Pediatric Medical Genetics - S.I. Smiian 2003

Chromosomal diseases
Patau syndrome

Full trisomy 13 was described in 1960, almost immediately after the discovery of trisomy 21, and has since remained the second most frequent complete autosomal trisomy. The incidence of this syndrome ranges from 1:5000 to 1:8000 live births. Affected infants are more commonly born to older mothers.

The physical appearance of patients with Patau syndrome is quite distinctive. Newborns typically present with normal birth weight and dimensions. Clinically, they exhibit symptoms of Central Nervous system underdevelopment, microcephaly, malformed and low-set ears, ocular anomalies (microphthalmia and anophthalmia), unilateral or bilateral cleft lip and palate, polydactyly, joint hypermobility, and Congenital Malformations of Internal Organs (cardiovascular, urinary, and digestive systems), with seizures being frequently observed.

Other notable Clinical Features include capillary hemangiomas of the fingers, FOOT deformities, umbilical and inguinoscrotal hernias, cryptorchidism, and deafness. Hearing loss occurs in approximately 80% of patients with trisomy 13, most commonly involving structural alterations of the Middle ear and the lower portion of the Inner ear.

Trisomy 13 is characterized by high early mortality. Approximately 90% of affected children die within the first year of life, while the remaining patients succumb within the first few years.

It is important to note that both translocation and trisomy Variants of the syndrome exist; therefore, a definitive Diagnosis can only be established through cytogenetic analysis. In cases of the translocation variant, the recurrence risk for having another affected child reaches 25%, whereas for the trisomy variant, it is only 1-2%.

There are currently no effective treatments for Patau syndrome.