Report of a severe case of Allan-Herndon-Dudley syndrome

Allan-Herndon-Dudley syndrome (AHDS) is an X-linked neuromuscular disorder characterized by psychomotor retardation, intellectual disability, muscular hypotonia, feeding difficulties and neurological symptoms in boys.1 Diagnosis is mainly made through molecular genetic testing where a proband is established with relevant clinical findings and a pathogenic variant in hemizygosis in the SLC16A2 gene. We will describe the case of a 3-year-old boy who was initially referred to the medical genetics service to rule out trisomy 21, with significant global neurodevelopmental delay, severe hypotonia, recurrent respiratory infections, poor weight gain, reduced muscle mass, seizures, dysphagia, chronic constipation, among others. Implying a challenging management due to the complexity of the symptoms. A heterozygous pathogenic variant in the SLC16A2 gene, clinically unaffected, was identified in the mother.