Author Information
Tejashree Bakre*, Gupta
AS**
(* Third Year Resident, ** Professor. Department of Obstetrics and
Gynecology, Seth G.S.
Medical College
and K.E.M Hospital ,
Mumbai ,
India
Abstract
A well
controlled, pregnant, diabetic
patient
with bad obstetric history was diagnosed with fetus having single umbilical
artery (SUA) and absent nasal bone. Quadruple marker test revealed low risk for
trisomy 21, 13, 18 and neural tube defects. Amniocentesis was done and fluid
was sent for karyotyping and FISH. FISH revealed no aneuploidy of chromosomes
13, 18, 21 and sex chromosomes. Karyotype revealed paracentric inversion of
chromosome 7.
Introduction
Inversions account for
about 10% of structural chromosomal aberrations, with pericentric inversions
being more common than paracentric rearrangements probably due to diagnostic
difficulties in the latter group. Pericenteric inversions and most frquently associated
with chromosome 2 . Incidence
reported is around 11% . Paracenteric inversions are frequently seen in chromosomes 7 and 3 (19% and 16%, respectively)[1]
Case Report
A 27 year old Gravida 3 with 2
spontaneous abortions and 38.3 weeks of
pregnancy, a
known case of diabetes mellitus on lifestyle modifications for the last 1 year
was referred to our hospital casualty on 1st April 2014 in view of
severe pre eclampsia. There were no pre monitory symptoms. BP on admission was
180/110 mmHg, there was mild pallor, bilateral pedal edema, knee jerks were
normal, chest was clear, uterus was full
term, relaxed with fetus in vertex presentation and regular fetal heart sounds.
On vaginal examination
cervical os was 1.5cm dilated, poorly effaced,
vertex presentation, station -3,
membranes were present. Urine albumin was nil.
Patient was diagnosed with gestational hypertension at 31 weeks at BP of 146/90
mm Hg and was started on T. Labetalol 100mg qid which was modified
to 100mg
bid 4 weeks later. Serological, biochemical and hematological
investigations
were done.
Tab Nifedipine 10 mmg 6 hourly was started. Injection Magnesium
sulphate was started by Pritchard regime and induction of labour was done after
all reports were found
to be normal. HbA1c in the second month of pregnancy was 6.3% suggesting good
control of sugars. She was evaluated in private for bad obstetric history for
previous two spontaneous first trimester abortions. TORCH titres were negative
for IgM antibodies. Lupus anticoagulant and anti cardiolipin antibodies both
IgM and IgG were negative. Thrombophilia profile was within normal limits. A
malformation scan done at 21 weeks gestation revealed an absent nose and a
single umbilical artery. A quadruple marker test was done in view of single umbilical
artery which revealed low risk for trisomy 21, trisomy 18 and neural tube
defects. Subsequently amniocentesis was
done and amniotic fluid was sent for karyotyping and FISH tests. No aneuploidy
was detected for chromosomes 13, 18, 21 and sex chromosomes on FISH. This was
done on interphase nuclei.
Figure 1: FISH Report.
Karyotyping was done. It
diagnosed paracentric inversion of chromosome 7. This was a report
written on her case records. Patient did not have the mapped karyotype document
with her. Parental
karyotyping was done. It revealed normal
karyotype. She had uneventful antenatal course till term. She delivered a
female child of 2.075 kg weight, by face to pubis vaginal delivery. It was a
fresh still birth. Baby had absent nose, hypertelorism, laryngeal stenosis and
single umbilical artery.
Figure 2: Baby showing
Facial Dysmorphia. N: indicates the absent nose. Hypertelorism (widely
spaced eyes) is clearly seen.
Discussion
Statistics
suggest that the nasal bone can be absent in normal foetuses (chromosome
component normal) in 3% of the cases with an absent nose. In two thirds of
fetuses with trisomy 21 the nasal bone is absent.[2] Single
umbilical artery is a risk factor for structural and chromosomal abnormalities.[3] One third of the
foetuses have structural abnormalities and about 10% foetuses have chromosomal
anomalies (aneuploidy) like trisomy 13, and 18. Trisomy 21 is not found to be
associated with a single umbilical artery (SUA).[4]
When
sonography diagnosed the absent nasal bone and SUA the patient was evaluated by
a quadruple marker test to determine the risk of trisomy 21, 18 and neural tube
defects. An amniocentesis was done as the quadruple test returned a low risk
result for aneuploidy. A quadruple test is not recommended as per existing
scientific evidence in such cases.[5] Karyotyping is recommended
when a patient with single umbilical artery also shows intrauterine growth
retardation, or any structural abnormality.[5] The amniotic fluid
obtained by amniocentesis was sent for karyotyping and FISH. Karyotyping
diagnosed a paracentric inversion of
chromosome 7. FISH was normal.
Paracentric
inversion of chromosome 7 can have varied clinical presentations. Syndromes
like Michelin tire , Williams-Beuren, ectrodactyly-ectodermal dysplasia-cleft
syndromes have been described in literature in association with paracentric
inversion of chromosome 7. In all of
these syndromes there is facial dysmorphia, developmental and behavioural
disorders In "Michelin tire syndrome" there is hirsutism, smooth
muscle hamartoma, facial dysmorphia, submucous cleft palate, genital and dental
anomalies, seizures and moderate developmental delay. But in our case only few
of these features were noted. A peculiar feature of this syndrome is that the
baby and mother have apparently identical paracentric inversions of the long
arm of chromosome 7.[6] However in our case parental karyotyping was
normal. Normal parental karyotyping is commonly associated in cases of
congenital absence of nose as these cases are usually sporadic. Literature describes two cases with absent
nose involved chromosome 9 anomalies, and in a third case there was de novo
reciprocal translocation between chromosomes 3q and 12p.[7]
However chromosome 7 anomalies have not been reported to be associated with
congenital absence of nose.
Antenatal diagnosis of total arrhinia based on ultrasonographic findings has been described. Arhinia per se is not life threatening but the immediate and long-term outcomes of the neonate are dependent on associated anomalies. The afflicted neonate may need emergency resuscitation due to respiratory distress. In this case there was laryngeal stenosis which was the probable cause of death. The technique and timing of the reparative procedures of the nasal structures is also a medical controversy. Parental counselling is important. A multidisciplinary team effort is required for best neonatal results.[7]
Antenatal diagnosis of total arrhinia based on ultrasonographic findings has been described. Arhinia per se is not life threatening but the immediate and long-term outcomes of the neonate are dependent on associated anomalies. The afflicted neonate may need emergency resuscitation due to respiratory distress. In this case there was laryngeal stenosis which was the probable cause of death. The technique and timing of the reparative procedures of the nasal structures is also a medical controversy. Parental counselling is important. A multidisciplinary team effort is required for best neonatal results.[7]
References
- Muss B and Schwanitz G: Characterization of Inversions as a Type of Structural Chromosome Aberration: International Journal of Human Genetics, 200;7(2):141-161.
- Cicero S, Longo D, Rembouskos G : Absent nasal bone at 11–14 weeks of gestation and chromosomal defects : Ultrasound Obstet Gynecol 2003;22: 31–35
- Onofriescu M, Nemescu D, Martiniuc V: 21st World Congress on Ultrasound in Obstetrics and Gynecology Oral poster abstracts OP04.06 Prenatal echographic diagnosis of single umbilical artery Ultrasound in Obstetrics & Gynecology 2011;38 (Suppl 1):56–167.
- Geipel A , Germer U, Welp T: Prenatal diagnosis of single umbilical artery: determination of the absent side, associated anomalies, Doppler findings and perinatal outcome : Ultrasound in Obstetrics & Gynecology: 2000;15(2),114–117.
- Nyberg D, Nyberg B, McKenna C : : 21st World Congress on Ultrasound in Obstetrics and Gynecology Oral poster abstracts OP04.04 Absent or near absent nasal bone in the 2nd trimester :Ultrasound in Obstetrics & Gynecology 2011; 38 (Suppl. 1): 56–167.
- Schnur R, Herzberg A, Spinner N : Variability in the Michelin tire syndrome. A child with multiple anomalies, smooth muscle hamartoma, and familial paracentric inversion of chromosome 7q. : Journal of the American Academy of Dermatology 03/1993; 28(2 Pt 2):364-70.
- Merino A, De Perdigo A, Nombalais F, Yvinec M, Le Roux MG, Bellec V. Prenatal diagnosis of trisomy 9 mosaicism: two new cases. Prenat Diagn. 1993 Oct; 13(10):1001-7.
Bakre T, Gupta AS. Fetal
Nasal Agenesis. JPGO 2014
Volume 1 Number 8. Available from: http://www.jpgo.org/2014/08/author-information-tejashree-bakre.html