Makindo Medical Notes

A dysmorphic child presents with one or more physical abnormalities that may suggest an underlying congenital syndrome or genetic disorder. Identifying these dysmorphic features is critical for proper diagnosis, management, and prognosis. Dysmorphology refers to the study of congenital structural differences, with a focus on syndromes and developmental anomalies.

Common Dysmorphic Features

Dysmorphic features are physical traits that deviate from the norm. These traits can involve any part of the body, but commonly affect the face, head, and limbs. Common features include:

• Facial Features:
  • Micrognathia (small jaw)
  • Hypertelorism (wide-set eyes)
  • Low-set ears
  • Flattened nasal bridge
  • Cleft lip/palate
  • Up-slanting or down-slanting palpebral fissures
• Cranial Features:
  • Microcephaly (small head)
  • Macrocephaly (large head)
  • Brachycephaly (short, broad head)
  • Plagiocephaly (asymmetrical head shape)
• Limb Anomalies:
  • Polydactyly (extra fingers or toes)
  • Syndactyly (webbing of fingers or toes)
  • Clubfoot (talipes equinovarus)
  • Shortened limbs (rhizomelia or mesomelia)
• Other Features:
  • Heart defects (e.g., atrial or ventricular septal defects)
  • Spinal anomalies
  • Genitourinary abnormalities

Causes of Dysmorphic Features

• Genetic Syndromes: Chromosomal abnormalities, single-gene mutations, or polygenic/multifactorial causes may lead to dysmorphism.
  • Down Syndrome: Trisomy 21 with features like epicanthic folds, single palmar crease, and flat facial profile.
  • Turner Syndrome: 45,XO with short stature, webbed neck, and shield chest.
  • Marfan Syndrome: Autosomal dominant condition with long limbs, pectus excavatum, and lens dislocation.
  • Apert Syndrome: Craniosynostosis, fused fingers/toes, and abnormal facial development.
• Teratogens: Environmental factors like alcohol (fetal alcohol syndrome), drugs (e.g., thalidomide), or infections (e.g., rubella) during pregnancy can cause dysmorphic features.
• Sporadic Mutations: Random genetic changes may result in isolated dysmorphic features or syndromes.

Approach to Diagnosis

Diagnosing a dysmorphic child requires a systematic approach, including a detailed history, physical examination, and relevant investigations.

History Taking

• Family History: Look for a history of similar features, known syndromes, or consanguinity in parents.
• Pregnancy History: Ask about maternal exposures to drugs, infections, alcohol, or environmental hazards during pregnancy.
• Developmental History: Inquire about milestones and note any delays in physical, social, or cognitive development.
• Birth History: Preterm birth, low birth weight, or birth complications may provide important clues.

Examination

• Thorough examination of head, face, limbs, and internal systems (heart, genitourinary, etc.) for specific dysmorphic features.
• Measure growth parameters: head circumference, height, and weight to detect microcephaly, macrocephaly, short stature, or overgrowth syndromes.

Investigations

• Genetic Testing: Karyotyping or chromosomal microarray can detect chromosomal abnormalities. More specific tests like FISH (Fluorescence in Situ Hybridization) or exome sequencing may be needed for single-gene mutations.
• Imaging Studies: CT or MRI may be necessary to evaluate craniofacial structures, brain abnormalities, or skeletal deformities.
• Echocardiography: look for congenital heart defects, particularly in Down syndrome or Turner syndrome.
• Metabolic Screening: basic screening (e.g., serum amino acids, organic acids) should be done.

Management

The management of a dysmorphic child is multidisciplinary, addressing both the underlying condition and associated complications.

• Genetic Counseling: Essential for families with known genetic conditions. Counsel on inheritance patterns, recurrence risks, and prenatal diagnosis in future pregnancies.
• Developmental Support: Early intervention services, physical therapy, speech therapy, and occupational therapy may be required for children with developmental delays.
• Medical Management: Treat associated conditions like cardiac defects, hearing problems, or feeding difficulties based on the underlying syndrome.
• Surgical Intervention: In cases of craniofacial anomalies, limb deformities, or congenital heart defects, surgical correction may be necessary.
• Long-Term Follow-up: Regular monitoring for growth, development, and emerging health issues, especially in syndromes with progressive features (e.g., Marfan syndrome).

Prognosis

The prognosis of a dysmorphic child depends on the underlying cause and associated complications. Some children with mild dysmorphic features may have normal development and life expectancy, while others with more severe syndromes may experience significant health challenges and reduced quality of life. Early diagnosis and intervention can greatly improve outcomes.

References

• Genetic Syndromes and Dysmorphology Overview - NCBI
• Dysmorphology: Approach to the Infant or Child with a Congenital Anomaly - UpToDate