DrGhaniya
DrSheela Nampoothiri (PaedGenetics)
Dec Jayakumar
AIMS KOCHI
Fifteen year old male, genetically proven Morquio syndrome (MPS-IV) diagnosed at 1 years 5 months presented with complaints of urethral pain
He is on
KSP
intermittent self catheterisation and fever since one day.No h/o cough/vomiting/ abdominal pain/ loose stools,sick contact
H/o TB contact + ( Mother – lymph node TB -2017 treated with ATT x 1 Year)
Antenatal – 2nd child of NCM
Antenatal – uneventful
Natal – Term / normal / BW – 2.7 Kg/ CIABPost Natal treated with phototherapy for three days
At one year of age , evaluation of the child for recurrent chest infections revealed chest deformity and referred to AIMS for genetic workup.
Genetic test – showed Moquio syndrome (MPS-IV A)
At three years of age – diagnosed to have cranio-vertebral abnormality, was planned for surgery but could not be done due to impaired chest expansion
At eleven years – he survived Covid 19
Family History – Mother – H/o TB lymph node
Developmental History – Goes to school.In 9th grade. wheel chair bounds since 9th std.
IQ – 100
Not able to sit since March 2024
Even at school, attends classes lying in bed
Started physiotherapy last month , stopped dur to increased pain.
Vision – Corneal clouding +
Hearing – Left side hearing loss + ( not evaluated)
O/E : Bed Bound
Neck extended
Back arched
Deep respirations
Vitals : Temp :102 F , PR : 98/min , RR – 28/min , SpO2 : 94% on Room air BP: 100/70 mmHg
No pallor, icterus, cyanois, clubbing,lymphadenopathy
Weight – 23 Kg
Height – 91 cm
Head to Foot Examination:
Short neck and trunk
Corneal clouding
Pectus Carinatum
Severe Kyphoscholiosis
Hyperextensible wrists
Genu Valgum
SMR – Grade 4
CNS – Generalized Hypotonia
Power – <3/5
Reflexes – Brisk
Sensory – Normal sensation to touch/pain/temperature
Cranial nerve 8 : some hearing loss on left side
Rest of the cranial nerves – normal
RS : equal air entry vesicular breathing
CVS : S1,S2 +
P/A : soft, non-tender, Bowel sounds +
Mucopolysaccharidosis IV (MPS-IV): Also known as Morquio syndrome, a lysosomal storage disorder affecting keratan sulfate degradation.
Subtypes:
• MPS-IVA: Caused a deficiency of N-acetylgalactosamine-6-sulfatase (encoded the GALNS gene on chromosome 16q24.3).
• MPS-IVB: Caused a deficiency of β-galactosidase (encoded the GLB1 gene on chromosome 3p21.33).
• β-Galactosidase Functions:
• Catalyzes GM1 ganglioside degradation.
• Involved in keratan sulfate endohydrolysis.
• Most pathogenic variants of GLB1 lead to generalized gangliosidosis (a neurodegenerative disorder).
• Common Variant:W273L pathogenic variant of GLB1 often causes Morquio B disease (either homozygous or compound heterozygous)
Key Characteristics of Morquio Syndrome:
• Short-trunk dwarfism.
• Fine corneal deposits.
• Skeletal dysplasia distinct from other mucopolysaccharidoses.
• Intelligence is usually preserved.
Severity:
• MPS-IVA: More severe, with an adult height of <125 cm.
• MPS-IVB: Milder, with an adult height of >150 cm.
• Both subtypes show variability in expression.
Early Symptoms:
• Genu valgum (knock knees).
• Kyphosis.
• Short trunk and neck.
• Growth retardation.
• Waddling gait and frequent falls.
• Extraskeletal Manifestations:
• Mild corneal clouding.
• Small teeth with thin enamel.
• Frequent caries.
• Possible hepatomegaly and cardiac valve lesions.
• Cervical Spine Instability:
• Regular presence of instability of the odontoid process and ligamentous laxity.
• Can lead to atlantoaxial instability and life-threatening dislocation.
Early surgical intervention (posterior spinal fusion) can be lifesaving, ideally before the onset of cervical myelopathy.