Mermaid baby with multiple congenital anomalies in monochorionic twin gestation in diabetic mother.
Twin 1-1.5kg, preterm, male baby, delivered as breech showed evidence of Mermaid anomaly, neural tube defect(spina bifida occulta--lumbar region), single kidney, single ventricle, imperforate anus, single umbilical artery, sacral agenesis. Baby died after 2 hours.
Twin 2-1.7kg, preterm, male baby, delivered as cephalic, no obvious congenital anomalies were detected.
Both mother and twin 2 were healthy and discharged on 16th day.
DISCUSSION: Sirenomelia, also known as sirenomelia sequence, is a severe malformation of the lower body characterized by fusion of the legs and a variable combination of visceral abnormalities (1). Clinical studies of sirenomelia have given rise to two main pathogenic hypotheses. The first hypothesis, based on the aberrant abdominal and umbilical vascular pattern of affected individuals, postulates a primary vascular defect that leaves the caudal part of the embryo hypoperfused. The second hypothesis, based on the overall malformation of the caudal body, postulates a primary defect in the generation of the mesoderm. Infants with cyclopia or sirenomelia are born at an approximate rate of 1 in 100 000 births (2,3).
Eight malformation monitoring systems around the world jointly studied the epidemiology of these rare malformations: 102 infants with cyclopia, 96 with sirenomelia, and one with both conditions were identified among nearly 10.1 million births. Maternal age is somewhat increased for cyclopia, indicating the likely inclusion of some chromosomally abnormal infants which were not identified. About half of the infants are stillborn. There is a female excess among infants with cyclopia. Excess twinning occurred for cyclopia and possibly also for sirenomelia (4)
In Greek mythology, the Sirens were three creatures with the head of a woman and the body of a bird from the wings down. They were dangerous to sailors, whom they narcotized with their enchanting music and voices to later kill them, despite the present perception of Sirens as romantic and cute creatures, the sirenomelia human malformation is a severe condition (1).
The diagnosis, which is obvious at birth, is currently performed by prenatal ultrasonography. Antenatal ultrasonography clues include oligohydramnios, renal agenesis and a fibula positioned between the tibiae (5)
Although the primary molecular defect underlying sirenomelia remains unknown,the two main pathogenic hypotheses are the vascular steal hypothesis and the defective blastogenesis hypothesis (6). In humans, a genetic etiology for congenital caudal anomalies has only been confirmed for the Currarino syndrome, a sacral agenesis caused by mutations in the homeobox-containing gene HLXB9 (1). By contrast, to date, all reported incidences of sirenomelia in humans have been sporadic cases. Maternal diabetes has been associated with both caudal regression syndrome and sirenomelia (7)
Although it is possible that, in humans, sirenomelia is an autosomal-dominant genetic condition, it has a combined genetic and environmental component maternal diabetes and heavy metals have been described as important environmental risk factors for caudal malformations (1).
(1.) Carlos G, Endika H, Domingo G, Maria L, Federica B, Maria A. A clinical and experimental overview of sirenomelia: insight into the mechanisms of congenital limb Malformations. Dis Model Mech 2011; 4(3): 289-299.
(2.) Bengt K, Eduardo E, Paul A, Osvaldo M, Lisbeth B, Maria L et al. The cyclops and the mermaid: an epidemiological study of two types of rare malformation. J Med Genet 1992; 29: 30-35
(3.) Suzuki K, Adachi Y, Numata T, Nakada S, Yanagita M. (2012) Reduced BMP Signaling Results in Hindlimb Fusion with Lethal Pelvic/Urogenital Organ Aplasia: A New Mouse Model of Sirenomelia. PLoS ONE 7(9): e43453. doi:10.1371/journal.pone.0043453.
(4.) Kallen B, Castilla EE, Lancaster PA, Mutchinick O, Knudsen LB, Martinez-Frias ML, Mastroiacovo P, Robert E. The cyclops and the mermaid: an epidemiological study of two types of rare malformation. J Med Genet. 1992; 29:30-35. doi: 10.1136/jmg.29.1.30.[PMC free article] [PubMed]
(5.) Van Keirsbilck J, Cannie M, Robrechts C, de Ravel T, Dymarkowski S, Van den Bosch T, Van Schoubroeck D. First trimester diagnosis of sirenomelia. Prenat Diagn. 2006;26:684-688. doi: 10.1002/pd.1479. [PubMed]
(6.) Carlos G, Domingo G, Maria A. (2012) Sirenomelia Phenotype in Bmp7;Shh Compound Mutants: A Novel Experimental Model for Studies of Caudal Body Malformations. PLoS One. 2012; 7(9): e44962. doi: 10.1371/journal.pone.0044962. PMCID: PMC3444499
(7.) Rosemary O, Augusta U, Woroma W. Sirenomelia in a Nigerian triplet: a case report. J Med Case Reports. 2011; 5: 426. Published online 2011 September 2. doi: 10.1186/1752-1947-5-426. PMCID: PMC3179757
Meenal. C., Hiremath P. B., Nidhi Bansal, Subhasini, Premaleela, Rajesh, Ravikannan.
[1.] Professor & Head, Department of Obstetrics and Gynaecology, SVMCH & RC, Ariyur, Pondicherry.
[2.] Assistant Professor, Department of Obstetrics and Gynaecology, SVMCH & RC, Ariyur, Pondicherry.
[3.] Assistant Professor, Department of Obstetrics and Gynaecology, SVMCH & RC, Ariyur, Pondicherry.
[4.] Assistant Professor, Department of Obstetrics and Gynaecology, SVMCH & RC, Ariyur, Pondicherry.
[5.] Professor, Department of Obstetrics and Gynaecology, SVMCH & RC, Ariyur, Pondicherry.
[6.] Assistant Professor, Department of Paediatrics, SVMCH & RC, Ariyur, Pondicherry.
[7.] Assistant Professor, Department of Paediatrics, SVMCH & RC, Ariyur, Pondicherry.
Dr. Hiremath P.B.
Dept. of O&G SVMCH & RC, Ariyur, Pondicherry.
E-mail: firstname.lastname@example.org, Ph:00917639672385
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|Title Annotation:||CASE REPORT|
|Author:||C., Meenal.; B., Hiremath P.; Bansal, Nidhi; Subhasini; Premaleela; Rajesh; Ravikannan|
|Publication:||Journal of Evolution of Medical and Dental Sciences|
|Article Type:||Clinical report|
|Date:||Jan 7, 2013|
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