Early onset congenital diarrheas; single center experience

Importance of genetic sequencing studies in managing chronic neonatal diarrhea: a case report of a novel variant in the glucose-galactose transporter SLC5A1

Introduction

Congenital glucose-galactose malabsorption (CGGM) is a rare autosomal recessive disorder that primarily causes chronic intractable diarrhea. This study aims to describe the clinical history, laboratory profile, diagnostic workflow, and management of the first patient reported with CGGM in Mexico.

Methods

The case involves a Mexican female infant with recurrent admissions to the emergency room since birth due to chronic diarrhea.

Results

The infant was born at term by C-section with a birth weight of 3.120 kg and height of 48 cm for consanguineous parents. She had been breastfed until day 5 of her life when she presented lethargy, diarrhea, abdominal discomfort, and jaundice. During the first evaluation at the emergency room, the significant laboratory finding was blood tyrosine elevation; afterward, amino acid and succinylacetone determinations were obtained, discarding tyrosinemia. When admitted to the hospital, an abdominal ultrasound detected a duplex collecting system. At this time, rice formula was introduced to the patient. She was discharged with jaundice improvement, but diarrhea persisted. Several formula changes had been made from rice to extensively hydrolyzed casein protein to whey-based, with no clinical improvement; the patient still had 10-12 excretions daily. In the second hospitalization, the patient presented anemia, severe dehydration, hyperammonemia, and renal tubular acidosis. A next-generation sequencing panel for inborn errors of metabolism and congenital diarrhea was performed, identifying a homozygous variant in SLC5A1 (c.1667T > C). The diagnosis of CGGM was made at 3 months of age. The infant was initially treated with a modular galactose-glucose-free formula with oil, fructose, casein, minerals, and vitamins until a commercial fructose-based formula was introduced. This led to a complete resolution of diarrhea and improved nutritional status.

Discussion

Diagnosing CGGM is challenging for clinicians, and next-generation sequencing is a valuable tool for providing appropriate treatment. More detailed information on patients with this condition might lead to possible phenotype-genotype correlations. This case's primary clinical and biochemical findings were chronic diarrhea, anemia, jaundice, renal tubular acidosis, hyperammonemia, and initial hypertyrosinemia. Symptoms were resolved entirely with the fructose-based formula.

Congenital Rare Diseases Causing Persistent Diarrhea in the Newborn: A Single Center Experience

Congenital diarrheal disorders (CDDs) are a heterogeneous group of inherited diseases that typically occur in the first weeks of life or can present later in life after the introduction of different nutrients; they can cause life-threatening severe dehydration and electrolyte disturbances. This study was conducted to characterize the causes of monogenic CDDs, and their clinical consequences. Clinical characteristics of 31 patients with CDDs that occurred in the first month of life and lasted more than 2 weeks were analyzed retrospectively. The patients were divided into groups according to the current CDD classification. The rate of consanguinity among parents was 77.4%. Of the patients, 16 (51.6%) were female and 15 (48.4%) were male. The underlying genetic defect was determined in 26 (83.9%) patients. The most common etiologic factors were digestive disorders of food and absorption and transport of electrolytes (58.1%, 18/31) (most of them being carbohydrate malabsorption disorders, 12/18) and intestinal immune system disorders (9.6%, 3/31). Total parenteral nutrition (TPN) was given to 45.2% (14/31) of the patients. Mortality rate was 28.5% (8/28). In conclusion, early diagnosis and treatment of CDDs with high morbidity and mortality is extremely important in terms of prognosis. Clinical and laboratory findings, stool characteristics, histopathological findings and the effects of dietary therapy are the primary and most important steps that lead to accurate diagnosis. In addition, advanced diagnostic possibilities, including genetic analyses, are essential for diagnosing underlying diseases.