Mermaid Syndrome scientifically known as Sirenomelia recently caused sensations in the Ghanaian media when an image of a baby born with the defect was leaked to the media. As is typical within our culture, anything out of the ordinary gets stigmatised. A few took to social media to condemn the act and as one rightly pointed out, how did the image of the newborn get out in the first place. Comes down to ethical issues within the healthcare sector and our society in general but that is a topic for another day.
Sirenomelia is a rare congenital condition where the lower limbs of a foetus are fused together during the early stages of development in the womb causing the mermaid like appearance at birth. The condition affects about 1 in 100, 000 pregnancies worldwide with a higher incidence in the male child compared to females (ratio of 3:1). In most cases, sirenomelia is fatal due to development of secondary conditions such as absent genitalia, renal problems and digestive defects. Sirenomelia can be detected by about 13 weeks of pregnancy using ultrasound with about 22% of mothers with children born with the syndrome having diabetes. This has led to many considering diabetes to be a susceptibility factor to giving birth to a child with Sirenomelia.
The actual scientific cause of the mermaid syndrome is unknown and whiles genetics is thought to play a role this is yet to be confirmed. There are currently two main theories about the cause; vascular steal hypothesis and defective blastogenesis hypothesis.
The vascular steal hypothesis
During the early stage of a baby’s development when the embryo first starts to form, three main layers of cells are made; Ectoderm on the outside, mesoderm in the middle and endoderm on the inside. Each of these layers is responsible for further developments of the various body parts. The middle layer, the mesoderm (specifically the lateral mesoderm) is responsible for forming the genital ducts, bones of the limbs and other parts in the lateral section.
According to the vascular steal hypothesis, fusion of the limbs is a result of the abnormal development of the umbilical cord blood vessels where instead of two arteries and a vein you have one of each leading to reduced blood flow and nutrient supply to the lateral mesoderm. This leads to the failure of the midline structures and subsequent abnormal formation of the lower limbs.
The defective blastogenesis hypothesis
In the defective blastogenesis hypothesis, the primary defect in development of the lateral mesoderm is attributed to an external agent or chemical which affects the normal development of the foetus during the formation of the three cell layers (ectoderm, mesoderm, endoderm). This stage of the embryonic development when the three layers are formed is known as gastrulation and chemical interferences at this stage can lead to malformation of the mesoderm and subsequently the abnormal development of various structures.
The way forward
As is common on this portal, we say Do Not Stigmatise. The case may be new not only in the Ghanaian society but others as well. Although the condition is rare, at present, there are about 300 published cases of the mermaid syndrome with a handful of survivors. It is believed the term mermaid as we see depicted in cartoon and movies today is an adaptation of this medical condition and you can see some mermaid syndrome babies on display in some museums around the world.
Who knows how long this child in particular will live. Although mostly fatal, some have survived in mild cases where secondary organ damage is not extensive and can be corrected. We wish the family all the best.