Johanson-Blizzard Syndrome Affects Both Boys and Girls
Yes, Johanson-Blizzard syndrome (JBS) affects both boys and girls as it is an autosomal recessive genetic disorder. 1, 2, 3
Genetic Basis and Inheritance Pattern
- JBS is caused by mutations in the ubiquitin protein ligase E3 component n-recognin 1 (UBR1) gene 1, 2
- The syndrome follows an autosomal recessive inheritance pattern, meaning both males and females can be affected equally when they inherit two mutated copies of the UBR1 gene (one from each parent) 3
- Various types of mutations in the UBR1 gene have been documented in affected individuals, including frameshift mutations, compound heterozygous variants, and homozygous mutations 2, 4, 5
Evidence from Case Reports
- Multiple case reports document JBS in both sexes:
- A 12-year-old girl with JBS born to consanguineous parents, diagnosed with a novel frameshift mutation in the UBR1 gene 1
- A 3-year-old boy with severe growth retardation and pancreatic insufficiency, diagnosed with two compound heterozygous variants in the UBR1 gene 2
- A 2-month-old female infant with oily diarrhea, facial dysmorphia, and other characteristic features of JBS 4
- A male infant with typical JBS symptoms plus anemia requiring frequent blood transfusions 3
- A 3-year-old mentally normal girl with JBS carrying two novel UBR1 mutations 5
Clinical Manifestations in Both Sexes
Both boys and girls with JBS present with similar core clinical features:
- Exocrine pancreatic insufficiency 1, 2, 3
- Distinctive facial features, particularly hypoplasia or aplasia of the alae nasi (underdeveloped nasal wings) 1, 2
- Congenital scalp defects (cutis aplasia) 1, 4
- Growth retardation and failure to thrive 1, 3
- Sensorineural hearing loss 1, 4
- Developmental delays of varying severity 1, 3
Some sex-specific manifestations may occur:
- Boys may present with genitourinary anomalies such as maldescent of testicles 2
Important Clinical Considerations
- Early diagnosis is crucial for both male and female patients to initiate appropriate management 1
- Multidisciplinary care is essential for all affected individuals, regardless of sex 1
- Treatment focuses on managing pancreatic insufficiency with enzyme replacement therapy and addressing other organ system involvement 1, 2
- Genetic counseling should be offered to families with affected children, as parents are typically carriers of the mutation 1, 2
Diagnostic Approach
- Clinical diagnosis is based on characteristic features, particularly the distinctive facial appearance and pancreatic insufficiency 1, 2
- Imaging studies (ultrasound, CT) may reveal complete fatty replacement of the pancreas 2
- Molecular genetic testing to identify mutations in the UBR1 gene confirms the diagnosis 1, 2, 4
- Prenatal diagnosis is possible for future pregnancies when the causative mutations have been identified in a family 2