Skeletal malformations in fetuses with Meckel syndrome

Area of Science:

• Medical Genetics
• Skeletal Dysplasias
• Developmental Biology

Background:

• Meckel syndrome is a rare autosomal recessive developmental disorder.
• Characterized by a spectrum of congenital anomalies, including central nervous system malformations, cystic renal disease, and hepatic fibrosis.
• Skeletal anomalies are frequently observed but less systematically studied.

Purpose of the Study:

• To investigate the types and patterns of skeletal malformations in fetuses with Meckel syndrome.
• To evaluate the utility of skeletal analysis in the phenotypic characterization of Meckel syndrome.

Main Methods:

• Post-mortem skeletal examination of six fetuses diagnosed with Meckel syndrome (gestational age 16-23 weeks).
• Utilized whole-body radiography and specialized radiographic techniques.
• Detailed analysis of limb bones (metacarpals, metatarsals), cranial base, and lumbar spine.

Main Results:

• Identified polydactyly in both upper and lower limbs, with four distinct types based on metacarpal and metatarsal morphology.
• Observed greater symmetry in limb malformations within the same limb type (hands or feet) compared to between hands and feet.
• Malformations of the cranial base (occipital bone, postsphenoid bone) occurred in five fetuses.
• Lumbar vertebral body clefts were present in three fetuses.
• Only one foot exhibited normal development.

Conclusions:

• Skeletal radiography reveals consistent patterns of polydactyly and other malformations in Meckel syndrome.
• Skeletal analysis provides valuable data for comprehensive phenotypic evaluation in Meckel syndrome.
• Recommend incorporating detailed skeletal assessment into future Meckel syndrome evaluations.