Poretti-Boltshauser Syndrome: A Report of Two Cases From Bahrain With a Novel Mutation and Literature Review

Poretti-Boltshauser syndrome (PTBHS) is a neuro-ophthalmological rare genetic disease that has an autosomal recessive inheritance that occurs as a consequence of a mutation in the LAMA1 gene. This gene is important in the development of blood vessels and certain organs, including the cerebellum and the retina. PTBHS is characterized by specific cerebellar abnormalities that manifest in the development of certain clinical features, including cerebellar ataxia, intellectual disability, and delayed language and motor development. In addition to the cerebellar manifestations, retinal abnormalities were noted in patients with PTBHS, such as ocular motor apraxia, severe myopia, strabismus, and retinal dystrophy. In this report, we describe a three-year-old female child diagnosed with PTBHS after assessing and reviewing her clinical presentation and work-up results at Salmaniya Medical Hospital. She presented with nystagmus, poor eye fixation, and delayed gross motor development. The MRI findings were almost subtle, and the diagnosis was confirmed mainly based on the genetic results. <i>LAMA1</i>: c.1243del chr18-7042162TG>T (GRCh37 format) or p.His415Ilefs*78 with transcript ID as NM_005559.4 homozygous mutation was found by whole exome sequencing. Her older sister was also diagnosed with the same disease afterwards by target mutation. Most genetic diseases are difficult to cure, and the management relies mainly on supportive treatment. For that, doctors should pay close attention to the small details in the clinical presentation and investigation findings and always involve a specialized doctor in case any small concern is raised.