Alobar holoprosencephaly associated with a rare chromosomal abnormality: Case report and literature review

Alobar holoprosencephaly in mining-related areas of the Eastern region of the Democratic Republic of the Congo: A case series

BACKGROUND

Recent case reports described three cases of holoprosencephaly (HPE) in the area with high mining-related pollution of the southern region of the Democratic Republic of the Congo (DRC). We reported two male neonates with clinically diagnosed HPE in the localities of Fizi and Kitutu, two mineral areas in the Eastern region of the same country (DRC), where artisanal surface mining is predominant with high exposure to radiation and heavy metals from mining.

CASES' PRESENTATIONS

Two newborns from adult and multigravida mothers without pregnancy complication. The birth weights were 3,200 g and 2,500 g, respectively, and the malformations noticed were essentially the single median eye, the absent nose, polydactyly for one case, and proboscis for the other case. They both died a few minutes later after birth.

CONCLUSION

The etiologic factors of HPE remain unknown but seem to be multifactorial from both genetic and environmental factors. We hypothesize under reserve for these two cases that mining and radiation expositions were likely potential environmental associated factors to the occurrence of these malformations.

Prenatal diagnosis of syndromic alobar holoprosencephaly associated with digynic triploidy fetus

Holoprosencephaly (HPE) is a dramatic human brain malformation sequence with an extreme variable phenotypic spectrum and genetic heterogeneity, variable degree of severity and unknown etiology, in many cases. HPE is classified into syndromic, chromosomal, and non-syndromic, non-chromosomal. The most cases of HPE are syndromic. We present an atypical case of syndromic alobar HPE associated with digynic triploidy fetus, prenatally diagnosed, early at 18 weeks of gestation, by ultrasound (US) and complex genetic investigations. The US examination was performed with a specialized US machine, General Electric Voluson E10 OLED BT18, using two-dimensional (2D) scanning, three-dimensional (3D) image reconstruction, four-dimensional (4D) spatiotemporal image methodology and the highest power Doppler US technology. A detailed US examination of the fetus revealed several major abnormalities of the fetal head and severe facial malformations. Based on the antenatal US findings, the fetus was diagnosed with alobar HPE. After a careful examination and genetic counseling, additional cytogenetic investigations and molecular genetic analyses were performed, which revealed an abnormal number of 69 chromosomes, digynic triploidy (69,XXY). Two days later, the parents choose to interrupt the current gestation because of major fetal malformations. The pathological examination of the embryo reaffirmed the antenatal diagnostics.

Case Report of a Term Newborn with Prenatally Diagnosed Alobar Holoprosencephaly

Holoprosencephaly is a congenital structural abnormality of brain resulting from incomplete cleavage of prosencephalon into two cerebral hemispheres. It is classified as a disorder of organogenesis and brain histogenesis and is typically associated with facial anomalies.

Holoprosencephaly is relatively rare – the incidence in live births varies between 1:10,000 – 1:15,000 but is described in 1 out of 250 spontaneously aborted embryos.

There are four major varieties of holoprosencephaly according to the degree of separation of the brain hemispheres; this division is crucial for the patient’s prognosis. Three classic subtypes are alobar, semilobar, and lobar holoprosencephaly and there is also a fourth subtype called middle interhemispheric variant.

We present a case study of a term newborn with prenatally diagnosed holoprosencephaly with severe facial dys-morphism and associated health complications.

Umbilical cord lactate compared with pH as predictors of intrapartum asphyxia

Despite advances in fetal monitoring during labor, one of the most critical causes of neonatal death and neurologic injuries remains intrapartum asphyxia. Umbilical cord gases can be used to detect acidosis and fetal distress. We conducted a retrospective, multicenter study to evaluate umbilical cord blood pH and lactate as a mean of evaluating the degree of intrapartum hypoxia and also to establish which of the two is more reliable in predicting morbidity in term neonates. The present study utilized a total of 124 cases that met the criteria for intrapartum asphyxia and 150 normal term newborns that were randomly selected as case control. Both umbilical cord lactate and pH proved to be accurate predictors of neonatal morbidity caused by intrapartum hypoxia. Lactate proved to be superior to pH in predicting adverse neonatal outcome. The greatest sensibility and specificity in predicting intrapartum asphyxia were achieved in our study by using a cutoff value of 3.75 mmol/l for lactate and 7.24 for pH.

Prenatal ultrasound findings of holoprosencephaly spectrum: Unusual associations

OBJECTIVE

The objective of this study is to evaluate the prenatal diagnosis, postnatal characteristics, and the spectrum of associated findings in fetuses with holoprosencephaly (HPE).

METHODS

Fetal neurosonograms, postnatal assessment, and chromosomal analysis were performed in a cohort of 25 fetuses with HPE.

RESULTS

The prevalence of HPE in high-risk pregnancies was 4.4:10 000. The alobar subtype was the most frequently encountered, with 17 cases (68%). Interestingly, among them, four cases (16%) presented with the rare agnathia-otocephaly complex. Chromosomal abnormalities were detected in 11 cases (44%), the most frequent being trisomy 13 in seven cases (five alobar, one semilobar, and one lobar HPE), followed by trisomy 18 in two cases with semilobar HPE. One case of alobar HPE had 45, XX, t(18;22) (q10;q10), -18p karyotyping, and one case of semilobar HPE was associated with triploidy. Facial malformations in HPE spectrum ranged from cyclopia, proboscis, and arrhinia that were associated with the alobar subtype to hypotelorism and median cleft that were frequent among the semilobar and lobar subtypes. Associated neural tube defects were identified in 12% of cases.

CONCLUSION

Our study illustrates the clinical and genetic heterogeneity of HPE and describes different chromosomal abnormalities associated with HPE.