Clinical management considerations in long-term survivors with trisomy 18. Pediatrics.1990; 85(5):753-759.

As many as 90% or more of children with trisomy 18 die within the first year of life. A review of six patients with trisomy 18 documented by karyotype surviving past 1 year of age and of the trisomy 18 files of the Support Organization for Trisomy 18 and 13 indicated that a small number of children with trisomy 18 survive beyond their first year of life; a few live into their teens and twenties. In addition to medical problems that are unique to this chromosomal syndrome, these patients present complex medical problems common to all persons with chromosomal anomalies. The primary and tertiary care consultants who are able to provide knowledge and sensitive supportive care to children with trisomy 18 and to their parents are performing a service of significant benefit, no matter how brief the life span of the child may be.

Thirty-one autopsy cases of trisomy 18: clinical features and pathological findings. Pediatr Pathol.1989;9(4):445-457.

The clinical features and morphological findings in 31 Japanese infants with trisomy 18 are presented. The majority were small-for-date infants. There was no sex predominance in our series, as opposed to male: female ratios of 1:3 reported in the literature. The average age at death was greater in females than in males. Cardiovascular anomalies were consistently present; ventricular septar defect and patent ductus arteriosus being the most common malformations. Various other internal malformations including the Arnold-Chiari malformation were observed.

Edwards syndrome with double trisomy.Singapore Med J. 2008 Jul;49(7):e190-1.

Double trisomy is rare and the only case reported in the literature died soon after birth. We present another case of double trisomy (48XYY, +18) in a male neonate, who was born to a 28-year-old gravida three parity one mother at 35 weeks of gestation. The baby had features of trisomy 18. Karyotype of the patient showed 48, XYY, +18, Ish (DYZ3*2), (D18Z1*3), nuc ish (DYZ3*2), (D18Z1*3) . The patient had clinical features of trisomy 18. There was no family history of diabetes mellitus and no exposure to chemicals. It has been suggested that the rarity of Y-chromosome involvement in trisomy 18 may be due to discrepancy between the sexes.

Upper limb abnormalities as an isolated ultrasonographic finding in early detection of trisomy 18. A case report. Fetal Diagn Ther. 2003 Nov-Dec;18(6):401-3.

Trisomy 18 is the second most common multisystem malformation syndrome. We present here a case of a fetus with trisomy 18, in which upper limb reduction was detected prenatally, as an isolated defect, at 17 weeks of gestation. The pregnancy was terminated by vaginal administration of misoprostol, and postmortem examination confirmed the ultrasound findings, including bilateral upper limb reduction with radial aplasia, absent first metacarpal and thumb and ventrally hyperflexed hands. This case demonstrates the need for thorough ultrasound evaluation of the fetal hands, as early as possible, because upper limb deformities can be the only abnormality of trisomy 18.

Fronto-nasal dysplasia and atrio-ventricular canal in a fetus with trisomy 18 identified by absent nasal bones during first trimester screening scan.Congenit Anom (Kyoto). 2007 Mar;47(1):45-8.

Failed ultrasonographic visualization of nasal bones is associated with an increased risk of fetal malformations. Maternal ethnicity and chromosomal abnormalities influence the incidence and visualization rate of nasal bones. A case of absent nasal bones with fronto-nasal dysplasia and septated cystic hygroma identified at 13(+5) weeks' gestation in a trisomy 18 fetus is reported. The crown-rump length was 82 mm and the absent nasal bones were associated with micrognathia and a flattened face. The risks for trisomy 21 and 18 were subsequently calculated. The couple refused chorionic villus sampling. At 19 weeks' gestation a follow-up scan revealed, apart from the resolution of septated cystic hygroma, hypertelorism, a large interventricular septum defect with an atrio-ventricular canal and an abnormal A wave Doppler pulsation at the level of the ductus venosus. Bilateral choroid plexus cysts were additional ultrasound findings. At that time, an uneventful cordocentesis was performed showing a 47,XY(+18) karyotype. Termination of pregnancy was achieved and pathologic examination confirmed the ultrasonographically detected fetal malformations. When screening the fetal face for the presence or absence of nasal bones during the first trimester pregnancy scan the following points must be taken into consideration: (i) the ethnicity of the mother; (ii) if the nasal bones are absent, measurement of nuchal translucency and risk calculations for trisomy 21 and trisomy 18 should be performed; (iii) if the calculated risks are high, karyotyping should be recommended; and (iv) determine whether the absent nasal bones are an isolated or an associated finding and, in the latter case, discriminate between minor or major fetal malformations.

Anatomical analysis of the developmental effects of aneuploidy in man--the 18-trisomy syndrome: II. Anomalies of the upper and lower limbs. Am J Med Genet 1978;2(3):285-306.

We report the anatomical variations of the limbs in eight infants with the trisomy-18 syndrome that were dissected and studied in detail. In each case, the upper limbs showed defects which further define the specific influence of this aneuploidy on the development of its preaxial (radial) component, and the tendency towards reduction defects. Abnormalities included muscle variations concentrated along the radial margin of the forearm and hand, the absence of the definitive musculocutaneous nerve in all of the limbs, and reductions of the radial artery in four of the bodies. Pathogenetic mechanisms explaining the observed defects are discussed, and include: 1) a defect in peripheral nerve development; or 2) tissue necrosis. The characteristic flexion deformities of the fingers seem to be due to a displacement of the tendons of extensors digitorum and digiti minimi. The lower limbs did not show a consistent pattern of defects, except for the absence of some muscles (psoas minor, the tendon of flexor digitorum brevis to digit V), and the presence of several supernumerary muscles. These variations are discussed as possible nonspecific effects of 18-trisomy on development. The additional anatomical data from this and the first paper in this series [Bersu and Ramirez-Castro, 1977] provide a more detailed picture of the trisomy-18 phenotype which may be useful in corroborating an unconfirmed clinical diagnosis of the syndrome.