Skeletal Dysplasias

In skeletal dysplasias, the process of 'ossification' (turning cartilage into bone) is disrupted. This usually results in:

• Micromelia: Very short limbs.
• Bowing: Curves in the long bones.
• Fractures: Breakages that happen inside the womb (common in Osteogenesis Imperfecta).
• Thoracic Hypoplasia: A very small, bell-shaped chest, which is the most critical factor in determining if the baby can breathe after birth.

Skeletal dysplasias are rare, occurring in about 1 in 4,000 to 5,000 births.

• Genetic Mutations: Most cases are caused by a new (de novo) genetic change that isn't inherited from the parents.
• Maternal/Paternal Age: Some types, like Achondroplasia, are more common in pregnancies where the father is older (advanced paternal age).
• Family History: In some cases, a dysplasia can be inherited as a dominant or recessive trait.

The diagnostic journey at the MFM Unit is meticulous, as many different dysplasias look similar on a standard scan:

1. Comprehensive Biometry: Measuring every long bone (femur, humerus, radius, ulna, tibia, fibula) and comparing them to specific charts.
2. Chest-to-Abdomen Ratio: This is the most important measurement to determine the 'lethality'—if the chest is too small to allow the lungs to grow.
3. 3D/4D Ultrasound: We use 3D imaging to look at the shape of the skull, the profile of the face, and the positioning of the hands and feet.
4. Genetic Testing: We strongly recommend Amniocentesis with an NGS (Next Generation Sequencing) panel focused on skeletal genes to identify the exact type and mutation.

During pregnancy, management focuses on a detailed diagnosis and compassionate counseling.

• Multidisciplinary Team: You will meet with MFM specialists, geneticists, and neonatologists.
• Delivery Planning: For non-lethal types, delivery is planned at a tertiary center. Most babies can be delivered vaginally unless the baby's head is very large (macrocephaly).
• Compassionate Care: For lethal types, we provide a 'Comfort Care' plan, focusing on creating a peaceful and supportive environment for the family and the baby at birth.

The outlook varies completely based on the specific type of dysplasia:

• Non-Lethal (e.g., Achondroplasia): These children have a normal life expectancy and intelligence but will be short in stature and may require orthopedic support.
• Lethal (e.g., Thanatophoric Dysplasia): These conditions are unfortunately not compatible with life after birth because the lungs are too small to function.
• Intermediate (e.g., Osteogenesis Imperfecta Type I): These children have bones that break easily but with modern medical treatment, they can lead very active lives.

If your sonographer mentions that your 'baby's legs are measuring more than 3-4 weeks behind' or that the 'limbs look curved,' an immediate referral to the MFM Unit is necessary.

Our consultants, including Dr. Leanne Bricker, are internationally recognized for their expertise in fetal structural anomalies. We provide the high-resolution imaging and the advanced genetic triage required to move from 'short bones' to a definitive, clear diagnosis.