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Page 4 of 10 Gonzaga-Jauregui et al. Rare Dis Orphan Drugs J 2024;3:16 https://dx.doi.org/10.20517/rdodj.2024.02

result for any of the six lysosomal storage conditions was obtained in 1 in 1,212 newborns and CHT was
identified in 1 in 2,128 newborns. The most frequent lysosomal storage disease identified by ENBS was
Pompe pseudodeficiency, followed by late-onset renal Fabry disease due to a founder variant (p.Arg363His)
[7]
in the GLA gene in the Mexican population . Early identification of newborns with these conditions
through the ENBS program at PEMEX has enabled improved disease management and timely therapeutic
interventions through dietary substitution and supplementation, with positive outcomes observed through
longitudinal follow-up at PEMEX.

Healthcare services for military members and their dependents are provided by either SEDENA (Secretaría
de la Defensa Nacional) or for navy members by the SEMAR (Secretaría de Marina). Both of these
institutions have implemented ENBS and screened newborns for more than 60 conditions as part of their
programs. Results of SEMAR’s ENBS program showed a prevalence of 1 in 651 newborns with a genetic
disorder in their population, with an ENBS coverage of 99.4% of all births in their system. The most
[8]
prevalent conditions detected were G6PDD, followed by CHT and CAH .

Since 2019, the Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE), one of
the major public healthcare systems in Mexico that serves State workers and their families throughout the
country, has implemented ENBS for 66 analytes and currently screens for 78 conditions. Disease prevalence
and findings to date for ISSSTE’s ENBS program have not been published yet. The other two major public
healthcare systems, Instituto Mexicano del Seguro Social (IMSS) and Secretaría de Salud (SS), which serve
the great majority of the Mexican population, screen for 7 and 6 conditions, respectively [Table 2].

More recently, advocacy efforts from the civil society, clinicians, and researchers have achieved the
implementation of ENBS in Mexican states beyond specific healthcare systems. The Mexican state of
Quintana Roo legislated in 2021 the implementation of ENBS for all newborns born in that state, while most
recently, in 2023, the state of Guanajuato followed suit [9,10] . Although similar to the national ENBS
guidelines, these reforms to the state health laws do not explicitly mention the number or list of conditions
to be screened for; however, the inclusion of ENBS as part of individual state health laws is important to
achieve national implementation. Additionally, since 2022, National Newborn Screening Day has been
officially recognized in Mexico every June 28th to raise awareness and increase education about it in the
country. Most recently and as part of these efforts to increase awareness and achieve improved
implementation and coverage, effective from July 2023, results for the five types of newborn screening
mandated for Mexican newborns, namely metabolic, hearing, visual, cardiac, and hip dysplasia, will be
[11]
included in the national vaccination card for all infants born in Mexico [Figure 1] . The national
vaccination card is an official government-issued document that tracks early development, wellness, and the
application of compulsory immunizations for children born in Mexico from 0 to 9 years of age. Of the
mandated screenings, only metabolic NBS/ENBS involves molecular confirmatory testing, while the other
types of screening are merely clinical and, similar to metabolic NBS, are not implemented consistently and
widely. Therefore, inclusion and mandatory report of results for these screenings are relevant to achieve
homogenization in the implementation of NBS across the healthcare institutions in Mexico, and ensure that
NBS is being performed for every infant born in the country regardless of parents’ employment or
healthcare provider affiliation.

[1]
The estimated coverage of basic NBS in Mexico was about 84% in 2018 ; however, a major disruption and
suspension of NBS occurred in 2019 due to problems with the Ministry of Health contracting in twelve
Mexican states. Although only newborns born in hospitals and medical units around the country are
[12]
screened, the uptake for institutional births is high in Mexico (> 90%), but this varies among states , with a