postaxial acrofacial dysostosis

Postaxial Acrofacial Dysostosis (POADS) Description

Postaxial acrofacial dysostosis, also known as Miller syndrome, is a rare genetic disorder that affects the development of the face and limbs. The condition is characterized by several distinct features:

• Facial abnormalities: Underdeveloped cheekbones (malar hypoplasia), an abnormally small lower jaw (micrognathia), cleft lip and/or palate, and coloboma of the eyelids.
• Limb deficiencies: Absence or underdevelopment of the fifth digital ray in hands and feet, ulnar hypoplasia, and symmetrical postaxial limb deficiencies.
• Ear abnormalities: Small and cup-shaped ears.
• Eye abnormalities: Coloboma of the eyelids and drooping of the lower eyelids.

The severity of POADS can vary among affected individuals. It is a rare condition, and little is known about its pathogenesis [1][2]. The incidence of the condition is not well-documented, but it is considered to be extremely rare [12].

References:

[1] - Characteristic features include underdeveloped cheek bones, a very small lower jaw, cleft lip and/or palate, abnormalities of the eyes, absent fifth (pinky) fingers and toes, and abnormally formed bones in the forearms and lower legs. [Context 1]

[2] - Miller syndrome, also known as postaxial acrofacial dysostosis, is a rare genetic disorder characterized by craniofacial malformations occurring along with abnormalities of the arms, hands and/or feet. Craniofacial abnormalities include underdevelopment of the cheekbones (malar hypoplasia); an abnormally small lower jaw (micrognathia ... [Context 2]

[3] - The facial characteristics include downward slanting palpebral fissures (eyelids), the absence of a portion of the lower eyelid and or eyelashes, cleft palate, recessed lower jaw, small cup shaped ears, and a ... [Context 13]

[4] - It is characterized by postaxial acrofacial dysostosis, which is defined by its postaxial limb deficiency. Craniofacial malformations, malar hypoplasia, severe micrognathia, cleft palate, small, protruding, “cup-shaped” ears, colobomas, drooping of the lower eyelids, and ... [Context 14]

Postaxial acrofacial dysostosis, also known as Miller syndrome, is a rare genetic disorder characterized by craniofacial malformations occurring along with abnormalities of the arms, hands and/or feet. The specific symptoms associated with this condition may vary from one person to another.

Common Symptoms:

• Absent or underdeveloped fifth (pinky) fingers and toes [5]
• Webbed or fused fingers or toes (syndactyly) [5]
• Small, cup-shaped ears [6], [11]
• Hearing loss caused by defects in the middle ear (conductive hearing loss) [6]
• Downslanting of the palpebral fissures (eyelids) [7], [11]
• Underdevelopment of the malar bones causing prominence of the eyes [7], [13]
• Incomplete hypoplasia, syndactyly, clinodactyly (eg, the fifth digits and, in some cases, the fourth and third digits), and other limb abnormalities [8]
• Severe micrognathia (very small lower jaw) [9], [10]
• Cleft lip and/or palate [10], [11]

Other Possible Symptoms:

• Colobomas (abnormalities of the eyelids)
• Drooping of the lower eyelids
• Abnormally formed bones in the forearms and lower legs

It's essential to note that the symptoms can vary from one person to another, even among members of the same family. A diagnosis is typically made based on a combination of clinical evaluation, medical history, and genetic testing.

References: [1], [2], [3], [4]

Diagnostic Tests for Postaxial Acrofacial Dysostosis (Miller Syndrome)

Postaxial acrofacial dysostosis, also known as Miller syndrome, is a rare genetic disorder that affects the development of the face and limbs. Diagnostic tests are essential to confirm the diagnosis and rule out other conditions.

• Genetic testing: Genetic testing can confirm the diagnosis by identifying mutations in the genes associated with postaxial acrofacial dysostosis. This test involves taking a small sample of blood from the heel or a cheek swab.
  • Analysis of DHO and orotic acid (OA) in urine, plasma, and blood-spot tests can be performed using liquid chromatography-tandem mass spectrometry [2].
• Physical examination: A thorough physical examination by a specialist is crucial to identify characteristic features such as underdeveloped cheekbones, small lower jaw, cleft lip and/or palate, abnormalities of the eyes, absent fifth (pinky) fingers and toes, and abnormally formed bones in the forearms and lower legs [5].
• Imaging studies: Imaging studies like X-rays or CT scans may be ordered to confirm the presence of skeletal abnormalities.
• Other tests: Depending on the severity of symptoms, other tests such as midgut malrotation, gastric volvulus, and renal anomalies may be performed to rule out associated conditions [8].

It's essential to consult with a specialist, such as a geneticist or a pediatrician, for an accurate diagnosis and guidance on further testing.

References:

[1] Genetic testing may confirm the diagnosis. Your healthcare provider will take a small sample of your child’s blood from their heel. In a lab, a technician will analyze the sample to identify any genetic mutations associated with postaxial acrofacial dysostosis. [2] Analysis of DHO and orotic acid (OA) in urine, plasma, and blood-spot tests can be performed using liquid chromatography-tandem mass spectrometry. [5] Physical examination by a specialist is crucial to identify characteristic features such as underdeveloped cheekbones, small lower jaw, cleft lip and/or palate, abnormalities of the eyes, absent fifth (pinky) fingers and toes, and abnormally formed bones in the forearms and lower legs. [8] Midgut malrotation, gastric volvulus, and renal anomalies may be performed to rule out associated conditions.

Treatment Options for Postaxial Acrofacial Dysostosis (POADS)

Postax

Differential Diagnosis of Postaxial Acrofacial Dysostosis

Postaxial acrofacial dysostosis, also known as Miller syndrome, is a rare genetic disorder characterized by craniofacial malformations and abnormalities of the arms, hands, and/or feet. When diagnosing this condition, it's essential to consider other syndromes that may present similar symptoms.

Similar Syndromes:

• Nager Syndrome: Also known as preaxial acrofacial dysostosis, Nager syndrome is a rare inherited disorder that affects the development of the face and limbs. It shares some similarities with postaxial acrofacial dysostosis, including craniofacial malformations and limb abnormalities.
• Treacher Collins Syndrome: This genetic disorder affects the development of the facial bones and can cause symptoms such as underdeveloped cheekbones, a small jaw, cleft palate, and cup-shaped ears. While it's not directly related to postaxial acrofacial dysostosis, it's essential to consider it in differential diagnosis.
• Mandibulofacial Dysostosis: This rare genetic disorder affects the development of the face and jaws, leading to symptoms such as underdeveloped cheekbones, a small jaw, and cleft palate. It can be confused with postaxial acrofacial dysostosis due to similar craniofacial malformations.

Key Differences:

• Location of Limb Abnormalities: Postaxial acrofacial dysostosis is characterized by abnormalities in the posterior (posterior) limbs, whereas Nager syndrome affects the anterior (anterior) limbs.
• Craniofacial Malformations: While both conditions share similar craniofacial malformations, postaxial acrofacial dysostosis tends to have more severe facial abnormalities.

References:

• [2] Miller syndrome is an extremely rare genetic condition that manifests as craniofacial, limb, and other systemic abnormalities.
• [11] Halal F, Herrmann J, Pallister PD, Opitz JM, Desgranges MF, Grenier G. Differential diagnosis of Nager acrofacial dysostosis syndrome: report of four patients with Nager syndrome and discussion of other related syndromes. Am J Med Genet. 1983;14(2):209–224.
• [15] The main differential diagnoses of Mandibulofacial Dysostoses (MFDM) are other mandibulofacial dysostoses, including Postaxial acrofacial dysostosis Miller type and Treacher Collins syndromes.