Hypertelorism

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Hypertelorism is one of the facial features seen in Loeys-Dietz syndrome

Hypertelorism refers to an increased distance between the orbits (eyes), with lateral displacement of the orbital walls. It is confirmed by enlarged inner canthal distance, outer canthal distance, and interpupillary distance beyond the 95th percentile for age. Isolated increase in inner canthal distance alone is termed telecanthus. True orbital hypertelorism often signals a developmental anomaly of the craniofacial skeleton.

Associated Syndromes/Conditions

Loeys-Dietz Syndrome (LDS)

An autosomal dominant connective tissue disorder characterized by arterial aneurysms and distinctive craniofacial features.​

Facial: Marked hypertelorism often with strabismus, and a bifid uvula or cleft palate.​

MSK: LDS causes joint laxity, scoliosis, pectus deformities, clubfoot, and cervical spine malformations​. These skeletal manifestations can lead to chronic joint pain, back pain, and neurologic complications (e.g. cervical instability).

Diagnostic criteria: Hypertelorism is a common clinical finding in LDS but diagnosis is confirmed by gene testing (e.g. TGFBR1/2 variants) alongside vascular features​

Aarskog-Scott Syndrome

A rare X-linked syndrome (mutation in FGD1) also known as facio-digital-genital syndrome.

Facial: Hypertelorism with round face, anteverted nostrils, a broad nasal bridge/philtrum, and often maxillary hypoplasia​

MSK: Features include short stature, ligamentous laxity, cervical vertebral anomalies (odontoid hypoplasia, occulta spina bifida) and occasionally scoliosis​. These can contribute to neck pain or neurologic symptoms from atlantoaxial instability.

Relevance: The combination of hypertelorism and musculoskeletal anomalies (joint hypermobility, spinal deformities) is a red flag for a connective tissue or developmental disorder like Aarskog, guiding monitoring for orthopedic complications (e.g. cervical spine instability, patellar dislocations).

Neurofibromatosis Type 1 (NF1)

A neurocutaneous disorder (mutation in NF1) primarily known for nerve tumors.​

Facial: NF1 can produce a characteristic coarse facial appearance with ocular hypertelorism, a broad nasal tip, flat forehead, and low-set ears​. These dysmorphic traits are especially noted in patients with large gene deletions​

MSK/Neurologic: NF1 causes multiple peripheral nerve tumors (neurofibromas) which may compress nerves (leading to neuropathic pain) and bony dysplasias (e.g. sphenoid wing dysplasia, long bone pseudarthrosis, scoliosis). Dystrophic scoliosis in NF1 can be painful and progressive, requiring intervention. Additionally, a subset of NF1 patients have overlapping Noonan syndrome features (hypertelorism, webbed neck) due to certain NF1 mutations​, along with pulmonic stenosis or other issues.

Note: The presence of hypertelorism in NF1 (sometimes called the “NF1 facies”)​ is an example of how a facial clue correlates with an underlying tendency for widespread tissue overgrowth and deformity that can cause pain (e.g. plexiform neurofibroma pain, orthopedic pain from dysplasia).

Hurler Syndrome (Mucopolysaccharidosis Type I)

An autosomal recessive lysosomal storage disorder. ​

Facial: Coarse gargoyle-like facies develop in infancy with frontal bossing, wide nasal bridge, and widely spaced eyes (true hypertelorism with proptosis).​

MSK/Neurologic: Hurler syndrome causes progressive dysostosis multiplex – joint stiffness and contractures, short neck, and cervical vertebral deformities​. Patients often suffer from restricted joint mobility and compressive neuropathies (e.g. carpal tunnel syndrome and cervical spinal cord compression) that cause pain. Although the coarse facial features (including hypertelorism) are mostly of diagnostic importance, they correlate with the severity of the skeletal disease. ​

Diagnostic criteria: Hypertelorism is not diagnostic by itself but, in a child with developmental delay, hepatosplenomegaly, and coarse facies, it prompts testing for MPS disorders.

Noonan Syndrome

A relatively common autosomal dominant RAS-pathway syndrome.

Facial: Hypertelorism with down-slanting palpebral fissures and ptosis is a hallmark, along with a low nasal bridge and high-arched palate. The neck may be webbed or broad.

MSK: Noonan syndrome patients can have pectus excavatum/carinatum, scoliosis, and hyperextensible joints. These features may lead to musculoskeletal pain (e.g. chest wall pain or back pain) in some individuals, though Noonan is more known for cardiac issues.

Relevance: The combination of hypertelorism and chest wall deformity in a short-statured child should raise suspicion for a RASopathy like Noonan​. While chronic pain is not a classic feature, hypotonia and joint laxity in infancy may predispose to delayed motor milestones and orthopedic problems requiring therapy.

Why it matters

Recognizing hypertelorism is clinically useful because it often points to an underlying syndrome that may have significant MSK or neurologic implications. For example, identifying hypertelorism in a patient with arterial tortuosity could suggest Loeys-Dietz syndrome, prompting crucial imaging for aneurysms. In a child with short stature and hypertelorism, one might evaluate for Aarskog or Noonan syndrome and thus anticipate orthopedic issues like cervical spine instability or scoliosis.

In NF1, the “hyperteloric facies”​ accompanies a predisposition to painful neurofibromas and bony lesions. By itself, hypertelorism does not cause pain, but it is a visible marker of syndromes that do—making early diagnosis and intervention possible.

Diagnostic Note

Hypertelorism is quantified by anthropometry: an inner canthal distance (ICD), outer canthal distance (OCD), and interpupillary distance (IPD) above the 95th percentile for age confirms true orbital hypertelorism​. This can be measured in clinic or via imaging. If true hypertelorism is present, a thorough dysmorphology exam and genetic evaluation are warranted.​

Many syndromes associated with hypertelorism (like NF1 or Noonan) have specific genetic tests or clinical criteria for diagnosis, where hypertelorism is one feature among many.