Abstract Transient neonatal tyrosinemia (TNT) is a form of hypertyrosinemia produced by the immaturity of 4-hydroxyphenylpyruvate dioxygenase (4-HPPD), a high intake of phenylalanine and tyrosine, and a relative ascorbic acid deficiency. Our objectives are to determine the incidence of TNT in Mexican newborns and to correlate it based on their sex, gestational age, and weight for gestational age to determine whether these are risk factors that predict the development of TNT. A cross-sectional descriptive study was conducted from January 2006 to August 2017. We analyzed 175 976 of newborn screening reports and found that the overall incidence of TNT was 1 (0.29%) in 342 newborns. It is more prevalent in preterm infants and in small for gestational age newborns (0.35%).The TNT incidence was determined in this Mexican population, and it was established as the most frequently occurring amino acid defect. We propose that pediatricians intentionally search for this pathology to offer patients access to adequate and timely treatment.

Abstract: Background: Multiple hereditary osteochondromatosis is characterized by the growing of benign cartilaginous tumors in form of exostosis, predominately in the metaphysis of long bones. It is described with a prevalence of 1/50,000 individuals. Case reports: This article presents the clinical information and its autosomal dominant inheritance pattern where exotoxin genes (EXT gene family) were affected in a three-member family with multiple hereditary osteochondromatosis. The three patients showed altered arcs of movement of wrists, shoulders and ankles. Clinical diagnosis was confirmed with radiology and malignancy was ruled out in all patients. Conclusions: This disease requires frequent medical evaluation, surgical bone correction when the normal function is involved, surveillance for malignant transformation, and genetic counseling.

Resumen: Introducción: La osteocondromatosis múltiple hereditaria se caracteriza por el crecimiento de múltiples tumores benignos, cartilaginosos, que crecen en forma de exostosis predominantemente en las metáfisis de los huesos largos. Se ha descrito una prevalencia de 1/50,000 individuos. Casos clínicos: Se presenta la información clínica y patrón hereditario autosómico dominante, en el que están afectados los genes de exostosina (familia de genes EXT) en tres miembros de una familia con osteocondromatosis múltiple. Los tres pacientes han presentado alteraciones en los arcos de movimiento de muñecas, hombros o tobillo. El diagnóstico clínico fue confirmado con estudios radiológicos y no hay evidencia de que las lesiones se hayan malignizado. Conclusiones: Esta entidad requiere de supervisión periódica, corrección quirúrgica de las deformaciones que limiten la función, vigilancia de la transformación maligna y consejería genética.

Abstract Newborn screening for the detection of inborn errors of metabolism (IEM), endocrinopathies, hemoglobinopathies, and other disorders is a public health initiative aimed at identifying specific diseases in a timely manner. Mexico initiated newborn screening in 1973, but the national incidence of this group of diseases is unknown or uncertain due to the lack of large sample sizes of expanded newborn screening (ENS) programs and lack of related publications. The incidence of a specific group of IEM, endocrinopathies, hemoglobinopathies, and other disorders in newborns was obtained from a Mexican hospital. These newborns were part of a comprehensive ENS program at Ginequito (a private hospital in Mexico), from January 2012 to August 2014. The retrospective study included the examination of 10 000 newborns’ results obtained from the ENS program (comprising the possible detection of more than 50 screened disorders). The findings were the following: 34 newborns were confirmed with an IEM, endocrinopathies, hemoglobinopathies, or other disorders and 68 were identified as carriers. Consequently, the estimated global incidence for those disorders was 3.4 in 1000 newborns; and the carrier prevalence was 6.8 in 1000. Moreover, a 0.04% false-positive rate was unveiled as soon as diagnostic testing revealed negative results. The most frequent diagnosis was glucose-6-phosphate dehydrogenase deficiency; and in the case of carriers, it was hemoglobinopathies. The benefit of the ENS is clear as it offers prompt treatment on the basis of an early diagnosis including proper genetic counseling. Furthermore, these results provide a good estimation of the frequencies of different forms of newborn IEM, endocrinopathies, hemoglobinopathies, and other disorders at Ginequito.