FGFR2 Gene

Lacrimo-auriculo-dento-digital (LADD) syndrome is a genetic disorder that mainly affects the eyes, ears, mouth, and hands. LADD syndrome is characterized by defects in the tear-producing lacrimal system (lacrimo-), ear problems (auriculo-), dental abnormalities (dento-), and deformities of the fingers (digital).

The lacrimal system consists of structures in the eye that produce and secrete tears. Lacrimal system malformations that can occur with LADD syndrome include an underdeveloped or absent opening to the tear duct at the edge of the eyelid (lacrimal puncta) and blockage of the channel (nasolacrimal duct) that connects the inside corner of the eye where tears gather (tear sac) to the nasal cavity. These malformations of the lacrimal system can lead to chronic tearing (epiphora), inflammation of the tear sac (dacryocystitis), inflammation of the front surface of the eye (keratoconjunctivitis), or an inability to produce tears.

Ears that are low-set and described as cup-shaped, often accompanied by hearing loss, are a common feature of LADD syndrome. The hearing loss may be mild to severe and can be caused by changes in the inner ear (sensorineural deafness), changes in the middle ear (conductive hearing loss), or both (mixed hearing loss).

People with LADD syndrome may have underdeveloped or absent salivary glands, which impairs saliva production. A decrease in saliva leads to dry mouth (xerostomia) and a greater susceptibility to cavities. Individuals with LADD syndrome often have small, underdeveloped teeth with thin enamel and peg-shaped front teeth (incisors).

Hand deformities are also a frequent feature of LADD syndrome. Affected individuals may have abnormally small or missing thumbs. Alternatively, the thumb might be duplicated, fused with the index finger (syndactyly), abnormally placed, or have three bones instead of the normal two and resemble a finger. Abnormalities of the fingers include syndactyly of the second and third fingers, extra or missing fingers, and curved pinky fingers (fifth finger clinodactyly). Sometimes, the forearm is also affected. It can be shorter than normal with abnormal wrist and elbow joint development that limits movement.

People with LADD syndrome may also experience other signs and symptoms. They can have kidney problems that include hardening of the kidneys (nephrosclerosis) and urine accumulation in the kidneys (hydronephrosis), which can impair kidney function. Recurrent urinary tract infections and abnormalities of the genitourinary system can also occur. Some people with LADD syndrome have an opening in the roof of the mouth (cleft palate) with or without a split in the upper lip (cleft lip). The signs and symptoms of this condition vary widely, even among affected family members.

Beare-Stevenson cutis gyrata syndrome is a genetic disorder that typically features skin abnormalities and the premature fusion of certain bones of the skull (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape of the head and face.

Many of the characteristic facial features of Beare-Stevenson cutis gyrata syndrome result from the premature fusion of the skull bones. The head is unable to grow normally, which leads to a cloverleaf-shaped skull, wide-set and bulging eyes, ear abnormalities, and an underdeveloped upper jaw. Early fusion of the skull bones also affects the growth of the brain, causing delayed development and intellectual disability.

A skin abnormality called cutis gyrata is also characteristic of this disorder. The skin has a furrowed and wrinkled appearance, particularly on the face, near the ears, and on the palms and soles of the feet. Additionally, thick, dark, velvety areas of skin (acanthosis nigricans) are sometimes found on the hands and feet and in the genital region.

Additional signs and symptoms of Beare-Stevenson cutis gyrata syndrome can include a blockage of the nasal passages (choanal atresia), a malformation of the airways (tracheal cartilaginous sleeve), overgrowth of the umbilical stump (tissue that normally falls off shortly after birth, leaving the belly button), and abnormalities of the genitalia and anus. The medical complications associated with this condition are often life-threatening in infancy or early childhood.

Saethre-Chotzen syndrome is a genetic condition characterized by the premature fusion of certain skull bones (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape of the head and face.

Most people with Saethre-Chotzen syndrome have prematurely fused skull bones along the coronal suture, the growth line that goes over the head from ear to ear. Other parts of the skull may be malformed as well. These changes can result in an abnormally shaped head, a high forehead, a low frontal hairline, droopy eyelids (ptosis), widely spaced eyes, and a broad nasal bridge. One side of the face may appear noticeably different from the other (facial asymmetry). Most people with Saethre-Chotzen syndrome also have small, rounded ears.

The signs and symptoms of Saethre-Chotzen syndrome vary widely, even among affected individuals in the same family. This condition can cause mild changes in the hands and feet, such as partial fusion of the skin between the second and third fingers on each hand and a broad or duplicated first (big) toe. Delayed development and learning difficulties have been reported, although most people with this condition are of normal intelligence. Less common signs and symptoms of Saethre-Chotzen syndrome include short stature, abnormalities of the bones of the spine (the vertebra), hearing loss, and heart defects.

Robinow-Sorauf syndrome is a condition with features similar to those of Saethre-Chotzen syndrome, including craniosynostosis and broad or duplicated great toes. It was once considered a separate disorder, but was found to result from mutations in the same gene and is now thought to be a variant of Saethre-Chotzen syndrome.

Jackson-Weiss syndrome is a genetic disorder characterized by foot abnormalities and the premature fusion of certain skull bones (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape of the head and face.

Many of the characteristic facial features of Jackson-Weiss syndrome result from premature fusion of the skull bones. Abnormal growth of these bones leads to a misshapen skull, widely spaced eyes, and a bulging forehead.

Foot abnormalities are the most consistent features of Jackson-Weiss syndrome. The first (big) toes are short and wide, and they bend away from the other toes. Additionally, the bones of some toes may be fused together (syndactyly) or abnormally shaped. The hands are almost always normal.

Some individuals with Jackson-Weiss syndrome have hearing impairment. People with Jackson-Weiss syndrome usually have normal intelligence and a normal life span.

Pfeiffer syndrome is a genetic disorder characterized by the premature fusion of certain skull bones (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape of the head and face. Pfeiffer syndrome also affects bones in the hands and feet.

Many of the characteristic facial features of Pfeiffer syndrome result from premature fusion of the skull bones. Abnormal growth of these bones leads to bulging and wide-set eyes, a high forehead, an underdeveloped upper jaw, and a beaked nose. More than half of all children with Pfeiffer syndrome have hearing loss; dental problems are also common.

In people with Pfeiffer syndrome, the thumbs and first (big) toes are wide and bend away from the other digits. Unusually short fingers and toes (brachydactyly) are also common, and there may be some webbing or fusion between the digits (syndactyly).

Pfeiffer syndrome is divided into three subtypes. Type 1, also known as classic Pfeiffer syndrome, has symptoms as described above. Most individuals with type 1 Pfeiffer syndrome have normal intelligence and a normal life span. Types 2 and 3 are more severe forms of Pfeiffer syndrome that often involve problems with the nervous system. The premature fusion of skull bones can limit brain growth, leading to delayed development and other neurological problems. In addition, individuals with type 2 or 3 can have fusion of the bones (ankylosis) in the elbow or other joints, limiting mobility, and abnormalities of the face and airways, which can cause life-threatening breathing problems. Type 2 is distinguished from type 3 by the presence of a cloverleaf-shaped head, which is caused by more extensive fusion of bones in the skull.

Apert syndrome is a genetic disorder characterized by skeletal abnormalities. A key feature of Apert syndrome is the premature closure of the bones of the skull (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape of the head and face. In addition, a varied number of fingers and toes are fused together (syndactyly).

Craniosynostosis causes many of the characteristic facial features of Apert syndrome. Premature fusion of the skull bones prevents the head from growing normally, which leads to a sunken appearance in the middle of the face (midface hypoplasia), a beaked nose, a wrinkled forehead, and an opening in the roof of the mouth (a cleft palate). In individuals with Apert syndrome, an underdeveloped upper jaw can lead to dental problems, such as missing teeth, irregular tooth enamel, and crowded teeth.

Many individuals with Apert syndrome have vision problems due to eye abnormalities, which can include bulging eyes (exophthalmos), wide-set eyes (hypertelorism), outside corners of the eyes that point downward (downslanting palpebral fissures), eyes that do not look in the same direction (strabismus), and shallow eye sockets (ocular proptosis). Some people with Apert syndrome have hearing loss or recurrent ear infections due to malformed ear structures.

Abnormal development of structures in the face and head can also cause partial blockage of the airways and lead to breathing difficulties in people with Apert syndrome. Craniosynostosis also affects development of the brain, which can disrupt intellectual development. Cognitive abilities in people with Apert syndrome range from normal to mild or moderate intellectual disability.

Individuals with Apert syndrome have syndactyly of the fingers and toes. The severity of the fusion varies, although the hands tend to be more severely affected than the feet. Most commonly, three digits on each hand and foot are fused together. In the most severe cases, all of the fingers and toes are fused. Rarely, people with Apert syndrome may have extra fingers or toes (polydactyly). Some people with Apert syndrome have abnormalities in the bones of the elbows or shoulders. These bone problems can restrict movement and impede everyday activities. In some people, abnormalities occur in both sides of the body, but in others, only one side is affected.

Additional signs and symptoms of Apert syndrome can include unusually heavy sweating (hyperhidrosis), oily skin with severe acne, or patches of missing hair in the eyebrows.