Ablepharon macrostomia syndrome - congenital condition

 

AMS is the short form of Ablepharon macrostomia syndrome. It can be generally defined as a rare genetic disorder which can be characterized by ablepharon or microblepharon and also it along with macrostomia. The main features and characteristics of this Ablepharon macrostomia syndrome majorly includes the unusual appearance of the face and skin and in some rare cases it involves viscera or internal organs.  Because, AMS syndrome typically comes under the group of diseases which is commonly known as ectodermal dysplasias as it mainly involves abnormalities in some parts of your body like skin, sweat glands, hair, nails, and/or teeth.

What makes this syndrome different from other ectodermal dysplasias because it does not involve all the characteristics that are called it is considered as genuine malformation syndrome. More of that, Ablepharon macrostomia syndrome is typically caused by TWIST2 gene mutations with autosomal dominant genes which makes its occurrence suddenly sporadically among its patients. But mutated TWIST2 gene is not only the cause for ASM  but it can also cause Barber Say syndrome and Setleis syndrome. So, it is very important to get tested before you make a conclusion.

Causes

One of the root and main causes of this AMS syndrome is the unusual and abnormal mutation of TWIST2 gene. Hence, the effects of this syndrome happen spontaneously, people who are affected do not inherit this mutated gene from both of the parents but one of the biological parents who has the mutated TWIST2 gene with an autosomal dominant pattern. Usually, the affected person gets the abnormal gene from the  dominant parent.

This health condition is generally a dominant genetic disorder where one of the parents inherits a non-working copy of the gene also called it as silent carrier of the disease. Typically, the risk is equal for both male and females and the probability of passing this mutate non working gene to your offspring is 50 % chance in every pregnancy.

Signs & symptoms of Ablepharon-Macrostomia Syndrome (AMS)?

Signs and symptoms of AMS Syndrome will show up its effects in anytime whenever in your life which includes:

• Low-set ears with attached earlobes.

• Camptodactyly which means - fusion of fingers.

• Camptodactyly which means - distortion of fingers.

• Bulging cheeks.

• Small or no nipples.

• Redundant and wrinkled skin.

• Sparse or no hair.

• Genital malformations.

• Not fully developed or without eyelids, eyebrows, and eyelashes during birth.

• Wide mouth.

Further complications are:

• Ectropion - abnormal turning of upper or lower eyelids in your eyes.

• Lagophthalmos - sudden exposure of inner mucous membranes which makes you difficult for eyes to shut properly

• Photophobia - sensitivity to light.

• Syndactyly - unusual or abnormal looseness in your skin over the hands.

• Alacrimia - which makes you hold your tears not producing.

• Nystagmus - eye movements like involuntary and repeated eye movements.

• Strabismus - inward unequal or abnormal deviation of the eyes.

• Partial or complete separation of the retina.

• Detached retina.

• Vision loss.

Infants who are affected by this syndrome may show other signs like:

• Wide nasal bridge.

• Small chin.

• Low set ears with attached earlobes.

• Flared nostrils.

• Impaired hearing.

• Philtrum  which means long groove between the nose and lips area.

• Alae nasi which means thick-flared edges of nostrils.

• Cheek puffs  or pads like facial appearance because of bulging cheeks which are considered as superolateral in the corners of the mouth.

• Absence of zygomatic arches especially in the skull.

• Lanugo which means Absence of the soft, downy hair.

• Redundant and wrinkled skin.

• Sparse scalp hair.

• Absent nipples.

• Abdominal hernia.

• Underdeveloped or unusual genitalia formation.

• And lastly for males - small penis and for females - small labia minora.

Diagnosis

Usually the diagnosis of this AMS syndrome can be detected from birth via clinical evaluation, family medical history, and also by doing physical examination through testing and sampling. Through regular testing, it is very hard to find the differences between BSS and AMS, so molecular genetic testing for mutated TWIST2 gene is necessary.

Other than the molecular testing here is a list of other testings which can be conducted to diagnose the AMS cases:

• Computerized tomography (CT) scanning -  which helps to detect skeletal abnormalities such as maxillary and mandibular prominences and also absence of the zygomatic arch.

• And eye testing helps to determine the overall development and some other damages because of abnormalities of eyelids.

Treatment

The core treatment is majorly focused on easing the symptoms. This Ablepharon macrostomia syndrome will directly hit off the healthy eyelids so that your medical providers suggest treatments like corrective and reconstructive surgery. These surgeries will focus at preserving and reducing any of the vision complications like corneal clouding which can be commonly witnessed during the neonatal period.

Among all symptoms of AMS syndrome, the most complicated one is lagophthalmos which usually causes you not to close your eyelids properly. And followed by a surgery will be done to manage the symptoms like ectropion and underdevelopment of eyelids to transfer the skin flaps to the lid region.

And some other corrective surgeries will be done to correct the abnormalities of fingers, skin and ears. By providing some other supportive therapy like lubricant eye drops early on which might be improve the symptoms of eye dryness which includes:

• Local flaps correction.

• Face-lift procedures.

• Forehead lifting.

• Botox injections.

• Fat grafting.

• Orthognathic surgery.

• Nasal reconstruction with rib cartilage grafts.

The above procedures are not broadly recommended to all affected people, particularly to young ones which may risk the growth of craniofacial.

Genetic counseling will be suggested for patients and also to their families to develop an understanding of the genetic inheritance and also medical history of the family with AMS syndrome. Psychosocial support must be needed for patients and also for guardians and other family members for overall healthcare.

Frequently Asked Questions

Q1. What is the life expectancy of someone with Ablepharon macrostomia syndrome?

Ans: Physical appearance cannot be corrected to the "norm" but the life expectancy of patients diagnosed with AMS is normal.

Q2. What causes Ablepharon?

Ans: Ablepharon macrostomia syndrome is caused by genetic changes in the TWIST2 gene.

Q3. Is Ablepharon macrostomia syndrome hereditary?

Ans: Ablepharon macrostomia syndrome is caused by genetic changes in the TWIST2 gene. Inheritance is autosomal dominant, but most cases are sporadic (when there are no other cases in the family).

Q4. How rare is ablepharon macrostomia syndrome?

Ans: AMS is a rare condition characterized by absent or extremely short eyelids and a large fish-like mouth, only 20 cases were reported.