Clinical relevance of cytogenetics to pediatric practice. Postnatal findings of Patau syndrome - Review of 5 cases

Abstract

Introduction: Patau syndrome (trisomy 13) is one of the most common chromosomal anomalies clinically characterized by the presence of numerous malformations with a limited survival rate for most cases. Babies are usually identified at birth and the diagnosis is confirmed with genetic testing.

Materials and methods: In this review we outline the clinical and cytogenetic aspects of trisomy 13 and associated phenotypes for 5 cases analyzed in the last 3 years, referred to our Clinical Genetics Department. For each child cytogenetic analysis was performed to determine the genetic variant; also, the patients were investigated for other associated malformations (cardiac, cerebral, renal, ocular anomalies).

Discussion: All 5 cases presented multiple malformations, including some but not all signs of the classical clinical triad suggestive of Patau syndrome. The cytogenetic investigation confirmed for each case the suspected diagnosis and also indicated the specific genetic variant, this being a valuable information for the genetic counselling of the families.

Conclusion: The application of genetic analysis can increase diagnosis and prognosis accuracy and have an impact on clinical management.

Keywords: Patau syndrome; cleft palate; genetics; microphthalmia; polydactyly; trisomy 13.

A.

a) free trisomy 13 with the idiogram of G-banding pattern for normal chromosome 13 (cases 1,3 and 4);

B.

b) Robertsonian translocation t (13;14) with corresponding idiogram (case 5);

C.

c) partial trisomy 13 with idiogram of the derivative chromosome 13 (case 2)

Figure 2

Postaxial polydactyly of the left hand

Figure 3

Vertex alopecia

Figure 4

Cleft palate

Figure 5

Short palpebral fissures, bulbous nose

Figure 6

Practical steps for the evaluation of a patient suspected to have trisomy 13