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Otopalatodigital syndrome type 1
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Otopalatodigital syndrome type 1

Otopalatodigital syndrome type 1 is a rare genetic disorder primarily characterized by skeletal abnormalities, hearing loss, and distinct facial features.

Overview

This condition is part of a group known as otopalatodigital spectrum disorders. It is generally the mildest form, involving malformations of the tiny bones in the ears, palate development issues, and skeletal abnormalities in the digits.

Symptoms

  • Facial Features: Wide-set and downward-slanting eyes, prominent brow ridges, and a broad, flat nose.
  • Skeletal Abnormalities: Blunt, square-shaped (spatulate) fingertips, shortened thumbs and big toes, unusually long second toes, and a wide gap between the first and second toes (sandal gap).
  • Other Features: Hearing loss, potential opening in the roof of the mouth (cleft palate), hypodontia (fewer teeth than normal), mild bowing of limbs, and limited joint range of motion.

Causes

The syndrome is caused by "gain-of-function" mutations in the FLNA gene. This gene produces the protein filamin A, which helps build the cytoskeleton—the network of filaments that gives cells structure and allows them to move. These mutations increase the protein's ability to bind to actin, which is believed to impair the stability of the cytoskeleton and disrupt skeletal development.

Inheritance

This condition is inherited in an X-linked pattern. Because males have only one X chromosome, a single mutation is sufficient to cause the condition. Females have two X chromosomes; one altered copy may lead to milder features or no symptoms at all. Fathers cannot pass X-linked traits to their sons.

Frequently Asked Questions

Parents and clinicians often first notice the condition during routine newborn examinations or pediatric checkups. Key early indicators include the distinctive "sandal gap," which is an unusually wide space between the first and second toes, as well as blunt, square-shaped fingertips. Additionally, infants may exhibit a high-arched or cleft palate, which can cause feeding difficulties, and parents might observe that the child is not responding to sounds as expected, prompting an early hearing evaluation. How does the X-linked inheritance pattern affect the risk for future children and family members?::Because the condition is X-linked dominant, the risk depends on the sex of the parent carrying the mutation. If a mother is a carrier, there is a 50 percent chance that any child, regardless of sex, will inherit the mutated gene. If a father has the condition, he will pass the mutation to all of his daughters, who will be carriers or affected, but none of his sons, as he passes his Y chromosome to them. Genetic counseling is recommended for families to understand these specific probabilities and to discuss testing options for at-risk relatives. What specific interventions are required to manage the hearing loss and dental issues associated with this condition?::Management is multidisciplinary and begins in early childhood. For hearing loss, which is often conductive due to malformations of the middle ear bones, regular audiology monitoring is essential. Hearing aids may be prescribed, and in some cases, surgical correction of the ear bones is considered to improve hearing. For dental issues like hypodontia (missing teeth) or malocclusion, early consultation with a pediatric orthodontist and prosthodontist is critical to plan for tooth replacement and alignment, ensuring proper jaw development and function.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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