To demonstrate the prevalence of maternal mosaic monosomy X (MMXO) in a cohort of pregnant women in Vietnam.
All 105,594 singleton pregnant women undergoing noninvasive prenatal screening (NIPS) ...between January 2019 and February 2021 in Vietnam were analyzed by measuring discordance between size- and count-based z-scores for chromosome X (ChrX) to identify suspected cases of MMXO and validated by fluorescence
hybridization (FISH) on maternal blood.
We identified 295 (0.279%) suspected MMXO cases. After FISH analysis, MMXO was confirmed in 125 cases (42.37%), revealing the MMXO prevalence of 0.118% (95% CI: 0.097-0.139%) in this cohort.
We found a relatively high prevalence of MMXO in Vietnamese pregnant women and demonstrated a strong influence of MMXO on the ChrX z-score using a count-based method, resulting in false positives. The size-based method is not sensitive to MMXO and therefore achieves higher PPV.
Vietnam has a high thalassemia burden. We collected blood samples from 5880 pregnant Vietnamese women during prenatal health checks to assess thalassemia carrier frequency using combined ...gap-polymerase chain reaction (gap-PCR) and targeted next-generation sequencing (NGS). Thalassemia carriers were identified with prevalence of 13.13% (772), including 7.82% (460) carriers of α-thalassemia (α-thal), 5.31% (312) carriers of β-thalassemia (β-thal), and 0.63% (37) concurrent α-/β-thal carriers. Deletional mutations (368) accounted for 80.0% of α-thal carriers, of which, --
SEA
(Southeast Asian) (n = 254; 55.0%) was most prevalent, followed by the -α
3.7
(rightward) (n = 66; 14.0%) and -α
4.2
(leftward) (n = 45; 9.8%) deletions. Hb Westmead (HBA2: c.369C>G) (n = 53) and Hb Constant Spring (Hb CS or HBA2: c.427T>C) (in 28) are the two most common nondeletional α-globin variants, accounting for 11.5 and 6.0% of α-thal carriers. We detected 11 different β-thal genotypes. Hb E (HBB: c.79G>A) (in 211) accounted for 67.6% of β-thal carriers. The most common β-thal genotypes were associated with mutations at codon 17 (A>T) (HBB: c.52A>T), codons 41/42 (-TTCT) (HBB: c.126_129delCTTT), and codon 71/72 (+A) (HBB: c.217_218insA) (prevalence 0.70%, 0.68%, and 0.2%, respectively). Based on mutation frequencies calculated in this study, estimates of 5021 babies in Vietnam are affected with clinically severe thalassemia annually. Our data suggest a higher thalassemia carrier frequency in Vietnam than previously reported. We established that combining NGS with gap-PCR creates an effective large-scale thalassemia screening method that can detect a broad range of mutations.
To demonstrate the prevalence of maternal mosaic monosomy X (MMXO) in a cohort of pregnant women in Vietnam.
All 105,594 singleton pregnant women undergoing noninvasive prenatal screening (NIPS) ...between January 2019 and February 2021 in Vietnam were analyzed by measuring discordance between size- and count-based z-scores for chromosome X (ChrX) to identify suspected cases of MMXO and validated by fluorescence in situ hybridization (FISH) on maternal blood.
We identified 295 (0.279%) suspected MMXO cases. After FISH analysis, MMXO was confirmed in 125 cases (42.37%), revealing the MMXO prevalence of 0.118% (95% CI: 0.097-0.139%) in this cohort.
We found a relatively high prevalence of MMXO in Vietnamese pregnant women and demonstrated a strong influence of MMXO on the ChrX z-score using a count-based method, resulting in false positives. The size-based method is not sensitive to MMXO and therefore achieves higher PPV.
The southern white-cheeked gibbon
Nomascus siki
is endemic to Indochina and is classified as critically endangered on the International Union for Conservation of Nature (IUCN) Red List. The most ...updated information on the status of this species dates back to a decade ago. As hunting has tremendous impacts on wildlife in Southeast Asia, the population of
N. siki
might have changed a lot in the last decade. Updated information on the status and potential distribution of this species is critically important for conservation and prioritization, especially for
N. siki
because of its undefined distribution range. The goal of this study was to review the population status of
N. siki
in Vietnam and Lao People's Democratic Republic (PDR) and to model its potential distribution. In Vietnam, this species has been intensively surveyed in all major areas of occurrence from 2016 to 2021. The total number of
N. siki
groups recorded and estimated in Vietnam were 324 and 483, respectively. In Lao PDR, the occurrence of
N. siki
has been confirmed in Nam Kading, Nakai Nam Theun, Hin Nam No, and Phou Hinpoun national protected areas. However, population estimates are generally lacking. The suitable habitat of
N. siki
was predicted from about 105.00° to 106.80° E longitude and from about 16.60° to 17.90° N latitude located in Quang Binh and Quang Tri provinces (Vietnam), and Khammounan and Savannakhet provinces (Lao PDR). The area of the potential distribution range is about 9894.15 km
2
, both in Vietnam and Lao PDR. Particularly, the high, medium, and low suitable habitats were estimated at around 1229.58 km
2
, 3019.68 km
2
, and 5644.89 km
2
, respectively. The area of suitable habitat of
N. siki
in Vietnam was predicted to be 4151.25 km
2
, of which only 1257.93 km
2
(30.30%) is in the protected area network. Dong Chau–Khe Nuoc Trong and Bac Huong Hoa Nature Reserves, and Phong Nha–Ke Bang National Park should receive priority for conservation of
N. siki
in Vietnam. Improving conservation beyond the protected areas’ boundaries or transforming the forest enterprises and watershed protection forests into protected areas should also be considered as an alternative for the conservation of
N. siki
. In Lao PDR, surveys of the species in its entire distribution range should be the first priority.
