What is Nager Syndrome? A Rarely Seen Hereditary Disease
Nager syndrome; It is a rare hereditary disease that was first introduced to the medical literature by Nager and De Reynier in 1948.
It is a congenital condition that affects the bones and tissues in the face. It also appears to affect the arms and hands, and sometimes the legs and feet, while in early pregnancy the cheekbones, eye sockets, and chin may not develop properly. This condition causes a characteristic appearance with downward-slanting eyes and a small chin. Nager syndrome is similar to Treacher-Collins syndrome, with additional problems in the arms and hands and often associated with a cleft palate.
Nager syndrome is distinguished from other forms of acrofacial dysostosis by limb abnormalities, primarily on the thumb side of the hand and forearm, including underdevelopment or absence of the thumb and radius bones and abnormal bone fusion in the forearms. Fingers and feet are usually normal. Intelligence is usually unaffected. Nager syndrome is typically inherited in an autosomal dominant pattern and is caused by changes (mutations) in the SF3B4 gene.
Although an individual with Nager syndrome can transmit the condition to their children, many cases occur randomly as a new gene change in the family. This syndrome is typically inherited in an autosomal dominant pattern and is caused by changes in a gene called SF3B4.
What causes Nager syndrome?
Although doctors suspect that Nager syndrome may be a genetic condition caused by a change in a particular gene, the specific genes that cause the disease have not yet been identified.
The gene suspected to be involved in Nager syndrome alters the development of the first and second pharyngeal arches, the starting points in head and neck development, in early pregnancy. Pharyngeal arches are structures on both sides of the head and neck that develop into facial and neck structures. In particular, the first and second pharyngeal arches form the nerves and muscles necessary for expressing facial expressions and chewing, as well as structures within the outer ear and middle ear.
What are the symptoms of Nager syndrome?
Children with Nager syndrome have a characteristic appearance due to problems in the formation of the cheekbones, chin and eye sockets. If the jaw is too small and/or underdeveloped, breathing difficulties may occur soon after birth. Jaw problems can also cause feeding difficulties.
In children with Nager syndrome, the ears are often either absent or very small. If the internal structures of the ear are also underdeveloped, this can lead to hearing impairment.
Arms and hands are also affected in Nager syndrome. Often, the elbow joint is stiff, so bending the arm can be difficult. The radius bone in the arm may be missing or underdeveloped, causing the hand to bend toward the body, that is, deviate radially. This can affect all structures on the radial side of the upper extremity, including bones and soft tissues (muscles, tendons, joints, nerves and blood vessels).
It is known that children with Nager syndrome also have problems in their hands. Most commonly, the thumbs of both hands are underdeveloped or absent, which can lead to problems with grip and fine movement. Other fingers may be abnormally curved, stiff, and sometimes syndactyly, or webbed. In some children, their legs and feet are similarly affected.
Rarely, it has been observed that other structures in the body are also affected.
Affected Populations
Although there is no evidence that Nager syndrome affects men or women more, it is known to affect men and women in equal numbers. The exact incidence and prevalence in the general population is unknown. However, many cases are misdiagnosed or undiagnosed, making it difficult to determine the true frequency in the general population. More than 100 cases have been reported in the medical literature. Nager syndrome is the most common form of acrofacial dysostosis.
How is Nager syndrome diagnosed?
Since children with Nager syndrome have a characteristic appearance, we can say that there is no need for specific diagnostic tests. Experts note that while imaging scans such as x-rays, CT or MRI may be recommended to monitor bone growth before, during and after treatment, imaging may also be required to examine the internal structures of the ear, as well as hearing tests to diagnose hearing loss.
How is Nager syndrome treated?
Because Nager syndrome can affect various areas of the head and face, treatment is best provided in a specialist center where a multidisciplinary team approach can be applied. The multidisciplinary team usually consists of craniofacial (skull and face) surgeons, maxillofacial surgeons, ear, nose and throat (ENT) surgeons, hand surgeons, plastic surgeons, audiologists (hearing specialists), dentists and orthodontists, geneticists, and speech and language therapists.
Initially, stabilizing a child's breathing problems will require treatment. For some children, these are so severe that a tracheostomy, an artificial opening into the windpipe, may be needed to allow them to breathe. Some children may only need breathing support at night.
If the thumb is present but weak, surgery may be performed to stabilize any unstable joints and strengthen the thumb by taking a tendon or muscle from another part of the hand. If the thumb is absent or immobile, the index finger on that hand can be moved to the thumb position (pollicization). If any toe webs are causing a problem with function, they can be corrected with a series of surgeries during childhood. Later in childhood, the underdeveloped jaw may require treatment. This is a long-term treatment process, but it is known to have good results for most children.
Ear reconstruction can also be done later in childhood, either by creating a new ear modeled on the other ear or, if neither is available, by creating the parents' ears. Ear reconstruction is a procedure that only improves the appearance of the ear but has no effect on its function. Hearing impaired children may need support with hearing aids or cochlear implants and speech and language therapy.
Because bone continues to grow during childhood and adolescence, more surgery may be required to reconstruct the facial shape.
Related Disorders That May Be Similar to Nager Syndrome
Symptoms of the following disorders may be similar to those of Nager syndrome. Comparisons may be useful for differential diagnosis.
- Postaxial acrofacial dysostosis Miller syndrome, also known as Miller syndrome, is a rare genetic disorder characterized by craniofacial malformations that occur with arm, hand, and/or foot abnormalities usually involving the post-axial (little finger or little toe) side. Craniofacial abnormalities underdevelopment of the cheekbones (malar hypoplasia); an abnormally small lower jaw (micrognathia); incomplete closure of the roof of the mouth (cleft palate); small, protruding, “cup-shaped” ears; and/or absence of tissue in the lower eyelids (colobomas). Limb abnormalities may include incomplete development, webbing (syndactyly), and/or occlusion or absence of certain fingers and/or toes; and/or improper development and/or abnormal fusion of the bones in the forearms (radioulnar synostosis), causing the forearms to appear unusually short. In some cases, additional physical abnormalities may occur. Intelligence is not affected. Miller syndrome is inherited as an autosomal recessive trait caused by mutations in genes.
- Treacher Collins syndrome (TCS)It is a rare genetic disorder characterized by marked abnormalities in the head and face region resulting from underdevelopment (hypoplasia) of certain facial structures, including the jaw, cheekbones, and nearby structures (zygomatic complex), and differs from Nager syndrome in that the limbs are usually normal. Craniofacial abnormalities tend to involve the cheekbones, jaws, mouth, ears, and/or eyes. In addition to various facial abnormalities, affected individuals may have malformations of the outer ears and middle ear structures and eye (ocular) abnormalities, including abnormal downward tilt into the opening between the upper and lower eyelids (palpebral fissures). Affected individuals may develop hearing loss and respiratory (breathing) difficulties. Moreover, brain and behavioral anomalies such as Microcephaly and psychomotor delay have also sometimes been reported as part of the condition. The specific physical characteristics and symptoms associated with TCS can vary greatly from person to person. While some people may have mild symptoms and go undiagnosed, others may develop serious, life-threatening respiratory complications. TCS is known to be caused by a mutation.
- Also known as Rodriguez's acrofacial dysostosis syndrome Rodriguez syndromeIt is a very rare disease. There is significant overlap in both craniofacial and extremity abnormalities in Nager and Rodriguez syndromes. Some researchers believe that certain cases of Rodriguez syndrome may represent a more severe expression of Nager syndrome. In addition to the physical findings commonly found in Nager syndrome, individuals with Rodriguez syndrome may also have underdevelopment of the fibula, the outer and narrower long bone of the leg (fibular hypoplasia), underdevelopment of the eleven ribs, shoulder and pelvic girdle, and underdevelopment of the heart. , central nervous system and urogenital abnormalities. Babies with Rodriguez syndrome are often stillborn or die in the immediate neonatal period due to serious airway problems.
- As a finding among several rare disorders Weyers acrofacial dysostosis, Catania acrofacial dysostosis and Palagonia acrofacial dysostosis. Other disorders that may have symptoms or physical findings that overlap with Nager syndrome include ophthalmo-acromelic syndrome, Pallister-Hall syndrome, Guion-Almeida type of mandibulofacial dysostosis, Burn-McKeown syndrome, and oculo-auriculo-vertebral syndrome.
9 Ways to Protect Your Psychological Health
What are the Symptoms of Pregnancy in 7 Days? How to Understand Early Pregnancy?