Antley-Bixler Syndrome

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Antley-Bixler syndrome is a rare genetic disorder that can cause structural changes to the skull, bones of the face, and other skeletal abnormalities. It is a rare, distinct craniosynostosis syndrome, accompanied by ambiguous genitalia and impaired steroidogenesis. It is reported that this disorder is caused...

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বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

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Article Summary

Antley-Bixler syndrome is a rare genetic disorder that can cause structural changes to the skull, bones of the face, and other skeletal abnormalities. It is a rare, distinct craniosynostosis syndrome, accompanied by ambiguous genitalia and impaired steroidogenesis. It is reported that this disorder is caused by mutations in the P450 oxidoreductase (POR; OMIM #124015) gene via autosomal recessive inheritance. The disorder is typically associated with...

Key Takeaways

  • This article explains Symptoms in simple medical language.
  • This article explains Causes in simple medical language.
  • This article explains Diagnosis in simple medical language.
  • This article explains Treatment in simple medical language.
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  • Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
  • New weakness, severe pain, high fever, or symptoms after a serious injury.
  • Any symptom that feels urgent, unusual, or unsafe for the patient.
1

Emergency now

Use emergency care for severe, sudden, rapidly worsening, or life-threatening symptoms.

2

See a doctor

Book a professional medical evaluation if symptoms persist, worsen, recur often, affect daily activities, or occur in a high-risk patient.

3

Learn safely

Use this article to understand possible causes, tests, treatment options, prevention, and questions to ask your clinician.

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Definition

Antley-Bixler syndrome is a rare genetic disorder that can cause structural changes to the skull, bones of the face, and other skeletal abnormalities. It is a rare, distinct craniosynostosis syndrome, accompanied by ambiguous genitalia and impaired steroidogenesis. It is reported that this disorder is caused by mutations in the P450 oxidoreductase (POR; OMIM #124015) gene via autosomal recessive inheritance. The disorder is typically associated with premature closure of joints (cranial sutures) between particular bones of the skull (craniosynostosis). Many affected infants and children also may have a prominent forehead, underdeveloped midfacial regions (midfacial hypoplasia), protruding eyes (proptosis), and low-set ears.

Additional skeletal abnormalities are usually present, such as fusion of certain bones of the arms (e.g., radiohumeral or radioulnar synostosis), long, thin fingers and toes (arachnodactyly), and bowing of the thigh bones. In addition, certain joints in the arms and legs may become permanently flexed or extended in fixed postures (joint contractures), resulting in restricted movements.

Antley-Bixler syndrome can be caused by changes (mutations) in the POR gene and the FGFR2 gene.

Symptoms

Antley-Bixler syndrome is typically characterized by structural changes in the skull, bones of the face, and other skeletal abnormalities. In most affected infants, there is premature closure of the joints (sutures) between different portions of the skull (craniosynostosis) Additional craniofacial abnormalities may include a large, prominent forehead (frontal bossing), underdeveloped middle regions of the face (midfacial hypoplasia); a large nose with a low nasal bridge; protruding eyes (proptosis); and low-set, malformed (dysplastic) ears.

Antley-Bixler syndrome is also characterized by other distinctive skeletal changes. These may include the fusion of bones of the arms that are next to each other (adjacent), particularly the forearm bone on the thumb side of the arm (radius) and the long bone of the upper arm (radiohumeral synostosis). In addition, there can be permanent flexion or extension of certain joints in a fixed position (joint contractures), leading to limited movements of the fingers, wrists, ankles, knees, and/or hips. Affected individuals may also have unusually long, thin fingers and toes (camptodactyly), structural changes on the bottom of the feet (“rocker-bottom” feet); or bowing and/or fractures of the thigh bones.

In some affected infants, a bony or thin layer of tissue may block the passageway between the nose and throat (choanal stenosis or atresia), leading to difficulty breathing. If this symptom is not treated promptly early in life, it may cause life-threatening respiratory problems.

Some individuals with Antley-Bixler syndrome may have additional symptoms. These may include certain structural defects of the urinary and genital organs (urogenital defects), inability to produce cholesterol from steroids (impaired steroidogenesis), developmental delay, and intellectual disability. ABS1 is the name given to the subtype that includes genital anomalies and disordered steroidogenesis. ABS1 is also a severe form of cytochrome P450 oxidoreductase deficiency. ABS2 is the name given to the subtype that does not include genital anomalies and disordered steroidogenesis.

Causes

Antley-Bixler syndrome can be caused by mutations in two different genes. ABS1 is associated with mutations in the POR gene and is inherited in an autosomal recessive pattern. This means that a person will have ABS1 when he or she inherits two non-working copies of the POR gene, one from each parent. If an individual receives one working copy of the gene and one not working copy of the gene, the person will be a carrier of the syndrome but will not show symptoms. When both parents are carriers of the syndrome, there is a 25 percent chance the child will have ABS1. Additionally, there is a fifty percent chance their child will be carriers of the condition (just like their parents) and a twenty-five percent chance that their child will receive both working copies of the gene. The risk is the same for each pregnancy.

ABS2 is associated with mutations in the FGFR2 gene. In this subtype, the condition is thought to be caused by spontaneous (new) changes in the gene. The condition then may be transmitted in an autosomal dominant pattern in subsequent generations. Dominant genetic disorders occur when only a single copy of a non-working gene is necessary to cause a particular disease. The non-working gene can be inherited from either parent or can be the result of a mutated gene in the affected individual. The risk of passing the non-working gene from an affected parent to an offspring is 50% for each pregnancy. The risk is the same for males and females.

It is important to note that several syndromes have been identified which are associated with mutations of the FGFR2 gene including Apert, Crouzon, and Pfeiffer syndromes. (For further information on these disorders, please see the “Related Disorders” section of this report below.)

There have been a few reported cases that show that symptoms similar to Antley-Bixler syndrome may have resulted from maternal use of the antifungal medication (fluconazole) during early pregnancy. There is not a lot of research showing why this medication causes symptoms similar to Antley-Bixler syndrome.

Initially, medical exome sequencing was applied using the parents’ peripheral blood genome DNA. Next, bidirectional Sanger sequencing and quantitative real-time PCR (qRT-PCR) were conducted to confirm the sequencing results. The infant was diagnosed as ABS at birth, with typical midface hypoplasia, craniosynostosis, femoral bowing, radio-ulnar synostosis, and genital anomalies. Clinical features of ABS patients include midface hypoplasia, craniosynostosis, radio-ulnar synostosis, choanal atresia or stenosis, femoral bowing and fractures, joint contractures, and arachnodactyly ()

Diagnosis

The diagnosis of Antley-Bixler syndrome is usually made after birth (postnatally) based upon a thorough clinical evaluation and characteristic physical findings. Other imaging procedures and genetic testing may also be conducted to diagnose the disorder.

In some children, a diagnosis of Antley-Bixler syndrome may be suggested before birth (prenatally) based uonttestssuch as ultrasound. Ultrasound allows us to generate an image of the developing fetus, which may then reveal characteristic findings that are associated with the disorder. If there is a known family history of the condition, targeted genetic testing is available for patient families.

Treatment

The treatment of Antley-Bixler syndrome is directed toward the specific symptoms that are seen in each individual. Such treatment requires the coordinated efforts of a team of medical professionals who may need to systematically and comprehensively plan the treatment for a child with this condition. These professionals may include pediatricians, surgeons, and physicians who specialize in disorders of specific body areas and organs. In individuals with Antley-Bixler syndrome, treatment typically includes surgery. The surgical procedures performed will depend upon the severity of the skeletal problems and their associated symptoms. multiple surgeries may be needed to treat the malformations present.

There is no cure for the condition. All treatment is supportive and aimed at managing symptoms. However, early intervention may be important in ensuring that affected children reach their potential. For example, physical therapy is typically recommended to help improve the range of movement at certain joint contractures. Other therapies that may aid in managing symptoms include occupational therapy and speech therapy.

Because this is a genetic condition, individuals with Antley-Bixler syndrome and their families would benefit from meeting with a genetic counselor. Genetic counselors are professionals who have specialized education in genetics and counseling to provide personalized help patients may need as they make decisions about their genetic health.

 

References

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Prepare before seeing a doctor

A simple rural-patient checklist to help you explain symptoms clearly, ask better questions, and avoid unsafe self-treatment.

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

  • Write when the problem started and how it changed.
  • Bring old prescriptions, investigation reports, and current medicines.
  • Write allergies, pregnancy status, diabetes, kidney/liver disease, and major past illnesses.
  • Bring one family member if the patient is weak, elderly, confused, or a child.

Questions to ask

  • What is the most likely cause of my symptoms?
  • Which danger signs mean I should go to hospital quickly?
  • Which tests are necessary now, and which can wait?
  • How should I take medicines safely and what side effects should I watch for?
  • When should I come for follow-up?

Tests to discuss

  • Vital signs: temperature, pulse, blood pressure, oxygen saturation
  • Basic physical examination by a clinician
  • CBC, urine test, blood sugar, or imaging only when clinically needed

Avoid these mistakes

  • Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
  • Do not hide pregnancy, kidney disease, ulcer, allergy, or blood thinner use.
  • Do not delay emergency care when danger signs are present.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

  • Drink warm safe fluids and avoid smoke/dust exposure.
  • Use a mask and seek testing advice if infection is suspected.
  • Breathing difficulty should be treated as a warning sign.

OTC medicine safety

  • Cough syrups are not always needed; ask a clinician or pharmacist, especially for children.
  • Do not use leftover antibiotics for cough without medical advice.

Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
  • Do not use steroid tablets or injections casually for quick relief.
  • Do not delay emergency care because of home remedies.

Get urgent help if

  • Shortness of breath, blue lips, chest pain, coughing blood, severe weakness, or low oxygen needs urgent care.
Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Doctor / qualified healthcare provider
Tests to discuss with doctor
  • Basic vital signs: temperature, pulse, blood pressure, oxygen level if needed
  • Relevant blood, urine, imaging, or specialist tests only after clinical assessment
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: Antley-Bixler Syndrome

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

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Emergency first: Severe chest pain, breathing trouble, unconsciousness, stroke signs, severe injury, heavy bleeding, or rapidly worsening symptoms need urgent local medical care now.

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

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