Fetal Akinesia Deformation Sequence: Genetic Testing And Prognosis

Fetal akinesia deformation sequence (FADS) describes a pattern of reduced or absent fetal movement that leads to secondary abnormalities such as joint contractures, abnormal limb positioning, facial changes, poor lung development and, in some cases, excess amniotic fluid. It is a clinical pattern rather than a single disease, which makes diagnosis and counselling particularly complex.

The underlying cause may involve the brain, spinal cord, peripheral nerves, neuromuscular junction, skeletal muscle, connective tissue or chromosomes. A genetic explanation is found in some families, while other cases remain unexplained even after extensive testing. The result of a scan should therefore be treated as the beginning of an investigation rather than a definitive prediction about a baby’s outcome.

For clinicians and families in Australia, assessment often involves a maternal-fetal medicine specialist, genetic counsellor, clinical geneticist, sonographer and neonatology team. The FAOPS 2020 congress was developed around perinatal and neonatal medicine, reflecting the multidisciplinary expertise needed when fetal movement, development and newborn care intersect.

Recognising The Pattern Before Birth

Ultrasound may identify reduced limb movement, fixed flexion or extension of joints, clenched hands, club feet, an unusually curved spine, facial profile changes or a persistently unusual fetal position. Polyhydramnios can occur when reduced swallowing affects the regulation of amniotic fluid. Fetal growth may be normal, restricted or difficult to interpret depending on the cause and gestational age.

A single scan cannot always distinguish true akinesia from a temporary period of reduced activity. Maternal perception of movement is also influenced by placental position, gestational age and the baby’s sleep-wake cycle. Repeated targeted ultrasound examinations can assess movement over time and look for associated findings, including thoracic size, diaphragmatic motion, swallowing, brain structure and the progression of contractures.

The morphology scan commonly performed around 18 to 22 weeks in Australia may raise the initial concern, but earlier findings can appear during first-trimester or early second-trimester imaging. A detailed review should include the placenta, amniotic fluid, fetal anatomy and the possibility of twin-related complications. When a local service cannot provide advanced fetal imaging, referral to a tertiary unit in Sydney, Melbourne, Brisbane, Perth or another regional centre may be appropriate.

Why The Cause Matters For Prognosis

The clinical outlook varies widely because FADS includes several biological pathways. Severe pulmonary hypoplasia is a major concern: a baby may have structurally normal airways but insufficient lung development to breathe effectively after birth. The degree of chest restriction, gestational age at delivery, muscle strength and the presence of heart, brain or kidney abnormalities all influence neonatal management.

Some causes are lethal before or shortly after birth, particularly when there is profound muscle weakness, severe lung underdevelopment or extensive multisystem disease. Other babies survive and may have treatable contractures, feeding difficulties or a defined neuromuscular condition. A normal brain scan does not exclude a serious disorder, and an apparently isolated limb posture does not guarantee a mild outcome.

Prognosis should therefore be discussed in stages. The team can describe what is visible on ultrasound, what remains uncertain, which tests may reduce that uncertainty and what delivery-room support might be required. Families may need time to consider continuing the pregnancy, palliative care, neonatal intensive care or other options within Australian law and local hospital policy. Clear, non-directive counselling is essential.

Choosing A Genetic Testing Pathway

Testing often begins with parental history and a three-generation pedigree. Clinicians ask about previous miscarriages, stillbirths, neonatal deaths, congenital contractures, unexplained infant deaths, muscle disease and consanguinity. The family’s ancestry can help identify relevant inherited conditions, although many genetic disorders occur across population groups.

If a pregnancy is affected, diagnostic testing may involve chorionic villus sampling or amniocentesis, depending on gestation and the clinical situation. Chromosomal microarray can detect clinically significant copy-number changes that may be missed by a standard chromosome analysis. If the ultrasound pattern suggests a single-gene or neuromuscular disorder, a targeted panel or exome sequencing may be considered. Genome sequencing is increasingly available through selected public and private pathways, but access, turnaround time and funding differ between states and laboratories.

A negative result does not mean that the condition is non-genetic. Testing may fail to detect a newly recognised gene, a deep intronic variant, low-level mosaicism or a complex change that the chosen method is not designed to identify. Variant interpretation can also change as medical knowledge develops. Australian families should ask whether a laboratory is NATA-accredited, what test platform is being used, how long results may take and whether reanalysis will be offered.

Testing also has practical consequences. A result may clarify recurrence risk, guide newborn investigations, identify a condition that needs urgent treatment or reveal that a parent carries a balanced chromosome rearrangement or recessive variant. However, uncertain findings can increase distress and should be explained before a sample is taken. Genetic counselling should cover possible results, limitations, privacy, incidental findings and implications for relatives.

Interpreting Results During Pregnancy

When a pathogenic variant is identified, its meaning depends on the gene, the specific variant and whether it fits the ultrasound findings. Some genes have a broad spectrum of severity. A result associated with congenital contractures may still provide limited information about respiratory function, intellectual development or long-term mobility in an individual fetus.

Parental testing can help determine whether a variant is inherited or new. In an autosomal recessive condition, both parents may be healthy carriers and face a 25 per cent chance of an affected pregnancy in each conception. In an X-linked condition, risks may differ according to the parent carrying the variant and the sex of the fetus. A de novo variant may carry a lower recurrence risk, although parental mosaicism can alter that estimate. The genetic team should provide a personalised figure rather than relying on general percentages.

When no cause is found, the ultrasound phenotype remains important. Serial imaging may show whether movement is worsening, whether contractures are developing and whether lung growth appears adequate. Fetal MRI can sometimes add information about the central nervous system or chest, but it cannot replace genetic testing or clinical assessment.

Families may also need support with decisions about place of birth. A pregnancy with suspected severe pulmonary hypoplasia is generally best managed where maternal-fetal medicine, neonatology, paediatric surgery and palliative care are available. Long travel distances are a real consideration for families in rural and remote Australia, and planning may involve temporary relocation, accommodation and coordination with local maternity services.

Planning Newborn Care And Future Pregnancies

Before birth, a joint meeting can establish whether the newborn is likely to need ventilation, respiratory support, feeding assistance, orthopaedic assessment or genetic testing after delivery. Some babies with contractures benefit from physiotherapy, splinting and early developmental care. Others may have a progressive neuromuscular disorder requiring disease-specific treatment, respiratory monitoring or specialist follow-up.

The birth plan should reflect the best available evidence rather than the label alone. A diagnosis associated with FADS does not automatically determine whether resuscitation will be appropriate. Decisions should consider lung development, gestational age, associated anomalies, the confirmed or suspected genetic disorder and the family’s values. In Australia, public hospitals may provide coordinated multidisciplinary care, while private patients should confirm which specialists and neonatal facilities are available under their insurance and local arrangements.

Pregnancy planning after an affected fetus should begin with a review of all results, imaging and newborn records. If a familial variant is known, options may include early prenatal diagnosis, preimplantation genetic testing in an assisted-reproduction setting or targeted testing in a future pregnancy. Availability and Medicare rebates vary, and private genetic testing can involve significant out-of-pocket costs. A clinical geneticist can explain realistic options in the relevant state or territory.

Maternal health advice remains part of comprehensive perinatal care, even when the primary concern is a fetal movement disorder. Families can review evidence-based vaccination and infection prevention information, including pregnancy immunisation guidance, with their GP, obstetrician or midwife. Influenza and pertussis vaccination do not cause or treat FADS, but routine antenatal care helps protect the pregnant person and newborn from preventable infection.

Fetal akinesia is best approached as a changing clinical picture rather than a fixed prediction. Early referral, careful imaging, appropriately selected genetic tests and honest discussion of uncertainty give families the strongest basis for decisions. Australian clinicians and families can seek coordinated advice through maternal-fetal medicine, genetics and neonatal services, with culturally safe care and practical support suited to their community.

If a scan has raised concern about reduced fetal movement or contractures, arrange prompt review with an obstetric or maternal-fetal medicine team and request genetic counselling before choosing tests. Bring previous scan reports, family medical information and details of any affected relatives so the team can build a complete assessment and plan the next steps.