Perinatology.  2017 Jun;28(2):59-68. 10.14734/PN.2017.28.2.59.

Comparison of Two Congenital Myotonic Dystrophy Groups According to the Number of CTG Trinucleotide Copies on Clinical Characteristics and Outcomes

• Hwang IJ
• Lee HO
• Oh HJ
• Song ES
• Choi YY

• KMID: 2386354
• DOI: http://doi.org/10.14734/PN.2017.28.2.59

Abstract

OBJECTIVE
The aims of this study were to compare clinical characteristics and outcome of neonates with congenital myotonic dystrophy (CMD) according to the number of cytosine, thymine, guanine (CTG) copies and to analyze the relating factors for survival.
METHODS
The patients were divided into two groups; less than or equal to 1,000 CTG copies (group A) and above 1,000 CTG copies (group B). This study compared the maternal CTG copies, obstetric characteristics, and patients' clinical characteristics, morbidity, hospital course, and long term outcome between group A and B, and also analyzed the relating factors for survival.
RESULTS
The twenty-three patients were confirmed by gene analysis in the neonatal period. Nine patients (39.1%) were included in group A and fourteen patients (60.9%) in group B. There was no correlation between the number of CTG copies of the mothers and their babies. There were no significant differences in maternal obstetric characteristics, patient's clinical findings, morbidities, hospital course and mortality between group A and B. Seven patients died before discharge and six patients among 16 who survived died after discharge. Analyzing the relating factors for survival, Apgar score at 1 and 5 minute were significantly higher in patients who survived than those who expired (P=0.0001, P=0.01, respectively). All survived patients showed developmental delay and 7 patients (58.3%) failed to thrive.
CONCLUSION
There was no correlation between the number of CTG copies of the mothers and their babies. There were no statistical differences in maternal obstetric characteristics, patient's clinical findings, morbidities, hospital course, and mortality between the two groups. Apgar score at 1 minute and 5 minute were the relating factors for survival.

Keyword

Myotonic dystrophy; CTG trinucleotide copies number; Outcomes

MeSH Terms

Apgar Score
Cytosine
Guanine
Humans
Infant, Newborn
Mortality
Mothers
Myotonic Dystrophy*
Thymine
Cytosine
Guanine
Thymine

Figure

• 

  Fig. 1 Southern blot of long-range PCR products from the CTG copies in the DMPK gene. (A) More than 1,000 CTG copies expansion (patient of case 12), (B) 75 of CTG copies expansion (mother of case 12). The arrow indicate subject's strand of PCR products. PCR, polymerase chain reaction; CTG, cytosine, thymine, guanine; M, gene ruler-size marker; NC, normal control; PC, positive control; Sub, subject.

• 

  Fig. 2 Flow diagram of subjects. CMD, congenital myotonic dystrophy; CTG, cytosine, thymine, guanine.

• 

  Fig. 3 The relationship between CTG copies of patients and their mothers. CTG, cytosine, thymine, guanine.

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