CoGenesis® Dysmorphic & congenital abnormality syndromes

CoGenesis® Dysmorphic & congenital abnormality syndromes is a next-generation sequencing (NGS) virtual panel covering 758 genes across 10 disease groups, designed to uncover the genetic basis of dysmorphic features, multiple congenital anomalies, and complex malformation syndromes.

Congenital malformation syndromes are among the most clinically diverse and genetically heterogeneous conditions in medicine. Collectively, congenital anomalies affect approximately 3% of live births and are a leading cause of childhood hospitalisation, disability, and mortality. Many affected children experience a prolonged "diagnostic odyssey"—undergoing years of specialist consultations, imaging, and piecemeal testing before a molecular diagnosis is established. NGS-based comprehensive panel testing provides a single, efficient route to diagnosis.

The panel spans a broad range of syndrome categories:

• RASopathies: Mutations in components of the RAS–MAPK signalling pathway (HRAS, KRAS, NRAS, BRAF, MAP2K1, MAP2K2, LZTR1) underlie Noonan syndrome, CFC syndrome, Costello syndrome, and related conditions—collectively affecting ~1 in 1,000 births. These share features of facial dysmorphism, short stature, cardiac defects, and variable learning difficulties.

• Chromatin remodeling syndromes: Kabuki syndrome (KMT2D, KDM6A), Cornelia de Lange syndrome (NIPBL, SMC1A, HDAC8), KAT6A/B syndromes, and Coffin-Siris syndrome (ARID1A, ARID1B) cause intellectual disability, growth restriction, and distinctive facial appearances.

• DNA repair deficiency syndromes: Fanconi anemia (FANCA–FANCM), Bloom syndrome (BLM), Nijmegen breakage syndrome (NBN), and Xeroderma pigmentosum (ERCC1–ERCC8) cause DNA damage hypersensitivity with progressive bone marrow failure, cancer predisposition, and dysmorphic features.

• Ciliopathies: Joubert syndrome (CEP290, CC2D2A, KIAA0586), Meckel-Gruber syndrome (MKS1, CEP290), and related genes cause organ laterality defects, polydactyly, and retinal dystrophy alongside dysmorphic craniofacial features.

• Peroxisome biogenesis disorders: Mutations in PEX genes (PEX1, 2, 3, 5–7, 10–16, 19, 26) cause Zellweger spectrum disorders—severe neonatal dysmorphia with liver disease, neuronal migration defects, and profound hypotonia.

• Skeletal and limb malformations: FGFR1/2/3, GDF5, NOG, HOXA13, HOXD13 cover craniosynostosis, brachydactyly, and other limb patterning defects.

• Congenital heart defects: GATA4, GATA6, NKX2-5, NOTCH1, NOTCH2 mutations underlie syndromic and non-syndromic congenital heart disease.

A molecular diagnosis directly informs management: RASopathy patients benefit from cardiac and oncological surveillance; Fanconi anemia diagnosis triggers haematopoietic stem cell transplant evaluation; Zellweger spectrum requires targeted dietary and enzyme supplementation. For families, a confirmed diagnosis provides accurate recurrence risk counselling and enables cascade testing of at-risk relatives.

1. Establishing a molecular diagnosis in infants or children presenting with dysmorphic features, multiple congenital anomalies, or malformation syndromes without a specific clinical diagnosis.
2. Investigating the genetic basis of RASopathies (Noonan, CFC, Costello), chromatin remodeling disorders (Kabuki, Cornelia de Lange, KAT6A/B), or DNA repair deficiency syndromes (Fanconi anemia, Bloom, Xeroderma pigmentosum).
3. Evaluating syndromic congenital heart defects, microcephaly, craniosynostosis, or limb and skeletal malformations with suspected genetic aetiology.
4. Identifying ciliopathy-associated syndromes (Joubert, Meckel-Gruber spectrum) or peroxisome biogenesis disorders (Zellweger spectrum) presenting with neonatal hypotonia, organ malformations, or retinal abnormalities.
5. Supporting reproductive counselling and enabling cascade testing in families affected by a congenital syndrome.

10 sub-panels included:

4mL Peripheral blood (EDTA), 2mL saliva, or buccal swab

Preferred sample type:

• 4mL Blood (EDTA tube),
• Codex-provided buccal swabs (4 swabs)
• Codex-provided saliva collection kit (2mL)

Saliva or buccal swab sample collection: Follow the enclosed instructions; do not eat, drink, or smoke for 30 minutes before collection.

• Results may identify pathogenic, likely pathogenic, or variants of uncertain significance (VUS).
• Positive findings can inform risk‑reducing strategies and treatment options.
• Genetic counseling is recommended to help families understand implications.

Dysmorphic syndromes and congenital malformations collectively affect approximately 3% of live births and represent the leading cause of infant mortality in developed countries. The genetic architecture is exceptionally heterogeneous: more than 7,000 single-gene disorders are documented in OMIM, the majority with perinatal or early childhood onset and a significant proportion presenting with dysmorphic features as the cardinal manifestation.

RASopathies are among the most prevalent single-gene syndromic groups, collectively affecting ~1 in 1,000 births. Noonan syndrome (PTPN11, SOS1, RAF1, KRAS, NRAS, BRAF, LZTR1 and others) is characterised by short stature, congenital heart defects (most commonly hypertrophic cardiomyopathy or pulmonary stenosis), facial dysmorphism, and variable neurodevelopmental impact. Molecular subtyping determines cancer surveillance: PTPN11 gain-of-function variants confer elevated risk for juvenile myelomonocytic leukaemia; CBL mutations require renal surveillance.

Chromatin remodeling disorders, including Cornelia de Lange syndrome (NIPBL, SMC1A, SMC3, RAD21, HDAC8), Kabuki syndrome (KMT2D, KDM6A), and KAT6A/B syndromes, share overlapping features of intellectual disability, growth restriction, and characteristic facial appearances. Clinical overlap between these conditions frequently necessitates molecular testing for definitive diagnosis and recurrence risk counselling.

Fanconi anemia (FA), caused by biallelic mutations in any of 22 FANC genes (including FANCA, FANCC, FANCD2, FANCG, FANCL, FANCM), affects ~1 in 130,000 births. It presents with variable congenital anomalies, progressive aplastic anaemia, and high cancer risk (particularly acute myeloid leukaemia and squamous cell carcinoma). Molecular confirmation of complementation group determines eligibility for allogeneic haematopoietic stem cell transplantation, the only curative treatment for the haematological manifestations.

Peroxisome biogenesis disorders (Zellweger spectrum, caused by PEX gene mutations) present with severe neonatal dysmorphism, profound neurological impairment, liver disease, and retinal dystrophy. Early molecular diagnosis enables initiation of ursodeoxycholic acid, fat-soluble vitamin supplementation, and specialist palliative planning. Ciliopathy-associated syndromes (Joubert syndrome, Meckel-Gruber syndrome) often involve polydactyly, retinal dystrophy, and renal anomalies; molecular confirmation guides ophthalmological and renal surveillance.

The diagnostic yield of comprehensive gene panel testing for dysmorphic syndromes ranges from 20–40% in unselected paediatric cohorts and rises to >50% in cohorts with features strongly suggestive of known syndromic categories. A molecular diagnosis eliminates the diagnostic odyssey, enables condition-specific management pathways, and provides families with accurate recurrence risk information for future pregnancies.