Trisomy 3p

At a glance

Duplication of the short arm of chromosome 3 with severe delay in mental development, craniofacial dysmorphism, urogenital maldevelopment, and various occasional anomalies, including cardiac defects, cleft lip and palate, holoprosencephaly, dermatoglyphic findings, and other malformations.

Synonyms

Chromosome 3p Duplication Syndrome; 3p⁺ Syndrome; Partial Trisomy 3p.

Incidence

Very rare. More than 50% of children die within the first 2 years of life.

Genetic inheritance

Duplications include dup(3)(pter-p25), dup(3)(pter-p11), dup(3)(pter-p23), and dup(3)(p25-pter). Most reported cases have resulted from paternal or maternal balanced translocation.

Clinical aspects

Head and neck: brachycephaly, holoprosencephaly, square face with frontal bossing, flat occiput, temporal indentations, facial clefts, and full cheeks. Ears: malformed auricles. Eyes: hypertelorism, iris coloboma, microphthalmia, cyclopia, down-slanting palpebral fissures. Mouth and nose: large mouth, cleft lip and palate, short nose with broad and flat bridge, choanal atresia. Cardiac defects: congenital heart defects including tetralogy of Fallot, ventricular septal defect, hypoplastic heart, and transposition of the great vessels. Central nervous system: seizures. Muscles: severe hypotonia. Gastrointestinal: esophageal atresia, atresia of the colon and rectum. Other features: short stubby hands and feet, camptodactyly, excessive fingertip whorls are the dermatoglyphic findings, spinal hemivertebrae, hypogonadism, hypospadias, micropenis, cryptorchidism, and kidney hypoplasia.

Precautions before anesthesia

Evaluate cardiac function (clinical, echocardiography, ECG) and renal function (echography, urea, creatinine, electrolytes). Seizure medication should be optimized prior to anesthesia and surgery. Anesthesia consultation should be considered to assess airway condition.

Anesthetic considerations

Careful intraoperative positioning should be done (vertebral anomalies, joint contractures). Direct laryngoscopy and tracheal intubation has, however, not proven to be difficult in the few cases reported. The presence of a large mouth and microstomia seem to facilitate direct laryngoscopy. However, special attention to the possibility of a challenging direct laryngoscopy and tracheal intubation should always be a consideration. Implications of associated cardiovascular congenital anomalies should be treated according to the clinical presentation. Perimedullar anesthesia is often contraindicated or difficult because of vertebral and spine anomalies.

Pharmacological implications

Consider anesthetic drug interactions with antiepileptic medications. Prophylactic antibiotics should be given as indicated in cases of cardiac defects. Maintaining spontaneous ventilation during laryngoscopy might be judicious until direct laryngeal vision is confirmed and tracheal intubation can be performed without problems. Avoid anesthetic drugs with marked cardiovascular effects.

References