Spotlight on Syndromes: An SLPs Perspective on Menkes Syndrome

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November is Menkes Awareness month, so today Olga Z. Porterfield will be contributing a post on the Menkes Syndrome.

Menkes Syndrome (MNK), also known as Menkes disease, copper transport disease, steely hair disease, kinky hair disease, or Menkes kinky hair syndrome, is a disorder originally described by John Hans Menkes (1928–2008), which affects copper levels in the body, leading to copper deficiency. It is an x-linked recessive disorder, and is therefore considerably more common in males with females requiring two defective alleles to develop the disease. It is caused by a defective gene named ATP7A gene that regulates the metabolism of copper in the body.

Physical Characteristics and Developmental Abnormalities:

MNK is characterized by growth failure, and deterioration of the nervous system. Children with MNK have strikingly peculiar hair, which is kinky, colorless or steel-colored, and easily broken. Onset of MNK typically begins during infancy. Signs and symptoms of this disorder include failure to thrive, subnormal body temperature, weak muscle tone (hypotonia), sagging facial features, seizures, mental retardation, blue sclera and developmental delay. There can be extensive neurodegeneration in the gray matter of the brain. Arteries in the brain can also be twisted with frayed and split inner walls. This can lead to rupture or blockage of the arteries. Weakened bones (osteoporosis) may result in fractures. Affected infants may be born prematurely, but appear healthy at birth and develop normally for 6 to 8 weeks. Then there will be severe developmental delay and a loss of early developmental skills. The symptoms begin to appear which is largely the result of abnormal intestinal copper absorption with secondary deficiency in copper-dependent mitochondrial enzymes. In rare cases, symptoms begin later in childhood and are less severe.

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Statistics:

Incidence is reported to be 1/300,000 in Europe and 1/360,000 in Japan. In Australia, the birth incidence is reported to be much higher (1/50,000-100,000), which may be due to a founder effect ( the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population). MNK is an X-linked disease primarily affecting males while females are usually unaffected carriers.

Differential Diagnosis

MNK may mimic non-accidental trauma (NAT) with retinal hemorrhage and bilateral subdural hematomas. Hence, it is important to rule out NAT, especially when other intracranial signs of MNK aren’t seen.  Some MNK mutations such as “leaky splice site” mutations of the APTP7A do contribute to production of protein needed for copper transport, however, it is typically not enough. There’s also a condition called the Occipital Horn Syndrome (sometimes called X-linked cutis laxa or Ehlers-Danlos type 9) which is a mild form of Menkes syndrome that begins in early to middle childhood. It is characterized by calcium deposits in a bone at the base of the skull (occipital bone), coarse hair, and loose skin and joints. Marfan syndrome, cutis laxa, mitochondrial disorders, osteogenesis imperfecta and child abuse, may also need to be ruled out when making a differential diagnosis.

Behavior: 

Children with MNK are described as “irritable babies”. In my experience with only one “Menkes” student, whom I have been following for 2 years, he is very social, generally in a great mood, has a wide grin, eager to interact with anyone.

Cognition:

Children with MNK present with severe global developmental delays

Speech and Language Issues  

There is no information in sources due to the rare incidence and low life expectancy. My student has been on G-tube feeding, NPO since infancy. Attempts to introduce AAC have met with minimal success despite his communicative intent, due to cognitive and motor limitations. He is able to shift eye gaze to “eye point” to a preferred item given a choice of two. This response is not always reliable. He seems to have one volitional hand motion: extension of the right pointer finger. Initially, our team had high hopes to use this for communication. Unfortunately, this has also proven unreliable. The student is able to vocalize in a cooing manner on occasion, largely dependent on his respiratory status and position in space. Sitting in his highly adapted travel stroller allows for maximum respiratory comfort and vocalization, as well as ability for limited arms movements. Student is able to press a single switch or a Speech Generating Device with physical support at the elbow.  

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Current Interventions

Treatment with daily copper injections for the first 3 years of life may improve the outcome in Menkes disease if it begins within days after birth and if the child’s body has some ability to process copper.  Other treatment is symptomatic and supportive. In a recent  study researchers at the National Institute of Child Health and Human Development (NICHD) tested a treatment to add a normal copy of ATP7A to mice with a malfunctioning copy of the gene. Their results suggest that one day it might be possible to provide patients with a functioning ATP7A gene.

Treatment focuses on kidney-related symptoms (student requires catheterization several times a day, G-tube care, respiratory monitoring and treatment as needed. In addition, occasional joint problems (elbow dislocations) due to hypotonia, may occur. A recent respiratory crisis was due to a diaphragmatic hernia, which required surgical correction. Medical management requires collaboration between many professionals: nephrologist, pulmonologist, cardiologist, medical geneticist, gastro-enterologist, urologist, surgeon, nurses, pediatrician, to name a few. Educational team should include special education, PT, OT, speech therapy, social work.

Conclusion

The prognosis for babies with MNK is poor as most children die within the first decade of life. While medical sources report a life expectancy of less than 3 years, my one student is now almost 4 years old. Although this condition is considered lethal, quality of life for the child and the family can be enhanced through supportive intervention.

References:

olga - vegas - faceOlga  Z. Porterfield, M.S., CCC-SLP is a speech-language pathologist with over 30 years of professional experience in pediatric services. She has received her B.S. from Moscow State Pedagogical Institute, Moscow, Russia, in 1977. She immigrated to the US in 1979 and received her M.S. in Communication Disorders from Boston University in 1982. She has worked as an SLP in the states of MA. IL and NY. Presently works in CloverPatch preschool in Glenville, NY.

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