Micrognathia: Definition, Causes, Symptoms, Treatments and Associated Syndromes

Also called micrognathism, strawberry chin, hypognathous, or hypogonadism, it is a condition in which the jaw is undersized.

It is also sometimes called ‘ jaw hypoplasia. ‘

It is common in babies but usually self-corrects during growth due to increased jaw size. It can cause abnormal tooth alignment, and in severe cases, it can make feeding difficult.

In both adults and children, intubation can also be difficult, either during anesthesia or in emergencies.

Causes of micrognathia

Although it is not always pathological, it can present as a congenital disability in multiple syndromes that include:

Catel-Manzke syndrome

Catel-Manzke syndrome is a rare genetic disorder characterized by distinctive abnormalities of the index fingers, the classic features of Pierre Robin syndrome, occasionally with additional physical findings.

Pierre Robin syndrome refers to a sequence of abnormalities that can occur as a distinct syndrome or as part of another underlying disorder.


Pierre Robin syndrome is characterized by a tiny jaw (micrognathia), downward displacement or retraction of the tongue (glossoptosis), and incomplete closure of the roof of the mouth (cleft palate). It is also related to hypermobility syndrome.

Bloom’s syndrome

Bloom syndrome (often abbreviated as SB in the literature), also known as Bloom-Torre-Machacek syndrome, is a rare autosomal recessive disorder characterized by short stature, predisposition to cancer development, and genomic instability.

Bloom syndrome is caused by mutations in the BLM gene that lead to mutated DNA helicase protein formation.

The cells of a person with Bloom syndrome exhibit surprising genomic instability that includes excessive crossovers between homologous chromosomes and sister chromatid exchanges.

The disease was first discovered and described by New York dermatologist Dr. David Bloom in 1954.

Síndrome de Coffin-Lowry

Coffin-Lowry syndrome is a genetic disorder that is linked to the dominant X chromosome and causes severe mental problems sometimes associated with growth abnormalities, heart abnormalities, kyphoscoliosis, as well as hearing and visual abnormalities.

Congenital rubella syndrome

Congenital rubella syndrome (CRS) can occur in a pregnant woman’s developing fetus who contracts rubella, usually in the first trimester.

If the infection occurs 0-28 days before conception, the baby has a 43% risk of being affected. If the condition occurs 0 to 12 weeks after birth, the risk increases to 51%.

If the infection occurs 13-26 weeks after conception, the risk is 23% of babies affected by the disease. Babies are generally not affected if rubella is contracted during the third trimester or between 26 and 40 weeks after conception.

Problems rarely occur when the mother contracts rubella after 20 weeks of gestation and continues to shed the virus after birth.

Cri du Chat syndrome

Cri du Chat syndrome, also known as chromosome 5p deletion syndrome, 5p syndrome (pronounced “Five P Minus”), or Lejeune syndrome, is a rare genetic disorder due to chromosome deletion on chromosome 5.

Its name is a French term (cry or call the cat) referring to the characteristic cat cry of affected children. The condition affects about 1 in 50,000 live births across all ethnicities and is more common in women at a 4: 3 ratio.

Digeorge syndrome

DiGeorge syndrome, also known as 22q11.2 deletion syndrome, is caused by the deletion of a small segment of chromosome 22.

Although symptoms can be variable, they often include congenital heart problems, specific facial features, frequent infections, developmental delay, learning disabilities, and a cleft palate.

Associated conditions include kidney problems, hearing loss, and autoimmune disorders such as rheumatoid arthritis or Graves’ disease.

DiGeorge syndrome is typically due to the deletion of 30 to 40 genes in the middle of chromosome 22 at a location known as 22q11.2.

About 90% of cases occur due to a new mutation during early development, while 10% are inherited from a person’s parents.

It is autosomal dominant, which means that only one affected chromosome is needed for the condition to occur. The diagnosis is suspected to be based on symptoms and confirmed by genetic testing.

Although there is no cure, treatment can improve symptoms. This often includes a multidisciplinary approach with efforts to improve the function of the potentially numerous organ systems involved.

Long-term results depend on the symptoms present and the severity of the heart and immune system problems. With treatment, life expectancy can be average.

DiGeorge syndrome occurs in about 1 in 4,000 people. The syndrome was first described in 1968 by the American physician Angelo DiGeorge. In late 1981, the underlying genetic characteristics were determined.

Ehlers-Danlos syndromes

Ehlers-Danlos syndromes (EDS) are a group of inherited connective tissue disorders. Symptoms can include loose joints, elastic skin, and abnormal scarring.

Complications include aortic dissection, joint dislocations, scoliosis, chronic pain, or early osteoarthritis.

Ehlers-Danlos syndromes are due to a mutation in one of more than a dozen different genes. The specific gene affected determines the specific Ehlers-Danlos syndrome.

Some cases result from a new mutation that occurs during early development, while others are inherited in an autosomal dominant or recessive manner. This results in defects in the structure or processing of collagen.

The diagnosis can be confirmed with genetic testing or a skin biopsy. People can be misdiagnosed with hypochondriasis, depression, or chronic fatigue syndrome.

There is no known cure. Treatment is supportive. Physical therapy and braces can help strengthen your muscles and joints.

While some disorders result in an average life expectancy, those that affect the blood vessels generally result in a shorter life expectancy.

Ehlers-Danlos syndromes affect approximately 1 in 5,000 people worldwide. The prognosis depends on the specific disorder.

Hippocrates first described excess mobility in 400 BC. The syndromes are named after two physicians, Edvard Ehlers from Denmark and Henri-Alexandre Danlos from France, who told them in the early 20th century.

The spectrum of fetal alcoholism

Fetal Alcohol Spectrum Disorders (FASDs) are a group of conditions that manage to pass in an individual whose mother drank alcohol while pregnant.

Problems can include an abnormal appearance, short height, low body weight, small head size, poor coordination, poor intelligence, behavior problems, and problems with hearing or seeing.

Those affected are more likely to have problems in school, legal problems, engage in high-risk behaviors, and have difficulties with alcohol or other drugs.

The most severe form of the disease is fetal alcohol syndrome (FAS).

Some accept only fetal alcohol syndrome as a diagnosis, considering that the evidence is inconclusive regarding other types.

Surveys conducted in the United States have revealed that about 10% of pregnant women drank alcohol in the past month and 20% to 30% drank during their pregnancy.

About 4.7% of American women who are pregnant are alcoholics. The risk of problems depends on the amount consumed, frequency of consumption, and when alcohol is consumed during pregnancy.

Other risk factors include an older mother, smoking, and a poor diet. There is no known safe amount or safe time to drink during pregnancy.

While drinking small amounts of alcohol does not cause facial abnormalities, it can cause behavior problems. Alcohol crosses the blood-brain barrier and directly and indirectly affects a developing baby. The diagnosis is based on the signs and symptoms in the person.

Fetal alcohol spectrum disorders can be avoided by avoiding alcohol. For this reason, medical authorities recommend not consuming alcohol during pregnancy or when trying to get pregnant. While the condition is permanent, treatment can improve results.

Interventions may include parent-child interaction therapy, efforts to modify children’s behavior, and possibly medications.

Fetal alcohol spectrum disorders affect between 2% and 5% of people in the United States and Western Europe. Fetal alcohol syndrome is believed to occur in between 0.2 and 9 per 1,000 live births in the United States.

In South Africa, some populations have rates as high as 9%. The adverse effects of alcohol during pregnancy have been described since ancient times.

The lifetime cost per child with fetal alcohol syndrome was $ 2,000,000 in 2002. The term fetal alcohol syndrome was first used in 1973.

Hallermann-Streiff syndrome is a congenital disorder that affects growth, skull development, hair growth, and tooth development. There are fewer than 200 people with the syndrome worldwide.

One organization supporting people with Hallermann-Streiff syndrome is “Schattenkinder eV,” based in Germany.

Patients with this syndrome are shorter than the average person and may not develop hair in many places, including the facial, leg, and pubic areas.

Patients also have eye problems, including reduced eye size, bilateral cataracts, and glaucoma. The syndrome can be associated with sleep apnea.

The physical characteristics of the syndrome can cause difficult intubation by medical professionals.

The genetic cause of Hallermann-Streiff syndrome has not been conclusively determined. It is most likely due to a de novo mutation and may be associated with the GJA1 gene.

Hemifacial microsomia (as part of Goldenhar syndrome)

Hemifacial microsomia (HFM) is a congenital disorder that affects the development of the lower half of the face, usually the ears, mouth, and jaw. It usually occurs on one side of the beginning, but both sides are sometimes affected.

If it is severe, it can cause breathing difficulties due to obstruction of the windpipe; sometimes, it even requires a tracheostomy.

With an incidence in 1: 3500 to 1: 4500, it is the second most common congenital disability in the face, after cleft lip and palate. Hemifacial microsomia shares many similarities with Treacher Collins syndrome.

Goldenhar syndrome can be considered a particularly severe form of hemifacial microsomia, in which extracranial abnormalities are present to some extent.

Some of the internal organs (especially the heart, kidneys, and lungs) may be underdeveloped or, in some cases, even absent altogether.

The affected organs are typically on the same side as the fake facial features, but bilateral involvement occurs in approximately 10% of cases. Spinal deformities such as scoliosis can also be seen in Goldenhar syndrome.

Juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA), also known as juvenile rheumatoid arthritis, is the most common form of arthritis in children and adolescents.

“Juvenile” in this context refers to an onset before the age of 16, “idiopathic” refers to a condition with no definite cause, and “arthritis” is inflammation of the synovium of a joint.

Juvenile idiopathic arthritis is an inflammatory, non-infectious, autoimmune joint disease lasting more than six weeks in children younger than 16.

The disease commonly occurs in children between 1 and 6 but can develop up to 15 years. It is a subset of arthritis seen in childhood, which can be transient and self-limited or chronic.

It differs significantly from arthritis commonly seen in adults (osteoarthritis, rheumatoid arthritis) and other types of arthritis that can occur in childhood and are chronic conditions (for example, psoriatic arthritis and ankylosing spondylitis).

The etiopathogenesis is similar to rheumatoid arthritis but with less marked cartilage erosion, joint instability, and absence of rheumatoid factor.

Juvenile idiopathic arthritis affects about one in 1,000 children in a given year, and about one in 10,000 has a more severe form.

Marfan syndrome

Marfan syndrome (MFS) is a genetic disorder of the connective tissue. The degree of affectation of people varies. People with Marfan syndrome often have flexible joints and scoliosis.

The most serious complications involve the heart and aorta with an increased risk of mitral valve prolapse and aortic aneurysm. Other commonly affected areas include the lungs, eyes, bones, and the covering of the spinal cord.

Marfan syndrome is an autosomal dominant disorder. About 75% of the time, the condition is inherited from a parent, while 25% of the time, it is a new mutation.

It involves a mutation in the gene that produces fibrillin, resulting in abnormal connective tissue. The diagnosis is often based on the Ghent criteria.

There is no known cure for Marfan syndrome. Many people have an average life expectancy with proper treatment.

Treatment often includes beta-blockers, such as propranolol or atenolol, or if not tolerated, calcium channel blockers or angiotensin-converting enzyme inhibitors (ACE inhibitors).

Surgery may be required to repair the aorta or replace a heart valve. It is recommended to avoid strenuous exercise.

About one in 5,000 to 10,000 people has Marfan syndrome. It occurs equally in men and women.

The rates are similar between races and in different regions of the world. It is named after Antoine Marfan, a French pediatrician who first described the condition in 1896.

Noonan syndrome

Noonan syndrome (SN) is a relatively common autosomal dominant congenital disorder named after Jacqueline Noonan, a pediatric cardiologist.

It used to be referred to as a male version of Turner syndrome; however, the genetic causes of Noonan syndrome are different from Turner syndrome, and both men and women are affected.

The main features include:

  • Congenital heart defect (typically pulmonary valve stenosis with dysplastic pulmonary valve also atrial septal defect and hypertrophic cardiomyopathy).
  • Short stature.
  • Learning problems.
  • Pectus excavatum.
  • Alteration of blood clotting.
  • Typical configuration of facial features, including a webbed neck and a flat nasal bridge.

Noonan syndrome is a Rasopathy (developmental syndromes caused by germline mutations) and is one of several disorders caused by a disruption of the RAS-MAPK signaling pathway.

About 1 in 1,000 and 1 in 2,500 children worldwide are believed to be born with Noonan syndrome.

It is one of the most common genetic syndromes associated with congenital heart disease, similar in frequency to Down syndrome.

However, the range and severity of the features can vary significantly in patients with Noonan syndrome. Therefore, the syndrome is not always identified at an early age.

Pierre Robin syndrome

Pierre Robin syndrome (abbreviated as PRS, also known as Pierre Robin sequence, Pierre Robin malformation, Pierre Robin anomaly, or Pierre Robin anomaly) is a congenital condition of facial abnormalities in humans.

Pierre Robin syndrome is a sequence, that is, a chain of specific developmental malformations, one involving the following.

The three main features are:

  • Cleft palate.
  • Retrognathia (abnormal position of the jaw or mandible).
  • Glossoptosis (airway obstruction caused by the backward displacement of the base of the tongue).

A genetic cause of Pierre Robin syndrome was recently identified. The Pierre Robin sequence can be caused by congenital abnormalities on chromosomes 2, 11, or 17.

Pierre Robin syndrome is characterized by an unusually small jaw (micrognathia), posterior displacement or retraction of the tongue (glossoptosis), and upper airway obstruction.

Incomplete closure of the roof of the mouth (cleft palate) is present in most patients and is commonly U-shaped.

Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a genetic disorder due to the loss of function of specific genes. In newborns, symptoms include weak muscles, poor diet, and slow development.

Often the forehead is narrow, the hands and feet small, the height is short, the skin is light in color, and those affected are unable to have children.

A similar mechanism occurs in Angelman syndrome, except a defective chromosome 15 from the mother or two copies from the father.

There is no cure for Prader-Willi syndrome. However, treatment can improve results, especially if done early. In newborns, feeding difficulties may be compatible with feeding tubes.

Strict food supervision is generally required from three in combination with an exercise program. The therapy with growth hormone also improves the results.

Counseling and medicine can help with some behavior problems. Group homes are often necessary for adulthood.

Síndrome de Silver-Russell

Silver-Russell syndrome (SSR), also called Silver-Russell dwarfism or Russell-Silver syndrome (RSS), is a growth disorder that occurs in approximately 1 / 50,000 to 1 / 100,000 births.

In the United States, it is generally known as Russell-Silver syndrome and Silver-Russell syndrome elsewhere. It is one of the 200 types of dwarfism and one of the five types of primordial dwarfism and is one of the few firms that is considered treatable in some cases.

There is no statistical significance of the syndrome that occurs preferentially in men or women.

Seckel syndrome

Seckel syndrome or microcephalic primordial dwarfism (also known as bird-head dwarfism, Harper syndrome, Virchow-Seckel dwarfism, and Seckel bird-head dwarf) is a sporadic congenital nanosomal disorder.

The inheritance is autosomal recessive. It is characterized by intrauterine growth retardation and postnatal dwarfism. It has a small head, a narrow bird-like face with a beak-shaped nose, large eyes with downward sloping palpebral fissures, and a delayed jaw and intellectual disability.

A mouse model has been developed. This mouse model is characterized by severe ATR protein deficiency. These mice suffer high levels of replicative stress and DNA damage.

Adult Seckel mice show accelerated aging. These findings are consistent with the DNA damage theory of aging.

Smith-Lemli-Opitz syndrome

Smith-Lemli-Opitz syndrome (also SLOS or 7-dehydrocholesterol reductase deficiency) is an innate error in cholesterol synthesis.

An autosomal recessive multiple malformation syndrome is caused by a mutation in the enzyme 7-Dehydrocholesterol reductase or DHCR7. It causes a broad spectrum of effects, ranging from mild intellectual disability and behavioral problems to life-threatening malformations.

Treacher Collins syndrome

Treacher Collins syndrome (TCS) is a genetic disorder characterized by deformities of the ears, eyes, cheekbones, and chin. However, the degree to which a person is affected can range from mild to severe.

Complications can include breathing problems, vision problems, a cleft palate, and hearing loss. Those affected generally have average intelligence.

Treacher Collins syndrome is generally autosomal dominant. More than half the time, it occurs due to a new mutation rather than being inherited from a person’s parents.

The gene involved can include TCOF1, POLR1C, or POLR1D. The diagnosis is usually suspected based on symptoms and x-rays and possibly confirmed by genetic testing.

Treacher Collins syndrome is not curable. With reconstructive surgery, hearing aids, speech therapy, and other assistive devices, symptoms can be managed. Life expectancy is generally average.

Treacher Collins syndrome occurs in about one in every 50,000 people. The syndrome is named after Edward Treacher Collins, an English surgeon and ophthalmologist, who described its essential features in 1900.

Trisomy 13 (Patau syndrome)

Patau syndrome is a syndrome caused by a chromosomal abnormality, in which some or all of the body’s cells contain extra genetic material from chromosome 13. The additional genetic material disrupts normal development, causing multiple complex organ defects.

This can occur either because each cell contains an extra complete copy of chromosome 13 (a disorder known as trisomy 13 or trisomy D) or because each cell contains an additional partial reproduction of the chromosome (i.e., Robertsonian translocation) or due to a mosaic of the Patau syndrome.

Total trisomy 13 is caused by nondisjunction of chromosomes during meiosis (the mosaic shape is caused by nondisjunction during mitosis).

Like all nondisjunction conditions (such as Down syndrome and Edwards syndrome), the risk of this syndrome in offspring increases with maternal age during pregnancy, averaging approximately 31 years.

Patau syndrome affects between 1 in 10,000 and 1 in 21,700 live births.


Progeria, also known as Hutchinson-Gilford syndrome, is a sporadic and progressive genetic disorder that causes children to increase, beginning in their first two years of life.

Signs and symptoms begin to appear during the first year, such as slow growth and hair loss. Heart problems or strokes are the ultimate cause of death for most children with Progeria.

The average life expectancy of a child with Progeria is about 13 years. Some with the disease may die younger, and others may live longer, even 20 years.

There is no cure for Progeria, but ongoing research shows some promise for treatment.

Trisomy 18 (Edwards syndrome)

Edwards syndrome, also known as trisomy 18, is a genetic disorder caused by the presence of all or part of the third copy of chromosome 18. Many parts of the body are affected.

Babies are often born small and have heart defects. Other features include a small head, small jaw, clenched fists with overlapping fingers, and severe intellectual disability.

Most cases of Edwards syndrome occur due to problems during the formation of reproductive cells or during early development. The disease rate increases with the age of the mother.

Rarely can cases be inherited from a person’s parents. Occasionally, not all cells have the extra chromosome, known as mosaic trisomy, and symptoms in these cases may be less severe.

Ultrasound can increase suspicion of the condition, confirmed by amniocentesis.

Treatment is supportive. After having a child with the condition, the risk of having a second is typically around one percent. It is the second most common condition due to the third chromosome at birth, after Down syndrome.

Edwards syndrome occurs in one in every 5,000 live births. Some studies suggest that more babies who survive delivery are women.

Many of those affected die before birth. Survival beyond one year of life is around 5-10%. It is named after John Hilton Edwards, who first described the syndrome in 1960.

Wolf-Hirschhorn syndrome

Wolf-Hirschhorn syndrome (SWH), also known as Dillan 4p syndrome chromosomal deletion, Pitt-Rogers-Danks syndrome (SPRD), or Pitt syndrome, is a chromosome deletion syndrome resulting from a partial deletion of the short arm of chromosome 4 (del (4p16.3)).

Features include a distinctive craniofacial phenotype and intellectual disability.

X0 syndrome (Turner syndrome)

Turner syndrome (TS), also known as 45, X or 45, X0, is a condition in which a woman partially or completely misses an X chromosome. Signs and symptoms vary among those affected.

Often at birth, a short, webbed neck, open ears, a low hairline at the back of the neck, short stature, and swollen hands and feet are seen.

They usually develop menstrual periods and breasts only with hormonal treatment and cannot have children without reproductive technology. Heart defects, diabetes, and low thyroid hormone occur more frequently.

Most people with Turner syndrome have average intelligence. Many, however, have problems with spatial visualization that may be necessary for math. Vision and hearing problems occur more often.

Turner syndrome is generally not inherited from a person’s parents. There are no known environmental risks, and the mother’s age does not play a role.

Turner syndrome is caused by a chromosomal abnormality in which all or part of one of the X chromosomes is missing or altered. While most people have 46 chromosomes, people with Turner syndrome generally have 45.

The chromosomal abnormality may be present only in some cells, in which case it is known as Turner syndrome with mosaicism.

The symptoms are generally minor in these cases, and possibly none are present. The diagnosis is based on physical signs and genetic tests.

There is no known cure for Turner syndrome. Treatment, however, can help with symptoms. Human growth hormone injections during childhood can increase adult height.

Estrogen replacement therapy can promote breast and hip development. Medical attention is often required to manage other health problems associated with Turner syndrome.

Turner syndrome occurs between one in 2000 and one in 5000 women at birth. All world regions and cultures are affected equally.

People with Turner syndrome have a shorter life expectancy, mainly due to heart problems and diabetes. Henry Turner first described the condition in 1938. In 1964, it was determined to be due to a chromosomal abnormality.


The doctor may recommend orthognathic surgery (reconstructive) or orthodontic devices.