Trisomy 13

This chromosomal disorder is characterized by specific midline dysmorphic features and organ malformations. Usually leading to death before 6 months of life.

(Figure)

Patau Syndrome; Bartholin-Patau Syndrome; Trisomy D (Trisomy 13s).

First described by Thomas Bartholin in 1657, but recognized as a clinical syndrome when the trisomy etiology was discovered by Klaus Patau in 1960.

1:4000 to 1:10,000 live births. Age of onset: newborn. Risk factors include advanced age of mother. Sex distribution is equal.

In 75% of cases, it is manifested by a trisomy of chromosome 13, caused by meiotic nondisjunctions. Translocations (20% of cases) are also present and either associated with de novo or familial translocation with a recurrence rate of 5 to 15%. The presence of mosaicism (5%) is a result of postzygotic (postfertilization) mitotic nondisjunction; however, it is less severe than full trisomy 13, but quite variable.

A single defect during the first 3 weeks of development of the prechordal mesoderm can lead to morphologic defects of the midface, eyes, and forebrain, as well as induction defects on the prosencephalon (cerebral hemispheres, diencephalon, hypothalamus, thalamus), leading to holoprosencephaly.

Diagnosis can be evocated by the characteristic features, including microcephaly, microphthalmia, hypertelorism, cleft lip or palate, polydactyly, cardiovascular, and genitourinary and neurological abnormalities. It is confirmed by karyotype. Death often occurs before 6 months of age.

This severe disease is most often associated with midline defects: mental retardation with head malformations (microcephaly; cranial asymmetry; arhinencephaly; holoprosencephaly; cerebellar malformations; corpus callosum agenesis; neural tube defects; anencephaly; seizures; sloping forehead; wide sagittal suture and fontanels; cebocephaly; premaxillary agenesis; scalp defects; dysplastic low-set ears; microphthalmia; hypertelorism or hypotelorism; coloboma; retinal dysplasia orbital; cyclopia; choanal agenesis; cleft lip or palate) and skeleton anomalies (polydactyly of the fingers and toes, ectrodactyly, valgus deformity, spina bifida, hyperconvex narrow fingernails) are also observed. Abdomen and pelvis (Meckel diverticulum; intestinal malrotation; mobile cecum; hypoplastic penis and scrotum; cryptorchidism; bicornis uterus; microcystic and hyperlobulated kidneys; megaureter; hydronephrosis; umbilical hernia; and single umbilical artery) and thoracic organs (atrial septal defect, ventricular septal defect, coarctation of the aorta, bicuspid aortic valve, bilobed lung) are also involved. Apnea, feeding difficulty, and deafness are common.

Evaluate cardiac function (clinical, echocardiography, ECG), renal function (echography, CT, urea, creatinine, electrolytes), and neurological function (clinical, CT scan, MRI, EEG).

Direct laryngoscopy and tracheal intubation can be difficult (face, mouth, and neck anomalies); the use of nasal tubes can be impossible because of nose malformations and choanal atresia. Spontaneous respiration must be maintained at all times because face-mask ventilation may be difficult or impossible. A laryngeal mask airway should be available in case of failure to ventilate or inability to intubate the trachea. Fiberoptic equipments should be available. Perimedullar anesthesia is contraindicated in cases of neural tube defects. Perioperative cardiorespiratory and blood pressure measurement can be useful because of apnea and cardiac lesions. Pulse oximetry can be difficult (nail anomalies).

Prophylactic antibiotics should be used in cases of cardiac defect as indicated. Avoid nephrotoxic drugs in cases of renal failure. Avoid anesthetic drugs with a marked cardiovascular effect.