Insights into Central Congenital Hypothyroidism: A Multicenter Retrospective Analysis.

CONTEXT: Central congenital hypothyroidism (CCH) is a thyroid hormone deficiency at birth caused by inadequate pituitary stimulation of the thyroid gland. Although primary CH has been studied extensively, studies on CCH are sparse. OBJECTIVES: To assess the prevalence of CCH in Israel and describe its clinical features, neonatal screening results, and outcomes. DESIGN: Multicenter cross-sectional retrospective chart review. SETTING: Nine pediatric endocrine units throughout Israel. PATIENTS: Patients diagnosed with CCH in 1987-2021 were categorized into early (within 14 days of life) and late (after 14 days) diagnosis groups. Newborn screening (NBS) results were retrospectively retrieved from the national NBS program dataset. RESULTS: CCH prevalence in Israel was about 1:42,800 live births. Subjects were 94 patients (54 males), of these, 84% had multiple pituitary hormone deficiencies and 16% had isolated CCH. The median age at diagnosis was 50 days (range, 1-8760), with 66% having moderate to severe hypothyroidism. NBS detected only three infants. Early diagnosis occurred in 34% due to hypopituitarism, while 66% were diagnosed later due to growth and developmental delays. Neurodevelopmental sequelae included mental retardation (12%), learning difficulties (18%), delayed speech (27%), and motor clumsiness (19%), with no significant differences in outcomes between early and late diagnosis. CONCLUSIONS: Despite high rates of neurodevelopmental sequelae, no differences were found between early and late diagnosis groups. Further research is needed to assess the impact of delayed diagnosis on neurological outcomes in newborns with CCH. Improved strategies for detecting CHH in newborns are also necessary.

The natural history of dihydrolipoamide dehydrogenase deficiency in Israel.

Dihydrolipoamide dehydrogenase (DLD) deficiency is an ultra-rare autosomal-recessive inborn error of metabolism, affecting no less than five mitochondrial multienzyme complexes. With approximately 30 patients reported to date, DLD deficiency was associated with three major clinical presentations: an early-onset encephalopathic phenotype with metabolic acidosis, a predominantly hepatic presentation with liver failure, and a rare myopathic phenotype. To elucidate the demographic, phenotypic, and molecular characteristics of patients with DLD deficiency within the Israeli population, data were collected from metabolic disease specialists in four large tertiary medical centers in the center and south of Israel. Pediatric and adult patients with biallelic variants in DLD were included in the study. A total of 53 patients of 35 families were included in the cohort. Age at presentation ranged between birth and 10 years. Wide phenotypic variability was observed, from asymptomatic individuals in their sixth decade of life, to severe, neonatal-onset disease with devastating neurological sequelae. Six DLD variants were noted, the most common of which was the c.685G>T (p.G229C) variant in homozygous form (24/53 patients, 45.3%; 13/35 families), observed mostly among patients of Ashkenazi-Jewish descent, followed by the homozygous c.1436A>T (p.D479V) variant, found in 20 patients of Bedouin descent (37.7%; 16/35 families). Overall, patients did not necessarily present as one of the previously described distinct clinical phenotypes. DLD deficiency is a panethnic disorder, with significant phenotypic variability, and comprises a continuum, rather than three distinct clinical presentations.