusion (syndactyly) between some digits and/or strands of tissue attached to the ends of affected fingers.
In some cases, the condition may be suspected before birth (prenatally), based upon the results of certain specialized imaging techniques, such as fetal ultrasonography, which may reveal the characteristic features. During fetal ultrasonography, reflected high-frequency sound waves are used to create an image of the developing fetus.
It is important to be certain of the diagnosis, as “the amniotic band syndrome” is well-known and readily assigned by physicians. One helpful clue to make a diagnosis is to look at the membranes of the affected infant’s placenta on the first day of life. A specialized examination by a perinatal pathologist will identify absence of the amnion on the chorionic surface of the membranes of the amnionic sac (Moerman, et al.), a sign of amnion rupture that confirms the diagnosis. However, it is not routine practice to look for absence of the amnion when examining the placenta.
Treatment
The treatment of infants and children with amniotic band syndrome is symptomatic and supportive. For example, in infants with incomplete development of the lungs and associated respiratory insufficiency, treatment may include oxygen support measures and other supportive therapies as required. Reconstructive surgery or other surgical techniques may be recommended to help correct or repair associated malformations, such as ring-like constrictions of the limbs, webbed fingers and toes, cleft lip or club foot. Physical and occupational therapy may also be necessary to ensure infants can attain the optimal use of affected fingers, toes, arms and legs.
In rare cases, surgery has been performed (Minella, et al.) during pregnancy to cut amniotic bands that are tightly constricting and could cause loss of a limb or digit.
Research is currently ongoing to determine whether there are any underlying risk factors such as genetic factors that may make it more likely for amniotic band syndrome to occur.
All information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government website.
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For information about clinical trials sponsored by private sources, contact: www.centerwatch.com
For information about clinical trials conducted in Europe, contact: https://www.clinicaltrialsregister.eu/
TEXTBOOKS
Jones KL, Jones MC, Del Campo M. Smith’s Recognizable Patterns of Human Malformation: Expert Consult. 8th ed. Elsevier; 2021.
Stevenson RE, Hall JG. Human Malformations and Related Anomalies. 2nd ed. New York, NY: Oxford University Press; 2005:871-875.
Paletta CE, Roth FS. Amniotic Bands. NORD Guide to Rare Disorders. Philadelphia, PA: Lippincott Williams & Wilkins; 2003:150-151.
JOURNAL ARTICLES
Carmichael SL, Shaw GM, Iovannisci DM, et al. Risks of human limb deficiency anomalies associated with 29 SNPs of genes involved in homocysteine metabolism, coagulation, cell-cell interactions, inflammatory response, and blood pressure response, and blood pressure regulation. Am J Med Genet A. 2006;140:2433- 2440.
Demetri LRF, Starcevich AG, Manske CB, James MA. Clinical manifestations of constriction band syndrome. J Bone Joint Surg AM 2022; 104:1301-1310.
Firth HV, Boyd PA, Chamberlain PF, et al. Analysis of limb reduction defects in babies exposed to chorionic villus sampling. Lancet. 1994;343:1069-1071.
Hennekam RCM, Hofstee N. Familial liability to intrauterine vascular impairments. Pediatrics. 1990;86:326-327.
Holmes LB, Nasri HZ. Terminal transverse limb defects with “nubbins”. Birth Defects Research 2021; 113:1007-1014.
Holmes LB, Westgate M-N, Nasri H, Toufaily MH. Malformations attributed to the process of vascular disruption. Birth Defects Research. 2018;110:98-107.
Hunter AG. A pilot study of the possible role of familial defects in anticoagulation as a cause for terminal limb reduction malformations. Clin Genet. 2000;57:197-204.
Inglesby DC, Janssen PL, Graziano FD et al. Amniotic band syndrome: head-to-toe manifestations and clinical management guidelines. Plast Reconstr Surg 2023; 152:338e.
Minella C, Costantino B, Ruano R et al. Fetoscopic release of amniotic band syndrome. J Ultrasound in Medicine 2021; 40:1039-1048.
Moerman P, Fryns JP, Vandenberghe K, Lauweryns JM. Constriction amniotic bands, amniotic adhesions and limb-body wall complex: discrete disruptive sequences with pathogenetic overlap. Am J Med Genet 1992; 42-470-479.
Robin NH, Franklin J, Prucka S, Ryan AB, Grant JH. Clefting, amniotic bands, and polydactyly: a distinct phenotype that supports an intrinsic mechanism for amniotic band sequence. Am J Med Genet A. 2005;137A:298-301.
Viljoen DL. Porcephaly and transverse limb defects following severe maternal trauma in early pregnancy. Clin Dysmorphol. 1995;4:75- 78.
Webster WS, Lipson AH, Brown-Woodman PD. Uterine trauma and limb defects. Teratology. 1987;35:253-260.
Werler MM, Louik C, Mitchell AA. Epidemiologic analysis of maternal factors and amniotic band defects. Birth Def Res (Part A). 2003;67:68-72.
INTERNET
Do TT. Streeter Dysplasia. Medscape. Updated: Sept 7, 2022. https://emedicine.medscape.com/article/1260337-overview Accessed Nov 8, 2023.
Online Mendelian Inheritance in Man (OMIM). The Johns Hopkins University. Constricting Bands, Congenital. Entry No: 217100. Last Edited: 09/27/2011. Available at: https://omim.org/entry/217100 Accessed Nov 8, 2023.
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Aprende más https://rarediseases.org/patient-assistance-programs/caregiver-respite/The information provided on this page is for informational purposes only. The National Organization for Rare Disorders (NORD) does not endorse the information presented. The content has been gathered in partnership with the MONDO Disease Ontology. Please consult with a healthcare professional for medical advice and treatment.
The Genetic and Rare Diseases Information Center (GARD) has information and resources for patients, caregivers, and families that may be helpful before and after diagnosis of this condition. GARD is a program of the National Center for Advancing Translational Sciences (NCATS), part of the National Institutes of Health (NIH).
View reportOrphanet has a summary about this condition that may include information on the diagnosis, care, and treatment as well as other resources. Some of the information and resources are available in languages other than English. The summary may include medical terms, so we encourage you to share and discuss this information with your doctor. Orphanet is the French National Institute for Health and Medical Research and the Health Programme of the European Union.
View reportOnline Mendelian Inheritance In Man (OMIM) has a summary of published research about this condition and includes references from the medical literature. The summary contains medical and scientific terms, so we encourage you to share and discuss this information with your doctor. OMIM is authored and edited at the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine.
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