Prenatal and presymptomatic diagnosis of the Marfan syndrome using fluorescence PCR and an automated sequencer

[Marfan's syndrome and pregnancy]

The Marfan's syndrome is an autosomal dominant genetic disorder resulting in a diminished strength of connective tissue. The ocular, skeletal and cardiovascular systems are mostly at risk. Principal complications of the disease are aortic dilatation and the risk of acute dissection. Pregnancy increases this risk. Based on the experience of our obstetrics department and after reviewing medical literature, we have tried to establish guidelines for obstetric care adapted to pregnant patients affected by Marfan's syndrome. Women with aortic root > 40 mm should avoid pregnancy. In all cases B-adrenergic receptor blockers must be used as soon as possible. Because there is a 50% risk that offspring will inherit the syndrome, prenatal diagnosis should be suggested. In addition to usual pregnancy monitoring, echocardiography should be performed every 3 months as well as 2 months after delivery. No increase of obstetrical complications has been shown in these patients. Route of delivery also depends on the diameter of the aortic root: vaginal delivery is warranted if the aortic root is<40; cesarean section should be performed in the other cases. Thus, with appropriate supervision, women with Marfan's syndrome will tolerate pregnancy without any adverse effect.

[Marfan syndrome and pregnancy. Apropos of 4 cases]

OBJECTIVES

To create a follow-up protocol for pregnant patients with Marfan syndrome.

PATIENTS AND METHODS

We retrospectively reviewed the charts of patients who delivered in the Jeanne de Flandre University Hospital between June 1996 and June 1999. Four pregnant patients with Marfan syndrome were identified.

RESULTS

Three of these patients had Bentall procedure. One of them had vaginal delivery and the two others underwent cesarean section. One of these two patients developed aortic valve thrombus at 14 weeks of amenorrhea. The fourth patient did not have surgery and had two vaginal deliveries.

DISCUSSION

According to our results and after reviewing literature pregnant patients with Marfan syndrome were divided into two groups. The 1st group was comprised of patients who underwent Bentall procedure. The 2nd one was comprised of patients who did not undergo any surgical procedure. The possibility of vaginal delivery for patients who underwent Bentall procedure (one case) and the interest of Propanolol and anticoagulant treatment are emphasized.

CONCLUSION

The multivariant approach of pregnant patients with Marfan syndrome is stressed out with special reference to the potential complications of this syndrome such as aortic dissection and to the problems related to the anticoagulant treatment.

Six novel mutations of the fibrillin-1 gene in Korean patients with Marfan syndrome

BACKGROUND

Mutations in the FBN1 gene, encoding fibrillin-1, result in Marfan syndrome (MFS). According to previous reports, the mutations in FBN1 share certain characteristics in each family with variable penetrance and overlapping symptoms, even in the same genotype. In the present study, we report six novel mutations and evaluate the clinical significance of these nucleotide changes.

METHODS

To screen for nucleotide changes in all 65 exons of the FBN1 gene in 38 unrelated Korean patients, we performed polymerase chain reaction, single-strand conformational polymorphism (SSCP) and sequencing for the shift of the band in SSCP.

RESULTS

We identified six mutations: a 2253 del 7 b.p., N1043S, C1254S, L1421F, C1895R and S2662P.

CONCLUSIONS

These results suggest that many different mutations are responsible for MFS in the Korean population.

Prenatal diagnosis in congenital contractural arachnodactyly

Congenital contractural arachnodactyly (CCA) is a heritable connective tissue disorder caused by defects in the gene encoding fibrillin-2 (FBN2). People with CCA typically have a marfanoid habitus, flexion contractures, severe kyphoscoliosis, abnormal pinnae, and muscular hypoplasia. Because of the relative infrequency of the syndrome and its generally mild to moderate severity, prenatal diagnosis had not previously been sought. Here we report prenatal diagnosis in a family with CCA. Because the course of the disease in the proband was rather severe, she had requested genetic counseling as early as age 17. She delayed childbearing until prenatal diagnosis for CCA became possible. This decision was supported by her mother and later her husband. Because she shared the same genotype with her husband, genetic linkage analysis of this family did not alter the a priori 50% risk of having an affected child. The possibility of unambiguously ascertaining the affected status of a fetus homozygous for the tested FBN2 marker was sufficient for the family to pursue prenatal diagnosis. This case strongly points to the importance of informed decisions now that genetic testing is becoming commonplace.

Cardiac operations in children with Marfan's syndrome: indications and results

BACKGROUND

The development of new screening techniques for the early detection of Marfan's syndrome has prompted evaluation of the results of cardiac operations in children with this syndrome. The purpose of this study was to determine the surgical indications, operative results, and need for reoperation in children with Marfan's syndrome.

METHODS

From 1980 to 1996, 245 patients underwent cardiac operations for complications of Marfan's syndrome; 26 (11%) were less than 18 years of age. The mean age at the time of operation was 10.3 +/- 1 years (range, 8 months to 17 years); 18 of the patients were male. Indications for operation were aortic root dilatation (15 patients), mitral regurgitation (4 patients), aortic root dilatation and mitral regurgitation (6 patients), and aortic arch aneurysm (1 patient). Operations included aortic root replacement (15 patients), aortic root replacement and mitral repair (5 patients), aortic root replacement and mitral replacement (1 patient), mitral repair (3 patients), mitral replacement (1 patient), and arch aneurysm repair (1 patient). The mean aortic root diameter in patients undergoing aortic root replacement was 6.2 +/- 0.2 cm. Only 1 patient underwent ascending aortic dissection. RESULTS. There were no operative deaths. At a mean follow-up of 67.1 +/- 10.2 months, 8 patients required a second cardiac procedure (41% +/- 17% 10-year freedom from reoperation). Indications for further operations were distal aortic pathology (3 patients), aortic root dilatation after initial mitral operation (3 patients), failed mitral repair (1 patient), and homograft degeneration (1 patient). Risk factors for a second cardiac procedure were age less than 10 years at the time of the first operation (p < 0.003) and mitral regurgitation (p < 0.04). Overall, 25 (96%) of 26 patients have undergone aortic root replacement and 11 (42%) patients have undergone a mitral procedure. There have been 4 late deaths, all of presumed cardiac origin. The 10-year survival rate is 79% +/- 10%. All surviving patients are in New York Heart Association functional class I or II.

CONCLUSIONS

We conclude that (1) aortic root dilatation is the most common surgical indication in children with Marfan's syndrome, (2) mitral regurgitation is the second most common indication, (3) aortic dissection is unusual in children with Marfan's syndrome, and (4) careful follow-up is necessary, particularly in younger children, because more than half of all children with Marfan's syndrome require repeated cardiac operations within 10 years.